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0efdf0fe 1.. _bgp:
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2
3***
4BGP
5***
6
8fcedbd2 7:abbr:`BGP` stands for Border Gateway Protocol. The latest BGP version is 4.
d1e7591e 8BGP-4 is one of the Exterior Gateway Protocols and the de facto standard
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9interdomain routing protocol. BGP-4 is described in :rfc:`1771` and updated by
10:rfc:`4271`. :rfc:`2858` adds multiprotocol support to BGP-4.
42fc5d26 11
0efdf0fe 12.. _starting-bgp:
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13
14Starting BGP
15============
16
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17The default configuration file of *bgpd* is :file:`bgpd.conf`. *bgpd* searches
18the current directory first, followed by |INSTALL_PREFIX_ETC|/bgpd.conf. All of
19*bgpd*'s commands must be configured in :file:`bgpd.conf` when the integrated
20config is not being used.
42fc5d26 21
c1a54c05 22*bgpd* specific invocation options are described below. Common options may also
0efdf0fe 23be specified (:ref:`common-invocation-options`).
42fc5d26 24
c1a54c05 25.. program:: bgpd
42fc5d26 26
c9365894 27.. option:: -p, --bgp_port <port>
42fc5d26 28
db759bb0 29 Set the bgp protocol's port number. When port number is 0, that means do not
30 listen bgp port.
42fc5d26 31
c9365894 32.. option:: -l, --listenon
42fc5d26 33
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34 Specify a specific IP address for bgpd to listen on, rather than its default
35 of ``0.0.0.0`` / ``::``. This can be useful to constrain bgpd to an internal
36 address, or to run multiple bgpd processes on one host.
42fc5d26 37
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38.. option:: -n, --no_kernel
39
40 Do not install learned routes into the linux kernel. This option is useful
41 for a route-reflector environment or if you are running multiple bgp
42 processes in the same namespace. This option is different than the --no_zebra
43 option in that a ZAPI connection is made.
44
45.. option:: -S, --skip_runas
46
47 Skip the normal process of checking capabilities and changing user and group
48 information.
49
50.. option:: -e, --ecmp
51
52 Run BGP with a limited ecmp capability, that is different than what BGP
53 was compiled with. The value specified must be greater than 0 and less
54 than or equal to the MULTIPATH_NUM specified on compilation.
55
56.. option:: -Z, --no_zebra
57
58 Do not communicate with zebra at all. This is different than the --no_kernel
59 option in that we do not even open a ZAPI connection to the zebra process.
60
61.. option:: -s, --socket_size
62
63 When opening tcp connections to our peers, set the socket send buffer
64 size that the kernel will use for the peers socket. This option
65 is only really useful at a very large scale. Experimentation should
66 be done to see if this is helping or not at the scale you are running
67 at.
68
69LABEL MANAGER
70-------------
71
72.. option:: -I, --int_num
73
74 Set zclient id. This is required when using Zebra label manager in proxy mode.
75
8fcedbd2 76.. _bgp-basic-concepts:
42fc5d26 77
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78Basic Concepts
79==============
42fc5d26 80
8fcedbd2 81.. _bgp-autonomous-systems:
c3c5a71f 82
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83Autonomous Systems
84------------------
42fc5d26 85
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86From :rfc:`1930`:
87
88 An AS is a connected group of one or more IP prefixes run by one or more
89 network operators which has a SINGLE and CLEARLY DEFINED routing policy.
90
91Each AS has an identifying number associated with it called an :abbr:`ASN
92(Autonomous System Number)`. This is a two octet value ranging in value from 1
93to 65535. The AS numbers 64512 through 65535 are defined as private AS numbers.
94Private AS numbers must not be advertised on the global Internet.
95
96The :abbr:`ASN (Autonomous System Number)` is one of the essential elements of
8fcedbd2 97BGP. BGP is a distance vector routing protocol, and the AS-Path framework
c0868e8b 98provides distance vector metric and loop detection to BGP.
42fc5d26 99
c0868e8b 100.. seealso:: :rfc:`1930`
42fc5d26 101
8fcedbd2 102.. _bgp-address-families:
42fc5d26 103
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104Address Families
105----------------
42fc5d26 106
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107Multiprotocol extensions enable BGP to carry routing information for multiple
108network layer protocols. BGP supports an Address Family Identifier (AFI) for
109IPv4 and IPv6. Support is also provided for multiple sets of per-AFI
110information via the BGP Subsequent Address Family Identifier (SAFI). FRR
111supports SAFIs for unicast information, labeled information (:rfc:`3107` and
112:rfc:`8277`), and Layer 3 VPN information (:rfc:`4364` and :rfc:`4659`).
c3c5a71f 113
8fcedbd2 114.. _bgp-route-selection:
42fc5d26 115
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116Route Selection
117---------------
42fc5d26 118
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119The route selection process used by FRR's BGP implementation uses the following
120decision criterion, starting at the top of the list and going towards the
121bottom until one of the factors can be used.
42fc5d26 122
8fcedbd2 1231. **Weight check**
42fc5d26 124
c1a54c05 125 Prefer higher local weight routes to lower routes.
42fc5d26 126
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1272. **Local preference check**
128
c1a54c05 129 Prefer higher local preference routes to lower.
42fc5d26 130
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1313. **Local route check**
132
c1a54c05 133 Prefer local routes (statics, aggregates, redistributed) to received routes.
42fc5d26 134
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1354. **AS path length check**
136
c1a54c05 137 Prefer shortest hop-count AS_PATHs.
42fc5d26 138
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1395. **Origin check**
140
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141 Prefer the lowest origin type route. That is, prefer IGP origin routes to
142 EGP, to Incomplete routes.
42fc5d26 143
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1446. **MED check**
145
c1a54c05 146 Where routes with a MED were received from the same AS, prefer the route
0efdf0fe 147 with the lowest MED. :ref:`bgp-med`.
42fc5d26 148
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1497. **External check**
150
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151 Prefer the route received from an external, eBGP peer over routes received
152 from other types of peers.
42fc5d26 153
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1548. **IGP cost check**
155
c1a54c05 156 Prefer the route with the lower IGP cost.
42fc5d26 157
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1589. **Multi-path check**
159
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160 If multi-pathing is enabled, then check whether the routes not yet
161 distinguished in preference may be considered equal. If
9e146a81 162 :clicmd:`bgp bestpath as-path multipath-relax` is set, all such routes are
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163 considered equal, otherwise routes received via iBGP with identical AS_PATHs
164 or routes received from eBGP neighbours in the same AS are considered equal.
42fc5d26 165
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16610. **Already-selected external check**
167
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168 Where both routes were received from eBGP peers, then prefer the route
169 which is already selected. Note that this check is not applied if
170 :clicmd:`bgp bestpath compare-routerid` is configured. This check can
171 prevent some cases of oscillation.
172
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17311. **Router-ID check**
174
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175 Prefer the route with the lowest `router-ID`. If the route has an
176 `ORIGINATOR_ID` attribute, through iBGP reflection, then that router ID is
177 used, otherwise the `router-ID` of the peer the route was received from is
178 used.
179
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18012. **Cluster-List length check**
181
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182 The route with the shortest cluster-list length is used. The cluster-list
183 reflects the iBGP reflection path the route has taken.
184
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18513. **Peer address**
186
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187 Prefer the route received from the peer with the higher transport layer
188 address, as a last-resort tie-breaker.
42fc5d26 189
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190.. _bgp-capability-negotiation:
191
192Capability Negotiation
193----------------------
194
195When adding IPv6 routing information exchange feature to BGP. There were some
196proposals. :abbr:`IETF (Internet Engineering Task Force)`
197:abbr:`IDR (Inter Domain Routing)` adopted a proposal called Multiprotocol
198Extension for BGP. The specification is described in :rfc:`2283`. The protocol
199does not define new protocols. It defines new attributes to existing BGP. When
200it is used exchanging IPv6 routing information it is called BGP-4+. When it is
201used for exchanging multicast routing information it is called MBGP.
202
203*bgpd* supports Multiprotocol Extension for BGP. So if a remote peer supports
204the protocol, *bgpd* can exchange IPv6 and/or multicast routing information.
205
206Traditional BGP did not have the feature to detect a remote peer's
207capabilities, e.g. whether it can handle prefix types other than IPv4 unicast
208routes. This was a big problem using Multiprotocol Extension for BGP in an
209operational network. :rfc:`2842` adopted a feature called Capability
210Negotiation. *bgpd* use this Capability Negotiation to detect the remote peer's
211capabilities. If a peer is only configured as an IPv4 unicast neighbor, *bgpd*
212does not send these Capability Negotiation packets (at least not unless other
213optional BGP features require capability negotiation).
214
215By default, FRR will bring up peering with minimal common capability for the
216both sides. For example, if the local router has unicast and multicast
217capabilities and the remote router only has unicast capability the local router
218will establish the connection with unicast only capability. When there are no
219common capabilities, FRR sends Unsupported Capability error and then resets the
220connection.
221
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222.. _bgp-router-configuration:
223
224BGP Router Configuration
225========================
226
227ASN and Router ID
228-----------------
229
230First of all you must configure BGP router with the :clicmd:`router bgp ASN`
231command. The AS number is an identifier for the autonomous system. The BGP
232protocol uses the AS number for detecting whether the BGP connection is
233internal or external.
234
235.. index:: router bgp ASN
236.. clicmd:: router bgp ASN
237
238 Enable a BGP protocol process with the specified ASN. After
239 this statement you can input any `BGP Commands`.
240
241.. index:: no router bgp ASN
242.. clicmd:: no router bgp ASN
243
244 Destroy a BGP protocol process with the specified ASN.
245
246.. index:: bgp router-id A.B.C.D
247.. clicmd:: bgp router-id A.B.C.D
248
249 This command specifies the router-ID. If *bgpd* connects to *zebra* it gets
250 interface and address information. In that case default router ID value is
251 selected as the largest IP Address of the interfaces. When `router zebra` is
252 not enabled *bgpd* can't get interface information so `router-id` is set to
253 0.0.0.0. So please set router-id by hand.
254
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255
256.. _bgp-multiple-autonomous-systems:
257
258Multiple Autonomous Systems
259---------------------------
260
261FRR's BGP implementation is capable of running multiple autonomous systems at
262once. Each configured AS corresponds to a :ref:`zebra-vrf`. In the past, to get
263the same functionality the network administrator had to run a new *bgpd*
264process; using VRFs allows multiple autonomous systems to be handled in a
265single process.
266
267When using multiple autonomous systems, all router config blocks after the
268first one must specify a VRF to be the target of BGP's route selection. This
269VRF must be unique within respect to all other VRFs being used for the same
270purpose, i.e. two different autonomous systems cannot use the same VRF.
271However, the same AS can be used with different VRFs.
272
273.. note::
274
275 The separated nature of VRFs makes it possible to peer a single *bgpd*
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276 process to itself, on one machine. Note that this can be done fully within
277 BGP without a corresponding VRF in the kernel or Zebra, which enables some
278 practical use cases such as :ref:`route reflectors <bgp-route-reflector>`
279 and route servers.
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280
281Configuration of additional autonomous systems, or of a router that targets a
282specific VRF, is accomplished with the following command:
283
284.. index:: router bgp ASN vrf VRFNAME
285.. clicmd:: router bgp ASN vrf VRFNAME
286
287 ``VRFNAME`` is matched against VRFs configured in the kernel. When ``vrf
288 VRFNAME`` is not specified, the BGP protocol process belongs to the default
289 VRF.
290
291An example configuration with multiple autonomous systems might look like this:
292
293.. code-block:: frr
294
295 router bgp 1
296 neighbor 10.0.0.1 remote-as 20
297 neighbor 10.0.0.2 remote-as 30
298 !
299 router bgp 2 vrf blue
300 neighbor 10.0.0.3 remote-as 40
301 neighbor 10.0.0.4 remote-as 50
302 !
303 router bgp 3 vrf red
304 neighbor 10.0.0.5 remote-as 60
305 neighbor 10.0.0.6 remote-as 70
306 ...
307
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308.. seealso:: :ref:`bgp-vrf-route-leaking`
309.. seealso:: :ref:`zebra-vrf`
310
311
312.. _bgp-views:
313
314Views
315-----
316
317In addition to supporting multiple autonomous systems, FRR's BGP implementation
318also supports *views*.
319
320BGP views are almost the same as normal BGP processes, except that routes
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321selected by BGP are not installed into the kernel routing table. Each BGP view
322provides an independent set of routing information which is only distributed
323via BGP. Multiple views can be supported, and BGP view information is always
324independent from other routing protocols and Zebra/kernel routes. BGP views use
325the core instance (i.e., default VRF) for communication with peers.
edde3ce9 326
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327.. index:: router bgp AS-NUMBER view NAME
328.. clicmd:: router bgp AS-NUMBER view NAME
329
330 Make a new BGP view. You can use an arbitrary word for the ``NAME``. Routes
331 selected by the view are not installed into the kernel routing table.
332
333 With this command, you can setup Route Server like below.
334
335 .. code-block:: frr
336
337 !
338 router bgp 1 view 1
339 neighbor 10.0.0.1 remote-as 2
340 neighbor 10.0.0.2 remote-as 3
341 !
342 router bgp 2 view 2
343 neighbor 10.0.0.3 remote-as 4
344 neighbor 10.0.0.4 remote-as 5
345
346.. index:: show [ip] bgp view NAME
347.. clicmd:: show [ip] bgp view NAME
348
349 Display the routing table of BGP view ``NAME``.
350
351
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352Route Selection
353---------------
c3c5a71f 354
c1a54c05 355.. index:: bgp bestpath as-path confed
29adcd50 356.. clicmd:: bgp bestpath as-path confed
42fc5d26 357
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358 This command specifies that the length of confederation path sets and
359 sequences should should be taken into account during the BGP best path
360 decision process.
42fc5d26 361
c3c5a71f 362.. index:: bgp bestpath as-path multipath-relax
29adcd50 363.. clicmd:: bgp bestpath as-path multipath-relax
42fc5d26 364
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365 This command specifies that BGP decision process should consider paths
366 of equal AS_PATH length candidates for multipath computation. Without
367 the knob, the entire AS_PATH must match for multipath computation.
c3c5a71f 368
29adcd50 369.. clicmd:: bgp bestpath compare-routerid
42fc5d26 370
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371 Ensure that when comparing routes where both are equal on most metrics,
372 including local-pref, AS_PATH length, IGP cost, MED, that the tie is broken
373 based on router-ID.
42fc5d26 374
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375 If this option is enabled, then the already-selected check, where
376 already selected eBGP routes are preferred, is skipped.
42fc5d26 377
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378 If a route has an `ORIGINATOR_ID` attribute because it has been reflected,
379 that `ORIGINATOR_ID` will be used. Otherwise, the router-ID of the peer the
380 route was received from will be used.
42fc5d26 381
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382 The advantage of this is that the route-selection (at this point) will be
383 more deterministic. The disadvantage is that a few or even one lowest-ID
d1e7591e 384 router may attract all traffic to otherwise-equal paths because of this
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385 check. It may increase the possibility of MED or IGP oscillation, unless
386 other measures were taken to avoid these. The exact behaviour will be
387 sensitive to the iBGP and reflection topology.
42fc5d26 388
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389.. _bgp-distance:
390
391Administrative Distance Metrics
392-------------------------------
393
394.. index:: distance bgp (1-255) (1-255) (1-255)
395.. clicmd:: distance bgp (1-255) (1-255) (1-255)
396
397 This command change distance value of BGP. The arguments are the distance
398 values for for external routes, internal routes and local routes
399 respectively.
400
401.. index:: distance (1-255) A.B.C.D/M
402.. clicmd:: distance (1-255) A.B.C.D/M
403
404.. index:: distance (1-255) A.B.C.D/M WORD
405.. clicmd:: distance (1-255) A.B.C.D/M WORD
406
407 Sets the administrative distance for a particular route.
42fc5d26 408
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409.. _bgp-requires-policy:
410
411Require policy on EBGP
412-------------------------------
413
414.. index:: [no] bgp ebgp-requires-policy
415.. clicmd:: [no] bgp ebgp-requires-policy
416
417 This command requires incoming and outgoing filters to be applied for eBGP sessions. Without the incoming filter, no routes will be accepted. Without the outgoing filter, no routes will be announced.
418
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419Reject routes with AS_SET or AS_CONFED_SET types
420-------------------------------
421
422.. index:: [no] bgp reject-as-sets
423.. clicmd:: [no] bgp reject-as-sets
424
425 This command enables rejection of incoming and outgoing routes having AS_SET or AS_CONFED_SET type.
426
0efdf0fe 427.. _bgp-route-flap-dampening:
42fc5d26 428
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429Route Flap Dampening
430--------------------
42fc5d26 431
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432.. clicmd:: bgp dampening (1-45) (1-20000) (1-20000) (1-255)
433
c1a54c05 434 This command enables BGP route-flap dampening and specifies dampening parameters.
42fc5d26 435
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436 half-life
437 Half-life time for the penalty
42fc5d26 438
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439 reuse-threshold
440 Value to start reusing a route
42fc5d26 441
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442 suppress-threshold
443 Value to start suppressing a route
42fc5d26 444
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445 max-suppress
446 Maximum duration to suppress a stable route
42fc5d26 447
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448 The route-flap damping algorithm is compatible with :rfc:`2439`. The use of
449 this command is not recommended nowadays.
42fc5d26 450
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451 At the moment, route-flap dampening is not working per VRF and is working only
452 for IPv4 unicast and multicast.
453
c1a54c05 454.. seealso::
8fcedbd2 455 https://www.ripe.net/publications/docs/ripe-378
42fc5d26 456
0efdf0fe 457.. _bgp-med:
42fc5d26 458
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459Multi-Exit Discriminator
460------------------------
42fc5d26 461
8fcedbd2 462The BGP :abbr:`MED (Multi-Exit Discriminator)` attribute has properties which
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463can cause subtle convergence problems in BGP. These properties and problems
464have proven to be hard to understand, at least historically, and may still not
465be widely understood. The following attempts to collect together and present
466what is known about MED, to help operators and FRR users in designing and
467configuring their networks.
42fc5d26 468
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469The BGP :abbr:`MED` attribute is intended to allow one AS to indicate its
470preferences for its ingress points to another AS. The MED attribute will not be
471propagated on to another AS by the receiving AS - it is 'non-transitive' in the
472BGP sense.
42fc5d26 473
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474E.g., if AS X and AS Y have 2 different BGP peering points, then AS X might set
475a MED of 100 on routes advertised at one and a MED of 200 at the other. When AS
476Y selects between otherwise equal routes to or via AS X, AS Y should prefer to
477take the path via the lower MED peering of 100 with AS X. Setting the MED
478allows an AS to influence the routing taken to it within another, neighbouring
479AS.
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480
481In this use of MED it is not really meaningful to compare the MED value on
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482routes where the next AS on the paths differs. E.g., if AS Y also had a route
483for some destination via AS Z in addition to the routes from AS X, and AS Z had
484also set a MED, it wouldn't make sense for AS Y to compare AS Z's MED values to
485those of AS X. The MED values have been set by different administrators, with
486different frames of reference.
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487
488The default behaviour of BGP therefore is to not compare MED values across
dc1046f7 489routes received from different neighbouring ASes. In FRR this is done by
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490comparing the neighbouring, left-most AS in the received AS_PATHs of the routes
491and only comparing MED if those are the same.
492
493Unfortunately, this behaviour of MED, of sometimes being compared across routes
494and sometimes not, depending on the properties of those other routes, means MED
495can cause the order of preference over all the routes to be undefined. That is,
496given routes A, B, and C, if A is preferred to B, and B is preferred to C, then
497a well-defined order should mean the preference is transitive (in the sense of
013f9762 498orders [#med-transitivity-rant]_) and that A would be preferred to C.
42fc5d26 499
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500However, when MED is involved this need not be the case. With MED it is
501possible that C is actually preferred over A. So A is preferred to B, B is
502preferred to C, but C is preferred to A. This can be true even where BGP
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503defines a deterministic 'most preferred' route out of the full set of A,B,C.
504With MED, for any given set of routes there may be a deterministically
505preferred route, but there need not be any way to arrange them into any order
506of preference. With unmodified MED, the order of preference of routes literally
507becomes undefined.
42fc5d26 508
c3c5a71f 509That MED can induce non-transitive preferences over routes can cause issues.
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510Firstly, it may be perceived to cause routing table churn locally at speakers;
511secondly, and more seriously, it may cause routing instability in iBGP
512topologies, where sets of speakers continually oscillate between different
513paths.
42fc5d26 514
c3c5a71f 515The first issue arises from how speakers often implement routing decisions.
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516Though BGP defines a selection process that will deterministically select the
517same route as best at any given speaker, even with MED, that process requires
518evaluating all routes together. For performance and ease of implementation
519reasons, many implementations evaluate route preferences in a pair-wise fashion
520instead. Given there is no well-defined order when MED is involved, the best
521route that will be chosen becomes subject to implementation details, such as
522the order the routes are stored in. That may be (locally) non-deterministic,
523e.g.: it may be the order the routes were received in.
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524
525This indeterminism may be considered undesirable, though it need not cause
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526problems. It may mean additional routing churn is perceived, as sometimes more
527updates may be produced than at other times in reaction to some event .
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528
529This first issue can be fixed with a more deterministic route selection that
c3c5a71f 530ensures routes are ordered by the neighbouring AS during selection.
9e146a81 531:clicmd:`bgp deterministic-med`. This may reduce the number of updates as routes
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532are received, and may in some cases reduce routing churn. Though, it could
533equally deterministically produce the largest possible set of updates in
534response to the most common sequence of received updates.
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535
536A deterministic order of evaluation tends to imply an additional overhead of
c3c5a71f 537sorting over any set of n routes to a destination. The implementation of
dc1046f7 538deterministic MED in FRR scales significantly worse than most sorting
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539algorithms at present, with the number of paths to a given destination. That
540number is often low enough to not cause any issues, but where there are many
541paths, the deterministic comparison may quickly become increasingly expensive
542in terms of CPU.
543
544Deterministic local evaluation can *not* fix the second, more major, issue of
545MED however. Which is that the non-transitive preference of routes MED can
546cause may lead to routing instability or oscillation across multiple speakers
547in iBGP topologies. This can occur with full-mesh iBGP, but is particularly
548problematic in non-full-mesh iBGP topologies that further reduce the routing
549information known to each speaker. This has primarily been documented with iBGP
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550:ref:`route-reflection <bgp-route-reflector>` topologies. However, any
551route-hiding technologies potentially could also exacerbate oscillation with MED.
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552
553This second issue occurs where speakers each have only a subset of routes, and
554there are cycles in the preferences between different combinations of routes -
555as the undefined order of preference of MED allows - and the routes are
556distributed in a way that causes the BGP speakers to 'chase' those cycles. This
557can occur even if all speakers use a deterministic order of evaluation in route
558selection.
559
560E.g., speaker 4 in AS A might receive a route from speaker 2 in AS X, and from
561speaker 3 in AS Y; while speaker 5 in AS A might receive that route from
562speaker 1 in AS Y. AS Y might set a MED of 200 at speaker 1, and 100 at speaker
5633. I.e, using ASN:ID:MED to label the speakers:
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564
565::
566
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567 .
568 /---------------\\
42fc5d26 569 X:2------|--A:4-------A:5--|-Y:1:200
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570 Y:3:100--|-/ |
571 \\---------------/
c3c5a71f 572
42fc5d26 573
42fc5d26 574
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575Assuming all other metrics are equal (AS_PATH, ORIGIN, 0 IGP costs), then based
576on the RFC4271 decision process speaker 4 will choose X:2 over Y:3:100, based
577on the lower ID of 2. Speaker 4 advertises X:2 to speaker 5. Speaker 5 will
578continue to prefer Y:1:200 based on the ID, and advertise this to speaker 4.
579Speaker 4 will now have the full set of routes, and the Y:1:200 it receives
580from 5 will beat X:2, but when speaker 4 compares Y:1:200 to Y:3:100 the MED
581check now becomes active as the ASes match, and now Y:3:100 is preferred.
582Speaker 4 therefore now advertises Y:3:100 to 5, which will also agrees that
583Y:3:100 is preferred to Y:1:200, and so withdraws the latter route from 4.
584Speaker 4 now has only X:2 and Y:3:100, and X:2 beats Y:3:100, and so speaker 4
585implicitly updates its route to speaker 5 to X:2. Speaker 5 sees that Y:1:200
586beats X:2 based on the ID, and advertises Y:1:200 to speaker 4, and the cycle
587continues.
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588
589The root cause is the lack of a clear order of preference caused by how MED
590sometimes is and sometimes is not compared, leading to this cycle in the
591preferences between the routes:
592
593::
594
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595 .
596 /---> X:2 ---beats---> Y:3:100 --\\
597 | |
598 | |
599 \\---beats--- Y:1:200 <---beats---/
c3c5a71f 600
42fc5d26 601
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602
603This particular type of oscillation in full-mesh iBGP topologies can be
604avoided by speakers preferring already selected, external routes rather than
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605choosing to update to new a route based on a post-MED metric (e.g. router-ID),
606at the cost of a non-deterministic selection process. FRR implements this, as
607do many other implementations, so long as it is not overridden by setting
9e146a81 608:clicmd:`bgp bestpath compare-routerid`, and see also
8fcedbd2 609:ref:`bgp-route-selection`.
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610
611However, more complex and insidious cycles of oscillation are possible with
c3c5a71f 612iBGP route-reflection, which are not so easily avoided. These have been
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613documented in various places. See, e.g.:
614
615- [bgp-route-osci-cond]_
616- [stable-flexible-ibgp]_
617- [ibgp-correctness]_
618
619for concrete examples and further references.
620
621There is as of this writing *no* known way to use MED for its original purpose;
622*and* reduce routing information in iBGP topologies; *and* be sure to avoid the
623instability problems of MED due the non-transitive routing preferences it can
624induce; in general on arbitrary networks.
625
626There may be iBGP topology specific ways to reduce the instability risks, even
627while using MED, e.g.: by constraining the reflection topology and by tuning
013f9762 628IGP costs between route-reflector clusters, see :rfc:`3345` for details. In the
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629near future, the Add-Path extension to BGP may also solve MED oscillation while
630still allowing MED to be used as intended, by distributing "best-paths per
631neighbour AS". This would be at the cost of distributing at least as many
632routes to all speakers as a full-mesh iBGP would, if not more, while also
633imposing similar CPU overheads as the "Deterministic MED" feature at each
634Add-Path reflector.
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635
636More generally, the instability problems that MED can introduce on more
637complex, non-full-mesh, iBGP topologies may be avoided either by:
638
013f9762 639- Setting :clicmd:`bgp always-compare-med`, however this allows MED to be compared
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640 across values set by different neighbour ASes, which may not produce
641 coherent desirable results, of itself.
4b44467c 642- Effectively ignoring MED by setting MED to the same value (e.g.: 0) using
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643 :clicmd:`set metric METRIC` on all received routes, in combination with
644 setting :clicmd:`bgp always-compare-med` on all speakers. This is the simplest
42fc5d26
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645 and most performant way to avoid MED oscillation issues, where an AS is happy
646 not to allow neighbours to inject this problematic metric.
647
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648As MED is evaluated after the AS_PATH length check, another possible use for
649MED is for intra-AS steering of routes with equal AS_PATH length, as an
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650extension of the last case above. As MED is evaluated before IGP metric, this
651can allow cold-potato routing to be implemented to send traffic to preferred
652hand-offs with neighbours, rather than the closest hand-off according to the
653IGP metric.
654
655Note that even if action is taken to address the MED non-transitivity issues,
656other oscillations may still be possible. E.g., on IGP cost if iBGP and IGP
657topologies are at cross-purposes with each other - see the Flavel and Roughan
658paper above for an example. Hence the guideline that the iBGP topology should
659follow the IGP topology.
660
c3c5a71f 661.. index:: bgp deterministic-med
29adcd50 662.. clicmd:: bgp deterministic-med
42fc5d26 663
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664 Carry out route-selection in way that produces deterministic answers
665 locally, even in the face of MED and the lack of a well-defined order of
666 preference it can induce on routes. Without this option the preferred route
667 with MED may be determined largely by the order that routes were received
668 in.
42fc5d26 669
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670 Setting this option will have a performance cost that may be noticeable when
671 there are many routes for each destination. Currently in FRR it is
672 implemented in a way that scales poorly as the number of routes per
673 destination increases.
42fc5d26 674
c1a54c05 675 The default is that this option is not set.
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676
677Note that there are other sources of indeterminism in the route selection
678process, specifically, the preference for older and already selected routes
8fcedbd2 679from eBGP peers, :ref:`bgp-route-selection`.
42fc5d26 680
c3c5a71f 681.. index:: bgp always-compare-med
29adcd50 682.. clicmd:: bgp always-compare-med
42fc5d26 683
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684 Always compare the MED on routes, even when they were received from
685 different neighbouring ASes. Setting this option makes the order of
686 preference of routes more defined, and should eliminate MED induced
687 oscillations.
42fc5d26 688
c1a54c05 689 If using this option, it may also be desirable to use
9e146a81 690 :clicmd:`set metric METRIC` to set MED to 0 on routes received from external
c1a54c05 691 neighbours.
42fc5d26 692
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693 This option can be used, together with :clicmd:`set metric METRIC` to use
694 MED as an intra-AS metric to steer equal-length AS_PATH routes to, e.g.,
695 desired exit points.
42fc5d26 696
0efdf0fe 697.. _bgp-network:
42fc5d26 698
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699Networks
700--------
42fc5d26 701
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702.. index:: network A.B.C.D/M
703.. clicmd:: network A.B.C.D/M
42fc5d26 704
9eb95b3b 705 This command adds the announcement network.
c3c5a71f 706
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707 .. code-block:: frr
708
709 router bgp 1
710 address-family ipv4 unicast
711 network 10.0.0.0/8
712 exit-address-family
42fc5d26 713
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714 This configuration example says that network 10.0.0.0/8 will be
715 announced to all neighbors. Some vendors' routers don't advertise
716 routes if they aren't present in their IGP routing tables; `bgpd`
717 doesn't care about IGP routes when announcing its routes.
c3c5a71f 718
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719.. index:: no network A.B.C.D/M
720.. clicmd:: no network A.B.C.D/M
42fc5d26 721
8fcedbd2 722.. _bgp-route-aggregation:
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723
724Route Aggregation
725-----------------
726
5101fece 727.. _bgp-route-aggregation-ipv4:
728
729Route Aggregation-IPv4 Address Family
730^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
731
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732.. index:: aggregate-address A.B.C.D/M
733.. clicmd:: aggregate-address A.B.C.D/M
c3c5a71f 734
c1a54c05 735 This command specifies an aggregate address.
42fc5d26 736
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737.. index:: aggregate-address A.B.C.D/M route-map NAME
738.. clicmd:: aggregate-address A.B.C.D/M route-map NAME
739
740 Apply a route-map for an aggregated prefix.
741
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742.. index:: aggregate-address A.B.C.D/M as-set
743.. clicmd:: aggregate-address A.B.C.D/M as-set
42fc5d26 744
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745 This command specifies an aggregate address. Resulting routes include
746 AS set.
42fc5d26 747
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748.. index:: aggregate-address A.B.C.D/M summary-only
749.. clicmd:: aggregate-address A.B.C.D/M summary-only
c3c5a71f 750
d1e7591e 751 This command specifies an aggregate address. Aggregated routes will
c1a54c05 752 not be announce.
42fc5d26 753
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754.. index:: no aggregate-address A.B.C.D/M
755.. clicmd:: no aggregate-address A.B.C.D/M
ac2201bb 756
5101fece 757 This command removes an aggregate address.
758
759
ac2201bb 760 This configuration example setup the aggregate-address under
5101fece 761 ipv4 address-family.
762
763 .. code-block:: frr
764
765 router bgp 1
766 address-family ipv4 unicast
767 aggregate-address 10.0.0.0/8
768 aggregate-address 20.0.0.0/8 as-set
769 aggregate-address 40.0.0.0/8 summary-only
ac2201bb 770 aggregate-address 50.0.0.0/8 route-map aggr-rmap
5101fece 771 exit-address-family
772
773
774.. _bgp-route-aggregation-ipv6:
775
776Route Aggregation-IPv6 Address Family
777^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
778
779.. index:: aggregate-address X:X::X:X/M
780.. clicmd:: aggregate-address X:X::X:X/M
781
782 This command specifies an aggregate address.
783
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DA
784.. index:: aggregate-address X:X::X:X/M route-map NAME
785.. clicmd:: aggregate-address X:X::X:X/M route-map NAME
786
787 Apply a route-map for an aggregated prefix.
788
5101fece 789.. index:: aggregate-address X:X::X:X/M as-set
790.. clicmd:: aggregate-address X:X::X:X/M as-set
791
792 This command specifies an aggregate address. Resulting routes include
793 AS set.
794
795.. index:: aggregate-address X:X::X:X/M summary-only
796.. clicmd:: aggregate-address X:X::X:X/M summary-only
797
798 This command specifies an aggregate address. Aggregated routes will
799 not be announce.
800
801.. index:: no aggregate-address X:X::X:X/M
802.. clicmd:: no aggregate-address X:X::X:X/M
803
804 This command removes an aggregate address.
805
806
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807 This configuration example setup the aggregate-address under
808 ipv6 address-family.
5101fece 809
810 .. code-block:: frr
811
812 router bgp 1
813 address-family ipv6 unicast
814 aggregate-address 10::0/64
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DA
815 aggregate-address 20::0/64 as-set
816 aggregate-address 40::0/64 summary-only
817 aggregate-address 50::0/64 route-map aggr-rmap
5101fece 818 exit-address-family
c3c5a71f 819
8fcedbd2 820.. _bgp-redistribute-to-bgp:
42fc5d26 821
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822Redistribution
823--------------
42fc5d26 824
c3c5a71f 825.. index:: redistribute kernel
29adcd50 826.. clicmd:: redistribute kernel
42fc5d26 827
c1a54c05 828 Redistribute kernel route to BGP process.
42fc5d26 829
c3c5a71f 830.. index:: redistribute static
29adcd50 831.. clicmd:: redistribute static
42fc5d26 832
c1a54c05 833 Redistribute static route to BGP process.
42fc5d26 834
c3c5a71f 835.. index:: redistribute connected
29adcd50 836.. clicmd:: redistribute connected
42fc5d26 837
c1a54c05 838 Redistribute connected route to BGP process.
42fc5d26 839
c3c5a71f 840.. index:: redistribute rip
29adcd50 841.. clicmd:: redistribute rip
42fc5d26 842
c1a54c05 843 Redistribute RIP route to BGP process.
42fc5d26 844
c3c5a71f 845.. index:: redistribute ospf
29adcd50 846.. clicmd:: redistribute ospf
42fc5d26 847
c1a54c05 848 Redistribute OSPF route to BGP process.
42fc5d26 849
99ad55e0
DA
850.. index:: redistribute vnc
851.. clicmd:: redistribute vnc
42fc5d26 852
c1a54c05 853 Redistribute VNC routes to BGP process.
42fc5d26 854
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DA
855.. index:: redistribute vnc-direct
856.. clicmd:: redistribute vnc-direct
857
858 Redistribute VNC direct (not via zebra) routes to BGP process.
859
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860.. index:: update-delay MAX-DELAY
861.. clicmd:: update-delay MAX-DELAY
c3c5a71f 862
c1a54c05
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863.. index:: update-delay MAX-DELAY ESTABLISH-WAIT
864.. clicmd:: update-delay MAX-DELAY ESTABLISH-WAIT
c3c5a71f 865
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866 This feature is used to enable read-only mode on BGP process restart or when
867 BGP process is cleared using 'clear ip bgp \*'. When applicable, read-only
868 mode would begin as soon as the first peer reaches Established status and a
869 timer for max-delay seconds is started.
42fc5d26 870
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871 During this mode BGP doesn't run any best-path or generate any updates to its
872 peers. This mode continues until:
42fc5d26 873
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874 1. All the configured peers, except the shutdown peers, have sent explicit EOR
875 (End-Of-RIB) or an implicit-EOR. The first keep-alive after BGP has reached
876 Established is considered an implicit-EOR.
877 If the establish-wait optional value is given, then BGP will wait for
d1e7591e 878 peers to reach established from the beginning of the update-delay till the
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879 establish-wait period is over, i.e. the minimum set of established peers for
880 which EOR is expected would be peers established during the establish-wait
881 window, not necessarily all the configured neighbors.
882 2. max-delay period is over.
42fc5d26 883
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884 On hitting any of the above two conditions, BGP resumes the decision process
885 and generates updates to its peers.
42fc5d26 886
c1a54c05 887 Default max-delay is 0, i.e. the feature is off by default.
c3c5a71f 888
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889.. index:: table-map ROUTE-MAP-NAME
890.. clicmd:: table-map ROUTE-MAP-NAME
42fc5d26 891
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892 This feature is used to apply a route-map on route updates from BGP to
893 Zebra. All the applicable match operations are allowed, such as match on
894 prefix, next-hop, communities, etc. Set operations for this attach-point are
895 limited to metric and next-hop only. Any operation of this feature does not
896 affect BGPs internal RIB.
42fc5d26 897
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898 Supported for ipv4 and ipv6 address families. It works on multi-paths as
899 well, however, metric setting is based on the best-path only.
42fc5d26 900
8fcedbd2 901.. _bgp-peers:
42fc5d26 902
8fcedbd2
QY
903Peers
904-----
42fc5d26 905
8fcedbd2 906.. _bgp-defining-peers:
42fc5d26 907
8fcedbd2
QY
908Defining Peers
909^^^^^^^^^^^^^^
42fc5d26 910
c1a54c05
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911.. index:: neighbor PEER remote-as ASN
912.. clicmd:: neighbor PEER remote-as ASN
42fc5d26 913
c1a54c05 914 Creates a new neighbor whose remote-as is ASN. PEER can be an IPv4 address
9eb95b3b 915 or an IPv6 address or an interface to use for the connection.
76bd1499 916
9eb95b3b
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917 .. code-block:: frr
918
919 router bgp 1
920 neighbor 10.0.0.1 remote-as 2
76bd1499 921
c1a54c05 922 In this case my router, in AS-1, is trying to peer with AS-2 at 10.0.0.1.
76bd1499 923
c1a54c05 924 This command must be the first command used when configuring a neighbor. If
9eb95b3b 925 the remote-as is not specified, *bgpd* will complain like this: ::
76bd1499 926
c1a54c05 927 can't find neighbor 10.0.0.1
c3c5a71f 928
5413757f
DS
929.. index:: neighbor PEER remote-as internal
930.. clicmd:: neighbor PEER remote-as internal
931
932 Create a peer as you would when you specify an ASN, except that if the
933 peers ASN is different than mine as specified under the :clicmd:`router bgp ASN`
934 command the connection will be denied.
935
936.. index:: neighbor PEER remote-as external
937.. clicmd:: neighbor PEER remote-as external
938
939 Create a peer as you would when you specify an ASN, except that if the
940 peers ASN is the same as mine as specified under the :clicmd:`router bgp ASN`
941 command the connection will be denied.
42fc5d26 942
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DA
943.. index:: [no] bgp listen range <A.B.C.D/M|X:X::X:X/M> peer-group PGNAME
944.. clicmd:: [no] bgp listen range <A.B.C.D/M|X:X::X:X/M> peer-group PGNAME
d79e0e08
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945
946 Accept connections from any peers in the specified prefix. Configuration
947 from the specified peer-group is used to configure these peers.
948
949.. note::
950
951 When using BGP listen ranges, if the associated peer group has TCP MD5
952 authentication configured, your kernel must support this on prefixes. On
953 Linux, this support was added in kernel version 4.14. If your kernel does
954 not support this feature you will get a warning in the log file, and the
955 listen range will only accept connections from peers without MD5 configured.
956
957 Additionally, we have observed that when using this option at scale (several
958 hundred peers) the kernel may hit its option memory limit. In this situation
959 you will see error messages like:
960
961 ``bgpd: sockopt_tcp_signature: setsockopt(23): Cannot allocate memory``
962
963 In this case you need to increase the value of the sysctl
964 ``net.core.optmem_max`` to allow the kernel to allocate the necessary option
965 memory.
966
8fcedbd2 967.. _bgp-configuring-peers:
42fc5d26 968
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969Configuring Peers
970^^^^^^^^^^^^^^^^^
42fc5d26 971
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972.. index:: [no] neighbor PEER shutdown
973.. clicmd:: [no] neighbor PEER shutdown
c3c5a71f 974
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975 Shutdown the peer. We can delete the neighbor's configuration by
976 ``no neighbor PEER remote-as ASN`` but all configuration of the neighbor
977 will be deleted. When you want to preserve the configuration, but want to
978 drop the BGP peer, use this syntax.
c3c5a71f 979
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980.. index:: [no] neighbor PEER disable-connected-check
981.. clicmd:: [no] neighbor PEER disable-connected-check
c3c5a71f 982
c0868e8b
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983 Allow peerings between directly connected eBGP peers using loopback
984 addresses.
c3c5a71f 985
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986.. index:: [no] neighbor PEER ebgp-multihop
987.. clicmd:: [no] neighbor PEER ebgp-multihop
42fc5d26 988
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989.. index:: [no] neighbor PEER description ...
990.. clicmd:: [no] neighbor PEER description ...
42fc5d26 991
c1a54c05 992 Set description of the peer.
42fc5d26 993
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994.. index:: [no] neighbor PEER version VERSION
995.. clicmd:: [no] neighbor PEER version VERSION
42fc5d26 996
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997 Set up the neighbor's BGP version. `version` can be `4`, `4+` or `4-`. BGP
998 version `4` is the default value used for BGP peering. BGP version `4+`
999 means that the neighbor supports Multiprotocol Extensions for BGP-4. BGP
1000 version `4-` is similar but the neighbor speaks the old Internet-Draft
1001 revision 00's Multiprotocol Extensions for BGP-4. Some routing software is
1002 still using this version.
42fc5d26 1003
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1004.. index:: [no] neighbor PEER interface IFNAME
1005.. clicmd:: [no] neighbor PEER interface IFNAME
42fc5d26 1006
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1007 When you connect to a BGP peer over an IPv6 link-local address, you have to
1008 specify the IFNAME of the interface used for the connection. To specify
1009 IPv4 session addresses, see the ``neighbor PEER update-source`` command
1010 below.
42fc5d26 1011
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1012 This command is deprecated and may be removed in a future release. Its use
1013 should be avoided.
42fc5d26 1014
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1015.. index:: [no] neighbor PEER next-hop-self [all]
1016.. clicmd:: [no] neighbor PEER next-hop-self [all]
42fc5d26 1017
c1a54c05
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1018 This command specifies an announced route's nexthop as being equivalent to
1019 the address of the bgp router if it is learned via eBGP. If the optional
d1e7591e 1020 keyword `all` is specified the modification is done also for routes learned
c1a54c05 1021 via iBGP.
42fc5d26 1022
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1023.. index:: [no] neighbor PEER update-source <IFNAME|ADDRESS>
1024.. clicmd:: [no] neighbor PEER update-source <IFNAME|ADDRESS>
42fc5d26 1025
c1a54c05
QY
1026 Specify the IPv4 source address to use for the :abbr:`BGP` session to this
1027 neighbour, may be specified as either an IPv4 address directly or as an
1028 interface name (in which case the *zebra* daemon MUST be running in order
9eb95b3b
QY
1029 for *bgpd* to be able to retrieve interface state).
1030
1031 .. code-block:: frr
42fc5d26 1032
c1a54c05
QY
1033 router bgp 64555
1034 neighbor foo update-source 192.168.0.1
1035 neighbor bar update-source lo0
42fc5d26 1036
42fc5d26 1037
c0868e8b
QY
1038.. index:: [no] neighbor PEER default-originate
1039.. clicmd:: [no] neighbor PEER default-originate
42fc5d26 1040
4da7fda3
QY
1041 *bgpd*'s default is to not announce the default route (0.0.0.0/0) even if it
1042 is in routing table. When you want to announce default routes to the peer,
1043 use this command.
42fc5d26 1044
c1a54c05
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1045.. index:: neighbor PEER port PORT
1046.. clicmd:: neighbor PEER port PORT
42fc5d26 1047
c1a54c05
QY
1048.. index:: neighbor PEER send-community
1049.. clicmd:: neighbor PEER send-community
42fc5d26 1050
c0868e8b
QY
1051.. index:: [no] neighbor PEER weight WEIGHT
1052.. clicmd:: [no] neighbor PEER weight WEIGHT
42fc5d26 1053
c1a54c05 1054 This command specifies a default `weight` value for the neighbor's routes.
42fc5d26 1055
c0868e8b
QY
1056.. index:: [no] neighbor PEER maximum-prefix NUMBER
1057.. clicmd:: [no] neighbor PEER maximum-prefix NUMBER
42fc5d26 1058
886026c8
QY
1059 Sets a maximum number of prefixes we can receive from a given peer. If this
1060 number is exceeded, the BGP session will be destroyed.
1061
1062 In practice, it is generally preferable to use a prefix-list to limit what
1063 prefixes are received from the peer instead of using this knob. Tearing down
1064 the BGP session when a limit is exceeded is far more destructive than merely
1065 rejecting undesired prefixes. The prefix-list method is also much more
1066 granular and offers much smarter matching criterion than number of received
1067 prefixes, making it more suited to implementing policy.
1068
1069.. index:: [no] neighbor PEER local-as AS-NUMBER [no-prepend] [replace-as]
1070.. clicmd:: [no] neighbor PEER local-as AS-NUMBER [no-prepend] [replace-as]
42fc5d26 1071
c1a54c05
QY
1072 Specify an alternate AS for this BGP process when interacting with the
1073 specified peer. With no modifiers, the specified local-as is prepended to
1074 the received AS_PATH when receiving routing updates from the peer, and
1075 prepended to the outgoing AS_PATH (after the process local AS) when
1076 transmitting local routes to the peer.
42fc5d26 1077
c1a54c05
QY
1078 If the no-prepend attribute is specified, then the supplied local-as is not
1079 prepended to the received AS_PATH.
c3c5a71f 1080
c1a54c05
QY
1081 If the replace-as attribute is specified, then only the supplied local-as is
1082 prepended to the AS_PATH when transmitting local-route updates to this peer.
c3c5a71f 1083
c1a54c05 1084 Note that replace-as can only be specified if no-prepend is.
c3c5a71f 1085
c1a54c05 1086 This command is only allowed for eBGP peers.
c3c5a71f 1087
c0868e8b
QY
1088.. index:: [no] neighbor PEER ttl-security hops NUMBER
1089.. clicmd:: [no] neighbor PEER ttl-security hops NUMBER
c3c5a71f 1090
c1a54c05
QY
1091 This command enforces Generalized TTL Security Mechanism (GTSM), as
1092 specified in RFC 5082. With this command, only neighbors that are the
1093 specified number of hops away will be allowed to become neighbors. This
d1e7591e 1094 command is mutually exclusive with *ebgp-multihop*.
42fc5d26 1095
19f2b5e8
DS
1096.. index:: [no] neighbor PEER capability extended-nexthop
1097.. clicmd:: [no] neighbor PEER capability extended-nexthop
1098
1099 Allow bgp to negotiate the extended-nexthop capability with it's peer.
1100 If you are peering over a v6 LL address then this capability is turned
1101 on automatically. If you are peering over a v6 Global Address then
1102 turning on this command will allow BGP to install v4 routes with
1103 v6 nexthops if you do not have v4 configured on interfaces.
1104
eb938189
DS
1105.. index:: [no] bgp fast-external-failover
1106.. clicmd:: [no] bgp fast-external-failover
1107
1108 This command causes bgp to not take down ebgp peers immediately
1109 when a link flaps. `bgp fast-external-failover` is the default
1110 and will not be displayed as part of a `show run`. The no form
1111 of the command turns off this ability.
1112
bc132029
DS
1113.. index:: [no] bgp default ipv4-unicast
1114.. clicmd:: [no] bgp default ipv4-unicast
1115
1116 This command allows the user to specify that v4 peering is turned
1117 on by default or not. This command defaults to on and is not displayed.
1118 The `no bgp default ipv4-unicast` form of the command is displayed.
1119
e10dda57
DS
1120.. index:: [no] neighbor PEER advertisement-interval (0-600)
1121.. clicmd:: [no] neighbor PEER advertisement-interval (0-600)
1122
1123 Setup the minimum route advertisement interval(mrai) for the
1124 peer in question. This number is between 0 and 600 seconds,
1125 with the default advertisement interval being 0.
1126
8fcedbd2 1127.. _bgp-peer-filtering:
42fc5d26 1128
8fcedbd2
QY
1129Peer Filtering
1130^^^^^^^^^^^^^^
42fc5d26 1131
c1a54c05
QY
1132.. index:: neighbor PEER distribute-list NAME [in|out]
1133.. clicmd:: neighbor PEER distribute-list NAME [in|out]
42fc5d26 1134
c1a54c05
QY
1135 This command specifies a distribute-list for the peer. `direct` is
1136 ``in`` or ``out``.
42fc5d26 1137
c3c5a71f 1138.. index:: neighbor PEER prefix-list NAME [in|out]
29adcd50 1139.. clicmd:: neighbor PEER prefix-list NAME [in|out]
42fc5d26 1140
c1a54c05 1141.. index:: neighbor PEER filter-list NAME [in|out]
29adcd50 1142.. clicmd:: neighbor PEER filter-list NAME [in|out]
42fc5d26 1143
c1a54c05
QY
1144.. index:: neighbor PEER route-map NAME [in|out]
1145.. clicmd:: neighbor PEER route-map NAME [in|out]
42fc5d26 1146
c1a54c05 1147 Apply a route-map on the neighbor. `direct` must be `in` or `out`.
42fc5d26 1148
c3c5a71f 1149.. index:: bgp route-reflector allow-outbound-policy
29adcd50 1150.. clicmd:: bgp route-reflector allow-outbound-policy
42fc5d26 1151
c1a54c05
QY
1152 By default, attribute modification via route-map policy out is not reflected
1153 on reflected routes. This option allows the modifications to be reflected as
1154 well. Once enabled, it affects all reflected routes.
42fc5d26 1155
583a9fd4
RZ
1156.. index:: [no] neighbor PEER sender-as-path-loop-detection
1157.. clicmd:: [no] neighbor PEER sender-as-path-loop-detection
1158
1159 Enable the detection of sender side AS path loops and filter the
1160 bad routes before they are sent.
1161
1162 This setting is disabled by default.
1163
0efdf0fe 1164.. _bgp-peer-group:
42fc5d26 1165
8fcedbd2
QY
1166Peer Groups
1167^^^^^^^^^^^
42fc5d26 1168
199ad5c4
LB
1169Peer groups are used to help improve scaling by generating the same
1170update information to all members of a peer group. Note that this means
1171that the routes generated by a member of a peer group will be sent back
1172to that originating peer with the originator identifier attribute set to
1173indicated the originating peer. All peers not associated with a
1174specific peer group are treated as belonging to a default peer group,
1175and will share updates.
1176
c1a54c05
QY
1177.. index:: neighbor WORD peer-group
1178.. clicmd:: neighbor WORD peer-group
42fc5d26 1179
c1a54c05 1180 This command defines a new peer group.
42fc5d26 1181
d7b9898c
DA
1182.. index:: neighbor PEER peer-group PGNAME
1183.. clicmd:: neighbor PEER peer-group PGNAME
c3c5a71f 1184
c1a54c05 1185 This command bind specific peer to peer group WORD.
42fc5d26 1186
199ad5c4
LB
1187.. index:: neighbor PEER solo
1188.. clicmd:: neighbor PEER solo
1189
1190 This command is used to indicate that routes advertised by the peer
1191 should not be reflected back to the peer. This command only is only
1192 meaningful when there is a single peer defined in the peer-group.
1193
8fcedbd2
QY
1194Capability Negotiation
1195^^^^^^^^^^^^^^^^^^^^^^
42fc5d26 1196
8fcedbd2
QY
1197.. index:: neighbor PEER strict-capability-match
1198.. clicmd:: neighbor PEER strict-capability-match
42fc5d26 1199
8fcedbd2
QY
1200.. index:: no neighbor PEER strict-capability-match
1201.. clicmd:: no neighbor PEER strict-capability-match
c1a54c05 1202
8fcedbd2
QY
1203 Strictly compares remote capabilities and local capabilities. If
1204 capabilities are different, send Unsupported Capability error then reset
1205 connection.
42fc5d26 1206
8fcedbd2
QY
1207 You may want to disable sending Capability Negotiation OPEN message optional
1208 parameter to the peer when remote peer does not implement Capability
1209 Negotiation. Please use *dont-capability-negotiate* command to disable the
1210 feature.
42fc5d26 1211
7cdc9530
DS
1212.. index:: [no] neighbor PEER dont-capability-negotiate
1213.. clicmd:: [no] neighbor PEER dont-capability-negotiate
42fc5d26 1214
8fcedbd2
QY
1215 Suppress sending Capability Negotiation as OPEN message optional parameter
1216 to the peer. This command only affects the peer is configured other than
1217 IPv4 unicast configuration.
42fc5d26 1218
8fcedbd2
QY
1219 When remote peer does not have capability negotiation feature, remote peer
1220 will not send any capabilities at all. In that case, bgp configures the peer
1221 with configured capabilities.
42fc5d26 1222
8fcedbd2
QY
1223 You may prefer locally configured capabilities more than the negotiated
1224 capabilities even though remote peer sends capabilities. If the peer is
1225 configured by *override-capability*, *bgpd* ignores received capabilities
1226 then override negotiated capabilities with configured values.
42fc5d26 1227
7cdc9530
DS
1228 Additionally the operator should be reminded that this feature fundamentally
1229 disables the ability to use widely deployed BGP features. BGP unnumbered,
1230 hostname support, AS4, Addpath, Route Refresh, ORF, Dynamic Capabilities,
1231 and graceful restart.
1232
8fcedbd2
QY
1233.. index:: neighbor PEER override-capability
1234.. clicmd:: neighbor PEER override-capability
42fc5d26 1235
8fcedbd2
QY
1236.. index:: no neighbor PEER override-capability
1237.. clicmd:: no neighbor PEER override-capability
c1a54c05 1238
8fcedbd2
QY
1239 Override the result of Capability Negotiation with local configuration.
1240 Ignore remote peer's capability value.
42fc5d26 1241
8fcedbd2 1242.. _bgp-as-path-access-lists:
42fc5d26 1243
8fcedbd2
QY
1244AS Path Access Lists
1245--------------------
42fc5d26
QY
1246
1247AS path access list is user defined AS path.
1248
a64e0ee5
DA
1249.. index:: bgp as-path access-list WORD permit|deny LINE
1250.. clicmd:: bgp as-path access-list WORD permit|deny LINE
42fc5d26 1251
c1a54c05 1252 This command defines a new AS path access list.
42fc5d26 1253
a64e0ee5
DA
1254.. index:: no bgp as-path access-list WORD
1255.. clicmd:: no bgp as-path access-list WORD
42fc5d26 1256
a64e0ee5
DA
1257.. index:: no bgp as-path access-list WORD permit|deny LINE
1258.. clicmd:: no bgp as-path access-list WORD permit|deny LINE
42fc5d26 1259
8fcedbd2 1260.. _bgp-using-as-path-in-route-map:
42fc5d26
QY
1261
1262Using AS Path in Route Map
1263--------------------------
1264
eb1f303d
DS
1265.. index:: [no] match as-path WORD
1266.. clicmd:: [no] match as-path WORD
42fc5d26 1267
eb1f303d
DS
1268 For a given as-path, WORD, match it on the BGP as-path given for the prefix
1269 and if it matches do normal route-map actions. The no form of the command
1270 removes this match from the route-map.
42fc5d26 1271
eb1f303d
DS
1272.. index:: [no] set as-path prepend AS-PATH
1273.. clicmd:: [no] set as-path prepend AS-PATH
42fc5d26 1274
eb1f303d
DS
1275 Prepend the given string of AS numbers to the AS_PATH of the BGP path's NLRI.
1276 The no form of this command removes this set operation from the route-map.
42fc5d26 1277
eb1f303d
DS
1278.. index:: [no] set as-path prepend last-as NUM
1279.. clicmd:: [no] set as-path prepend last-as NUM
c1a54c05
QY
1280
1281 Prepend the existing last AS number (the leftmost ASN) to the AS_PATH.
eb1f303d 1282 The no form of this command removes this set operation from the route-map.
42fc5d26 1283
0efdf0fe 1284.. _bgp-communities-attribute:
42fc5d26 1285
8fcedbd2
QY
1286Communities Attribute
1287---------------------
42fc5d26 1288
8fcedbd2 1289The BGP communities attribute is widely used for implementing policy routing.
c1a54c05
QY
1290Network operators can manipulate BGP communities attribute based on their
1291network policy. BGP communities attribute is defined in :rfc:`1997` and
1292:rfc:`1998`. It is an optional transitive attribute, therefore local policy can
1293travel through different autonomous system.
1294
8fcedbd2
QY
1295The communities attribute is a set of communities values. Each community value
1296is 4 octet long. The following format is used to define the community value.
c1a54c05 1297
8fcedbd2 1298``AS:VAL``
c1a54c05
QY
1299 This format represents 4 octet communities value. ``AS`` is high order 2
1300 octet in digit format. ``VAL`` is low order 2 octet in digit format. This
1301 format is useful to define AS oriented policy value. For example,
1302 ``7675:80`` can be used when AS 7675 wants to pass local policy value 80 to
1303 neighboring peer.
1304
8fcedbd2
QY
1305``internet``
1306 ``internet`` represents well-known communities value 0.
c1a54c05 1307
cae770d3
C
1308``graceful-shutdown``
1309 ``graceful-shutdown`` represents well-known communities value
1310 ``GRACEFUL_SHUTDOWN`` ``0xFFFF0000`` ``65535:0``. :rfc:`8326` implements
1311 the purpose Graceful BGP Session Shutdown to reduce the amount of
56f0bea7 1312 lost traffic when taking BGP sessions down for maintenance. The use
cae770d3
C
1313 of the community needs to be supported from your peers side to
1314 actually have any effect.
1315
1316``accept-own``
1317 ``accept-own`` represents well-known communities value ``ACCEPT_OWN``
1318 ``0xFFFF0001`` ``65535:1``. :rfc:`7611` implements a way to signal
1319 to a router to accept routes with a local nexthop address. This
1320 can be the case when doing policing and having traffic having a
1321 nexthop located in another VRF but still local interface to the
1322 router. It is recommended to read the RFC for full details.
1323
1324``route-filter-translated-v4``
1325 ``route-filter-translated-v4`` represents well-known communities value
1326 ``ROUTE_FILTER_TRANSLATED_v4`` ``0xFFFF0002`` ``65535:2``.
1327
1328``route-filter-v4``
1329 ``route-filter-v4`` represents well-known communities value
1330 ``ROUTE_FILTER_v4`` ``0xFFFF0003`` ``65535:3``.
1331
1332``route-filter-translated-v6``
1333 ``route-filter-translated-v6`` represents well-known communities value
1334 ``ROUTE_FILTER_TRANSLATED_v6`` ``0xFFFF0004`` ``65535:4``.
1335
1336``route-filter-v6``
1337 ``route-filter-v6`` represents well-known communities value
1338 ``ROUTE_FILTER_v6`` ``0xFFFF0005`` ``65535:5``.
1339
1340``llgr-stale``
1341 ``llgr-stale`` represents well-known communities value ``LLGR_STALE``
1342 ``0xFFFF0006`` ``65535:6``.
56f0bea7 1343 Assigned and intended only for use with routers supporting the
cae770d3 1344 Long-lived Graceful Restart Capability as described in
49606d58 1345 [Draft-IETF-uttaro-idr-bgp-persistence]_.
56f0bea7 1346 Routers receiving routes with this community may (depending on
cae770d3
C
1347 implementation) choose allow to reject or modify routes on the
1348 presence or absence of this community.
1349
1350``no-llgr``
1351 ``no-llgr`` represents well-known communities value ``NO_LLGR``
1352 ``0xFFFF0007`` ``65535:7``.
56f0bea7 1353 Assigned and intended only for use with routers supporting the
cae770d3 1354 Long-lived Graceful Restart Capability as described in
49606d58 1355 [Draft-IETF-uttaro-idr-bgp-persistence]_.
56f0bea7 1356 Routers receiving routes with this community may (depending on
cae770d3
C
1357 implementation) choose allow to reject or modify routes on the
1358 presence or absence of this community.
1359
1360``accept-own-nexthop``
1361 ``accept-own-nexthop`` represents well-known communities value
1362 ``accept-own-nexthop`` ``0xFFFF0008`` ``65535:8``.
49606d58 1363 [Draft-IETF-agrewal-idr-accept-own-nexthop]_ describes
cae770d3
C
1364 how to tag and label VPN routes to be able to send traffic between VRFs
1365 via an internal layer 2 domain on the same PE device. Refer to
49606d58 1366 [Draft-IETF-agrewal-idr-accept-own-nexthop]_ for full details.
cae770d3
C
1367
1368``blackhole``
1369 ``blackhole`` represents well-known communities value ``BLACKHOLE``
1370 ``0xFFFF029A`` ``65535:666``. :rfc:`7999` documents sending prefixes to
1371 EBGP peers and upstream for the purpose of blackholing traffic.
1372 Prefixes tagged with the this community should normally not be
1373 re-advertised from neighbors of the originating network. It is
1374 recommended upon receiving prefixes tagged with this community to
1375 add ``NO_EXPORT`` and ``NO_ADVERTISE``.
1376
8fcedbd2 1377``no-export``
c1a54c05
QY
1378 ``no-export`` represents well-known communities value ``NO_EXPORT``
1379 ``0xFFFFFF01``. All routes carry this value must not be advertised to
1380 outside a BGP confederation boundary. If neighboring BGP peer is part of BGP
1381 confederation, the peer is considered as inside a BGP confederation
1382 boundary, so the route will be announced to the peer.
1383
8fcedbd2 1384``no-advertise``
c1a54c05
QY
1385 ``no-advertise`` represents well-known communities value ``NO_ADVERTISE``
1386 ``0xFFFFFF02``. All routes carry this value must not be advertise to other
1387 BGP peers.
1388
8fcedbd2 1389``local-AS``
c1a54c05
QY
1390 ``local-AS`` represents well-known communities value ``NO_EXPORT_SUBCONFED``
1391 ``0xFFFFFF03``. All routes carry this value must not be advertised to
1392 external BGP peers. Even if the neighboring router is part of confederation,
1393 it is considered as external BGP peer, so the route will not be announced to
1394 the peer.
1395
cae770d3
C
1396``no-peer``
1397 ``no-peer`` represents well-known communities value ``NOPEER``
1398 ``0xFFFFFF04`` ``65535:65284``. :rfc:`3765` is used to communicate to
1399 another network how the originating network want the prefix propagated.
1400
aa9eafa4
QY
1401When the communities attribute is received duplicate community values in the
1402attribute are ignored and value is sorted in numerical order.
42fc5d26 1403
49606d58
PG
1404.. [Draft-IETF-uttaro-idr-bgp-persistence] <https://tools.ietf.org/id/draft-uttaro-idr-bgp-persistence-04.txt>
1405.. [Draft-IETF-agrewal-idr-accept-own-nexthop] <https://tools.ietf.org/id/draft-agrewal-idr-accept-own-nexthop-00.txt>
1406
0efdf0fe 1407.. _bgp-community-lists:
42fc5d26 1408
8fcedbd2
QY
1409Community Lists
1410^^^^^^^^^^^^^^^
aa9eafa4
QY
1411Community lists are user defined lists of community attribute values. These
1412lists can be used for matching or manipulating the communities attribute in
1413UPDATE messages.
42fc5d26 1414
aa9eafa4 1415There are two types of community list:
c1a54c05 1416
aa9eafa4 1417standard
56f0bea7 1418 This type accepts an explicit value for the attribute.
aa9eafa4
QY
1419
1420expanded
1421 This type accepts a regular expression. Because the regex must be
1422 interpreted on each use expanded community lists are slower than standard
1423 lists.
42fc5d26 1424
a64e0ee5
DA
1425.. index:: bgp community-list standard NAME permit|deny COMMUNITY
1426.. clicmd:: bgp community-list standard NAME permit|deny COMMUNITY
42fc5d26 1427
aa9eafa4
QY
1428 This command defines a new standard community list. ``COMMUNITY`` is
1429 communities value. The ``COMMUNITY`` is compiled into community structure.
1430 We can define multiple community list under same name. In that case match
1431 will happen user defined order. Once the community list matches to
1432 communities attribute in BGP updates it return permit or deny by the
1433 community list definition. When there is no matched entry, deny will be
1434 returned. When ``COMMUNITY`` is empty it matches to any routes.
42fc5d26 1435
a64e0ee5
DA
1436.. index:: bgp community-list expanded NAME permit|deny COMMUNITY
1437.. clicmd:: bgp community-list expanded NAME permit|deny COMMUNITY
42fc5d26 1438
aa9eafa4
QY
1439 This command defines a new expanded community list. ``COMMUNITY`` is a
1440 string expression of communities attribute. ``COMMUNITY`` can be a regular
1441 expression (:ref:`bgp-regular-expressions`) to match the communities
47f47873
PG
1442 attribute in BGP updates. The expanded community is only used to filter,
1443 not `set` actions.
42fc5d26 1444
aa9eafa4
QY
1445.. deprecated:: 5.0
1446 It is recommended to use the more explicit versions of this command.
42fc5d26 1447
a64e0ee5
DA
1448.. index:: bgp community-list NAME permit|deny COMMUNITY
1449.. clicmd:: bgp community-list NAME permit|deny COMMUNITY
aa9eafa4
QY
1450
1451 When the community list type is not specified, the community list type is
1452 automatically detected. If ``COMMUNITY`` can be compiled into communities
1453 attribute, the community list is defined as a standard community list.
1454 Otherwise it is defined as an expanded community list. This feature is left
1455 for backward compatibility. Use of this feature is not recommended.
42fc5d26 1456
42fc5d26 1457
a64e0ee5
DA
1458.. index:: no bgp community-list [standard|expanded] NAME
1459.. clicmd:: no bgp community-list [standard|expanded] NAME
42fc5d26 1460
aa9eafa4
QY
1461 Deletes the community list specified by ``NAME``. All community lists share
1462 the same namespace, so it's not necessary to specify ``standard`` or
1463 ``expanded``; these modifiers are purely aesthetic.
42fc5d26 1464
a64e0ee5
DA
1465.. index:: show bgp community-list [NAME]
1466.. clicmd:: show bgp community-list [NAME]
42fc5d26 1467
aa9eafa4
QY
1468 Displays community list information. When ``NAME`` is specified the
1469 specified community list's information is shown.
c3c5a71f 1470
c1a54c05 1471 ::
76bd1499 1472
a64e0ee5 1473 # show bgp community-list
c1a54c05
QY
1474 Named Community standard list CLIST
1475 permit 7675:80 7675:100 no-export
1476 deny internet
1477 Named Community expanded list EXPAND
1478 permit :
76bd1499 1479
a64e0ee5 1480 # show bgp community-list CLIST
c1a54c05
QY
1481 Named Community standard list CLIST
1482 permit 7675:80 7675:100 no-export
1483 deny internet
42fc5d26 1484
42fc5d26 1485
8fcedbd2 1486.. _bgp-numbered-community-lists:
42fc5d26 1487
8fcedbd2
QY
1488Numbered Community Lists
1489^^^^^^^^^^^^^^^^^^^^^^^^
42fc5d26
QY
1490
1491When number is used for BGP community list name, the number has
c3c5a71f
QY
1492special meanings. Community list number in the range from 1 and 99 is
1493standard community list. Community list number in the range from 100
1494to 199 is expanded community list. These community lists are called
1495as numbered community lists. On the other hand normal community lists
42fc5d26
QY
1496is called as named community lists.
1497
a64e0ee5
DA
1498.. index:: bgp community-list (1-99) permit|deny COMMUNITY
1499.. clicmd:: bgp community-list (1-99) permit|deny COMMUNITY
42fc5d26 1500
aa9eafa4
QY
1501 This command defines a new community list. The argument to (1-99) defines
1502 the list identifier.
42fc5d26 1503
a64e0ee5
DA
1504.. index:: bgp community-list (100-199) permit|deny COMMUNITY
1505.. clicmd:: bgp community-list (100-199) permit|deny COMMUNITY
42fc5d26 1506
aa9eafa4
QY
1507 This command defines a new expanded community list. The argument to
1508 (100-199) defines the list identifier.
42fc5d26 1509
8fcedbd2 1510.. _bgp-using-communities-in-route-map:
42fc5d26 1511
8fcedbd2
QY
1512Using Communities in Route Maps
1513^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
42fc5d26 1514
aa9eafa4
QY
1515In :ref:`route-map` we can match on or set the BGP communities attribute. Using
1516this feature network operator can implement their network policy based on BGP
1517communities attribute.
42fc5d26 1518
aa9eafa4 1519The ollowing commands can be used in route maps:
42fc5d26 1520
aa9eafa4
QY
1521.. index:: match community WORD exact-match [exact-match]
1522.. clicmd:: match community WORD exact-match [exact-match]
42fc5d26 1523
c1a54c05
QY
1524 This command perform match to BGP updates using community list WORD. When
1525 the one of BGP communities value match to the one of communities value in
d1e7591e 1526 community list, it is match. When `exact-match` keyword is specified, match
c1a54c05
QY
1527 happen only when BGP updates have completely same communities value
1528 specified in the community list.
42fc5d26 1529
aa9eafa4
QY
1530.. index:: set community <none|COMMUNITY> additive
1531.. clicmd:: set community <none|COMMUNITY> additive
42fc5d26 1532
aa9eafa4
QY
1533 This command sets the community value in BGP updates. If the attribute is
1534 already configured, the newly provided value replaces the old one unless the
1535 ``additive`` keyword is specified, in which case the new value is appended
1536 to the existing value.
42fc5d26 1537
aa9eafa4
QY
1538 If ``none`` is specified as the community value, the communities attribute
1539 is not sent.
42fc5d26 1540
47f47873
PG
1541 It is not possible to set an expanded community list.
1542
c1a54c05 1543.. index:: set comm-list WORD delete
29adcd50 1544.. clicmd:: set comm-list WORD delete
c1a54c05 1545
aa9eafa4
QY
1546 This command remove communities value from BGP communities attribute. The
1547 ``word`` is community list name. When BGP route's communities value matches
1548 to the community list ``word``, the communities value is removed. When all
1549 of communities value is removed eventually, the BGP update's communities
1550 attribute is completely removed.
42fc5d26 1551
8fcedbd2 1552.. _bgp-communities-example:
c1a54c05 1553
8fcedbd2
QY
1554Example Configuration
1555^^^^^^^^^^^^^^^^^^^^^
9eb95b3b 1556
8fcedbd2
QY
1557The following configuration is exemplary of the most typical usage of BGP
1558communities attribute. In the example, AS 7675 provides an upstream Internet
1559connection to AS 100. When the following configuration exists in AS 7675, the
1560network operator of AS 100 can set local preference in AS 7675 network by
1561setting BGP communities attribute to the updates.
9eb95b3b
QY
1562
1563.. code-block:: frr
c1a54c05
QY
1564
1565 router bgp 7675
1566 neighbor 192.168.0.1 remote-as 100
1567 address-family ipv4 unicast
1568 neighbor 192.168.0.1 route-map RMAP in
1569 exit-address-family
1570 !
a64e0ee5
DA
1571 bgp community-list 70 permit 7675:70
1572 bgp community-list 70 deny
1573 bgp community-list 80 permit 7675:80
1574 bgp community-list 80 deny
1575 bgp community-list 90 permit 7675:90
1576 bgp community-list 90 deny
c1a54c05
QY
1577 !
1578 route-map RMAP permit 10
1579 match community 70
1580 set local-preference 70
1581 !
1582 route-map RMAP permit 20
1583 match community 80
1584 set local-preference 80
1585 !
1586 route-map RMAP permit 30
1587 match community 90
1588 set local-preference 90
c3c5a71f 1589
42fc5d26 1590
8fcedbd2
QY
1591The following configuration announces ``10.0.0.0/8`` from AS 100 to AS 7675.
1592The route has communities value ``7675:80`` so when above configuration exists
1593in AS 7675, the announced routes' local preference value will be set to 80.
9eb95b3b
QY
1594
1595.. code-block:: frr
c1a54c05
QY
1596
1597 router bgp 100
1598 network 10.0.0.0/8
1599 neighbor 192.168.0.2 remote-as 7675
1600 address-family ipv4 unicast
1601 neighbor 192.168.0.2 route-map RMAP out
1602 exit-address-family
1603 !
1604 ip prefix-list PLIST permit 10.0.0.0/8
1605 !
1606 route-map RMAP permit 10
1607 match ip address prefix-list PLIST
1608 set community 7675:80
c3c5a71f 1609
42fc5d26 1610
8fcedbd2
QY
1611The following configuration is an example of BGP route filtering using
1612communities attribute. This configuration only permit BGP routes which has BGP
1613communities value ``0:80`` or ``0:90``. The network operator can set special
1614internal communities value at BGP border router, then limit the BGP route
1615announcements into the internal network.
9eb95b3b
QY
1616
1617.. code-block:: frr
42fc5d26 1618
c1a54c05
QY
1619 router bgp 7675
1620 neighbor 192.168.0.1 remote-as 100
1621 address-family ipv4 unicast
1622 neighbor 192.168.0.1 route-map RMAP in
1623 exit-address-family
1624 !
a64e0ee5 1625 bgp community-list 1 permit 0:80 0:90
c1a54c05
QY
1626 !
1627 route-map RMAP permit in
1628 match community 1
c3c5a71f 1629
42fc5d26 1630
8fcedbd2
QY
1631The following example filters BGP routes which have a community value of
1632``1:1``. When there is no match community-list returns ``deny``. To avoid
1633filtering all routes, a ``permit`` line is set at the end of the
1634community-list.
9eb95b3b
QY
1635
1636.. code-block:: frr
42fc5d26 1637
c1a54c05
QY
1638 router bgp 7675
1639 neighbor 192.168.0.1 remote-as 100
1640 address-family ipv4 unicast
1641 neighbor 192.168.0.1 route-map RMAP in
1642 exit-address-family
1643 !
a64e0ee5
DA
1644 bgp community-list standard FILTER deny 1:1
1645 bgp community-list standard FILTER permit
c1a54c05
QY
1646 !
1647 route-map RMAP permit 10
1648 match community FILTER
c3c5a71f 1649
42fc5d26 1650
8fcedbd2
QY
1651The communities value keyword ``internet`` has special meanings in standard
1652community lists. In the below example ``internet`` matches all BGP routes even
1653if the route does not have communities attribute at all. So community list
1654``INTERNET`` is the same as ``FILTER`` in the previous example.
9eb95b3b
QY
1655
1656.. code-block:: frr
42fc5d26 1657
a64e0ee5
DA
1658 bgp community-list standard INTERNET deny 1:1
1659 bgp community-list standard INTERNET permit internet
c3c5a71f 1660
42fc5d26 1661
8fcedbd2
QY
1662The following configuration is an example of communities value deletion. With
1663this configuration the community values ``100:1`` and ``100:2`` are removed
1664from BGP updates. For communities value deletion, only ``permit``
1665community-list is used. ``deny`` community-list is ignored.
9eb95b3b
QY
1666
1667.. code-block:: frr
42fc5d26 1668
c1a54c05
QY
1669 router bgp 7675
1670 neighbor 192.168.0.1 remote-as 100
1671 address-family ipv4 unicast
1672 neighbor 192.168.0.1 route-map RMAP in
1673 exit-address-family
1674 !
a64e0ee5 1675 bgp community-list standard DEL permit 100:1 100:2
c1a54c05
QY
1676 !
1677 route-map RMAP permit 10
1678 set comm-list DEL delete
c3c5a71f 1679
42fc5d26 1680
0efdf0fe 1681.. _bgp-extended-communities-attribute:
42fc5d26 1682
8fcedbd2
QY
1683Extended Communities Attribute
1684^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
42fc5d26 1685
c1a54c05
QY
1686BGP extended communities attribute is introduced with MPLS VPN/BGP technology.
1687MPLS VPN/BGP expands capability of network infrastructure to provide VPN
1688functionality. At the same time it requires a new framework for policy routing.
1689With BGP Extended Communities Attribute we can use Route Target or Site of
1690Origin for implementing network policy for MPLS VPN/BGP.
42fc5d26 1691
c1a54c05
QY
1692BGP Extended Communities Attribute is similar to BGP Communities Attribute. It
1693is an optional transitive attribute. BGP Extended Communities Attribute can
1694carry multiple Extended Community value. Each Extended Community value is
1695eight octet length.
42fc5d26 1696
c1a54c05
QY
1697BGP Extended Communities Attribute provides an extended range compared with BGP
1698Communities Attribute. Adding to that there is a type field in each value to
1699provides community space structure.
42fc5d26 1700
c1a54c05
QY
1701There are two format to define Extended Community value. One is AS based format
1702the other is IP address based format.
42fc5d26 1703
8fcedbd2
QY
1704``AS:VAL``
1705 This is a format to define AS based Extended Community value. ``AS`` part
1706 is 2 octets Global Administrator subfield in Extended Community value.
1707 ``VAL`` part is 4 octets Local Administrator subfield. ``7675:100``
1708 represents AS 7675 policy value 100.
42fc5d26 1709
8fcedbd2 1710``IP-Address:VAL``
c1a54c05 1711 This is a format to define IP address based Extended Community value.
8fcedbd2
QY
1712 ``IP-Address`` part is 4 octets Global Administrator subfield. ``VAL`` part
1713 is 2 octets Local Administrator subfield.
42fc5d26 1714
0efdf0fe 1715.. _bgp-extended-community-lists:
42fc5d26 1716
8fcedbd2
QY
1717Extended Community Lists
1718^^^^^^^^^^^^^^^^^^^^^^^^
42fc5d26 1719
a64e0ee5
DA
1720.. index:: bgp extcommunity-list standard NAME permit|deny EXTCOMMUNITY
1721.. clicmd:: bgp extcommunity-list standard NAME permit|deny EXTCOMMUNITY
42fc5d26 1722
4da7fda3
QY
1723 This command defines a new standard extcommunity-list. `extcommunity` is
1724 extended communities value. The `extcommunity` is compiled into extended
1725 community structure. We can define multiple extcommunity-list under same
1726 name. In that case match will happen user defined order. Once the
1727 extcommunity-list matches to extended communities attribute in BGP updates
1728 it return permit or deny based upon the extcommunity-list definition. When
1729 there is no matched entry, deny will be returned. When `extcommunity` is
1730 empty it matches to any routes.
42fc5d26 1731
a64e0ee5
DA
1732.. index:: bgp extcommunity-list expanded NAME permit|deny LINE
1733.. clicmd:: bgp extcommunity-list expanded NAME permit|deny LINE
42fc5d26 1734
4da7fda3
QY
1735 This command defines a new expanded extcommunity-list. `line` is a string
1736 expression of extended communities attribute. `line` can be a regular
1737 expression (:ref:`bgp-regular-expressions`) to match an extended communities
1738 attribute in BGP updates.
42fc5d26 1739
a64e0ee5
DA
1740.. index:: no bgp extcommunity-list NAME
1741.. clicmd:: no bgp extcommunity-list NAME
42fc5d26 1742
a64e0ee5
DA
1743.. index:: no bgp extcommunity-list standard NAME
1744.. clicmd:: no bgp extcommunity-list standard NAME
42fc5d26 1745
a64e0ee5
DA
1746.. index:: no bgp extcommunity-list expanded NAME
1747.. clicmd:: no bgp extcommunity-list expanded NAME
42fc5d26 1748
4da7fda3
QY
1749 These commands delete extended community lists specified by `name`. All of
1750 extended community lists shares a single name space. So extended community
d1e7591e 1751 lists can be removed simply specifying the name.
42fc5d26 1752
a64e0ee5
DA
1753.. index:: show bgp extcommunity-list
1754.. clicmd:: show bgp extcommunity-list
42fc5d26 1755
a64e0ee5
DA
1756.. index:: show bgp extcommunity-list NAME
1757.. clicmd:: show bgp extcommunity-list NAME
c1a54c05 1758
4da7fda3 1759 This command displays current extcommunity-list information. When `name` is
9eb95b3b 1760 specified the community list's information is shown.::
42fc5d26 1761
a64e0ee5 1762 # show bgp extcommunity-list
c3c5a71f 1763
42fc5d26 1764
0efdf0fe 1765.. _bgp-extended-communities-in-route-map:
42fc5d26
QY
1766
1767BGP Extended Communities in Route Map
8fcedbd2 1768"""""""""""""""""""""""""""""""""""""
42fc5d26 1769
c3c5a71f 1770.. index:: match extcommunity WORD
29adcd50 1771.. clicmd:: match extcommunity WORD
42fc5d26 1772
c1a54c05 1773.. index:: set extcommunity rt EXTCOMMUNITY
29adcd50 1774.. clicmd:: set extcommunity rt EXTCOMMUNITY
42fc5d26 1775
c1a54c05 1776 This command set Route Target value.
42fc5d26 1777
c1a54c05 1778.. index:: set extcommunity soo EXTCOMMUNITY
29adcd50 1779.. clicmd:: set extcommunity soo EXTCOMMUNITY
c1a54c05
QY
1780
1781 This command set Site of Origin value.
42fc5d26 1782
47f47873
PG
1783
1784Note that the extended expanded community is only used for `match` rule, not for
1785`set` actions.
1786
0efdf0fe 1787.. _bgp-large-communities-attribute:
42fc5d26 1788
8fcedbd2
QY
1789Large Communities Attribute
1790^^^^^^^^^^^^^^^^^^^^^^^^^^^
42fc5d26
QY
1791
1792The BGP Large Communities attribute was introduced in Feb 2017 with
c1a54c05 1793:rfc:`8092`.
42fc5d26 1794
8fcedbd2
QY
1795The BGP Large Communities Attribute is similar to the BGP Communities Attribute
1796except that it has 3 components instead of two and each of which are 4 octets
1797in length. Large Communities bring additional functionality and convenience
1798over traditional communities, specifically the fact that the ``GLOBAL`` part
1799below is now 4 octets wide allowing seamless use in networks using 4-byte ASNs.
1800
1801``GLOBAL:LOCAL1:LOCAL2``
1802 This is the format to define Large Community values. Referencing :rfc:`8195`
1803 the values are commonly referred to as follows:
1804
1805 - The ``GLOBAL`` part is a 4 octet Global Administrator field, commonly used
1806 as the operators AS number.
1807 - The ``LOCAL1`` part is a 4 octet Local Data Part 1 subfield referred to as
1808 a function.
1809 - The ``LOCAL2`` part is a 4 octet Local Data Part 2 field and referred to
1810 as the parameter subfield.
1811
1812 As an example, ``65551:1:10`` represents AS 65551 function 1 and parameter
1813 10. The referenced RFC above gives some guidelines on recommended usage.
42fc5d26 1814
0efdf0fe 1815.. _bgp-large-community-lists:
42fc5d26 1816
8fcedbd2
QY
1817Large Community Lists
1818"""""""""""""""""""""
42fc5d26
QY
1819
1820Two types of large community lists are supported, namely `standard` and
1821`expanded`.
1822
a64e0ee5
DA
1823.. index:: bgp large-community-list standard NAME permit|deny LARGE-COMMUNITY
1824.. clicmd:: bgp large-community-list standard NAME permit|deny LARGE-COMMUNITY
42fc5d26 1825
4da7fda3
QY
1826 This command defines a new standard large-community-list. `large-community`
1827 is the Large Community value. We can add multiple large communities under
1828 same name. In that case the match will happen in the user defined order.
1829 Once the large-community-list matches the Large Communities attribute in BGP
1830 updates it will return permit or deny based upon the large-community-list
1831 definition. When there is no matched entry, a deny will be returned. When
1832 `large-community` is empty it matches any routes.
42fc5d26 1833
a64e0ee5
DA
1834.. index:: bgp large-community-list expanded NAME permit|deny LINE
1835.. clicmd:: bgp large-community-list expanded NAME permit|deny LINE
42fc5d26 1836
4da7fda3
QY
1837 This command defines a new expanded large-community-list. Where `line` is a
1838 string matching expression, it will be compared to the entire Large
1839 Communities attribute as a string, with each large-community in order from
1840 lowest to highest. `line` can also be a regular expression which matches
1841 this Large Community attribute.
42fc5d26 1842
a64e0ee5
DA
1843.. index:: no bgp large-community-list NAME
1844.. clicmd:: no bgp large-community-list NAME
42fc5d26 1845
a64e0ee5
DA
1846.. index:: no bgp large-community-list standard NAME
1847.. clicmd:: no bgp large-community-list standard NAME
42fc5d26 1848
a64e0ee5
DA
1849.. index:: no bgp large-community-list expanded NAME
1850.. clicmd:: no bgp large-community-list expanded NAME
42fc5d26 1851
4da7fda3
QY
1852 These commands delete Large Community lists specified by `name`. All Large
1853 Community lists share a single namespace. This means Large Community lists
1854 can be removed by simply specifying the name.
42fc5d26 1855
a64e0ee5
DA
1856.. index:: show bgp large-community-list
1857.. clicmd:: show bgp large-community-list
42fc5d26 1858
a64e0ee5
DA
1859.. index:: show bgp large-community-list NAME
1860.. clicmd:: show bgp large-community-list NAME
42fc5d26 1861
c1a54c05
QY
1862 This command display current large-community-list information. When
1863 `name` is specified the community list information is shown.
42fc5d26 1864
c1a54c05 1865.. index:: show ip bgp large-community-info
29adcd50 1866.. clicmd:: show ip bgp large-community-info
c1a54c05
QY
1867
1868 This command displays the current large communities in use.
42fc5d26 1869
0efdf0fe 1870.. _bgp-large-communities-in-route-map:
42fc5d26 1871
8fcedbd2
QY
1872Large Communities in Route Map
1873""""""""""""""""""""""""""""""
42fc5d26 1874
03ff9a14 1875.. index:: match large-community LINE [exact-match]
1876.. clicmd:: match large-community LINE [exact-match]
42fc5d26 1877
4da7fda3
QY
1878 Where `line` can be a simple string to match, or a regular expression. It
1879 is very important to note that this match occurs on the entire
c1a54c05 1880 large-community string as a whole, where each large-community is ordered
03ff9a14 1881 from lowest to highest. When `exact-match` keyword is specified, match
1882 happen only when BGP updates have completely same large communities value
1883 specified in the large community list.
42fc5d26 1884
c1a54c05 1885.. index:: set large-community LARGE-COMMUNITY
29adcd50 1886.. clicmd:: set large-community LARGE-COMMUNITY
42fc5d26 1887
c1a54c05 1888.. index:: set large-community LARGE-COMMUNITY LARGE-COMMUNITY
29adcd50 1889.. clicmd:: set large-community LARGE-COMMUNITY LARGE-COMMUNITY
42fc5d26 1890
c1a54c05 1891.. index:: set large-community LARGE-COMMUNITY additive
29adcd50 1892.. clicmd:: set large-community LARGE-COMMUNITY additive
c1a54c05
QY
1893
1894 These commands are used for setting large-community values. The first
1895 command will overwrite any large-communities currently present.
1896 The second specifies two large-communities, which overwrites the current
1897 large-community list. The third will add a large-community value without
1898 overwriting other values. Multiple large-community values can be specified.
42fc5d26 1899
47f47873
PG
1900Note that the large expanded community is only used for `match` rule, not for
1901`set` actions.
b572f826 1902
c8a5e5e1 1903.. _bgp-l3vpn-vrfs:
b572f826 1904
c8a5e5e1
QY
1905L3VPN VRFs
1906----------
b572f826 1907
c8a5e5e1
QY
1908*bgpd* supports :abbr:`L3VPN (Layer 3 Virtual Private Networks)` :abbr:`VRFs
1909(Virtual Routing and Forwarding)` for IPv4 :rfc:`4364` and IPv6 :rfc:`4659`.
1910L3VPN routes, and their associated VRF MPLS labels, can be distributed to VPN
1911SAFI neighbors in the *default*, i.e., non VRF, BGP instance. VRF MPLS labels
1912are reached using *core* MPLS labels which are distributed using LDP or BGP
1913labeled unicast. *bgpd* also supports inter-VRF route leaking.
b572f826 1914
b572f826 1915
c8a5e5e1 1916.. _bgp-vrf-route-leaking:
8fcedbd2
QY
1917
1918VRF Route Leaking
c8a5e5e1 1919-----------------
8fcedbd2
QY
1920
1921BGP routes may be leaked (i.e. copied) between a unicast VRF RIB and the VPN
f90115c5
LB
1922SAFI RIB of the default VRF for use in MPLS-based L3VPNs. Unicast routes may
1923also be leaked between any VRFs (including the unicast RIB of the default BGP
1924instanced). A shortcut syntax is also available for specifying leaking from one
1925VRF to another VRF using the default instance's VPN RIB as the intemediary. A
1926common application of the VRF-VRF feature is to connect a customer's private
8fcedbd2
QY
1927routing domain to a provider's VPN service. Leaking is configured from the
1928point of view of an individual VRF: ``import`` refers to routes leaked from VPN
1929to a unicast VRF, whereas ``export`` refers to routes leaked from a unicast VRF
1930to VPN.
1931
1932Required parameters
c8a5e5e1 1933^^^^^^^^^^^^^^^^^^^
b572f826 1934
4da7fda3
QY
1935Routes exported from a unicast VRF to the VPN RIB must be augmented by two
1936parameters:
1937
1938- an :abbr:`RD (Route Distinguisher)`
1939- an :abbr:`RTLIST (Route-target List)`
1940
1941Configuration for these exported routes must, at a minimum, specify these two
1942parameters.
1943
1944Routes imported from the VPN RIB to a unicast VRF are selected according to
1945their RTLISTs. Routes whose RTLIST contains at least one route-target in
1946common with the configured import RTLIST are leaked. Configuration for these
1947imported routes must specify an RTLIST to be matched.
1948
1949The RD, which carries no semantic value, is intended to make the route unique
1950in the VPN RIB among all routes of its prefix that originate from all the
1951customers and sites that are attached to the provider's VPN service.
1952Accordingly, each site of each customer is typically assigned an RD that is
1953unique across the entire provider network.
1954
1955The RTLIST is a set of route-target extended community values whose purpose is
1956to specify route-leaking policy. Typically, a customer is assigned a single
1957route-target value for import and export to be used at all customer sites. This
1958configuration specifies a simple topology wherein a customer has a single
1959routing domain which is shared across all its sites. More complex routing
1960topologies are possible through use of additional route-targets to augment the
1961leaking of sets of routes in various ways.
b572f826 1962
e967a1d0
DS
1963When using the shortcut syntax for vrf-to-vrf leaking, the RD and RT are
1964auto-derived.
fb3d9f3e 1965
8fcedbd2 1966General configuration
c8a5e5e1 1967^^^^^^^^^^^^^^^^^^^^^
b572f826 1968
f90115c5 1969Configuration of route leaking between a unicast VRF RIB and the VPN SAFI RIB
4da7fda3
QY
1970of the default VRF is accomplished via commands in the context of a VRF
1971address-family:
b572f826
PZ
1972
1973.. index:: rd vpn export AS:NN|IP:nn
1974.. clicmd:: rd vpn export AS:NN|IP:nn
1975
4da7fda3
QY
1976 Specifies the route distinguisher to be added to a route exported from the
1977 current unicast VRF to VPN.
b572f826
PZ
1978
1979.. index:: no rd vpn export [AS:NN|IP:nn]
1980.. clicmd:: no rd vpn export [AS:NN|IP:nn]
1981
1982 Deletes any previously-configured export route distinguisher.
1983
1984.. index:: rt vpn import|export|both RTLIST...
1985.. clicmd:: rt vpn import|export|both RTLIST...
1986
4da7fda3
QY
1987 Specifies the route-target list to be attached to a route (export) or the
1988 route-target list to match against (import) when exporting/importing between
1989 the current unicast VRF and VPN.
b572f826 1990
4da7fda3
QY
1991 The RTLIST is a space-separated list of route-targets, which are BGP
1992 extended community values as described in
b572f826
PZ
1993 :ref:`bgp-extended-communities-attribute`.
1994
1995.. index:: no rt vpn import|export|both [RTLIST...]
1996.. clicmd:: no rt vpn import|export|both [RTLIST...]
1997
1998 Deletes any previously-configured import or export route-target list.
1999
e70e9f8e
PZ
2000.. index:: label vpn export (0..1048575)|auto
2001.. clicmd:: label vpn export (0..1048575)|auto
b572f826 2002
8a2124f7 2003 Enables an MPLS label to be attached to a route exported from the current
2004 unicast VRF to VPN. If the value specified is ``auto``, the label value is
2005 automatically assigned from a pool maintained by the Zebra daemon. If Zebra
2006 is not running, or if this command is not configured, automatic label
2007 assignment will not complete, which will block corresponding route export.
b572f826 2008
e70e9f8e
PZ
2009.. index:: no label vpn export [(0..1048575)|auto]
2010.. clicmd:: no label vpn export [(0..1048575)|auto]
b572f826
PZ
2011
2012 Deletes any previously-configured export label.
2013
2014.. index:: nexthop vpn export A.B.C.D|X:X::X:X
2015.. clicmd:: nexthop vpn export A.B.C.D|X:X::X:X
2016
4da7fda3
QY
2017 Specifies an optional nexthop value to be assigned to a route exported from
2018 the current unicast VRF to VPN. If left unspecified, the nexthop will be set
2019 to 0.0.0.0 or 0:0::0:0 (self).
b572f826
PZ
2020
2021.. index:: no nexthop vpn export [A.B.C.D|X:X::X:X]
2022.. clicmd:: no nexthop vpn export [A.B.C.D|X:X::X:X]
2023
2024 Deletes any previously-configured export nexthop.
2025
2026.. index:: route-map vpn import|export MAP
2027.. clicmd:: route-map vpn import|export MAP
2028
4da7fda3 2029 Specifies an optional route-map to be applied to routes imported or exported
d1e7591e 2030 between the current unicast VRF and VPN.
b572f826
PZ
2031
2032.. index:: no route-map vpn import|export [MAP]
2033.. clicmd:: no route-map vpn import|export [MAP]
2034
2035 Deletes any previously-configured import or export route-map.
2036
2037.. index:: import|export vpn
2038.. clicmd:: import|export vpn
2039
d1e7591e 2040 Enables import or export of routes between the current unicast VRF and VPN.
b572f826
PZ
2041
2042.. index:: no import|export vpn
2043.. clicmd:: no import|export vpn
2044
d1e7591e 2045 Disables import or export of routes between the current unicast VRF and VPN.
b572f826 2046
fb3d9f3e
DS
2047.. index:: import vrf VRFNAME
2048.. clicmd:: import vrf VRFNAME
2049
e967a1d0
DS
2050 Shortcut syntax for specifying automatic leaking from vrf VRFNAME to
2051 the current VRF using the VPN RIB as intermediary. The RD and RT
2052 are auto derived and should not be specified explicitly for either the
2053 source or destination VRF's.
2054
2055 This shortcut syntax mode is not compatible with the explicit
2056 `import vpn` and `export vpn` statements for the two VRF's involved.
2057 The CLI will disallow attempts to configure incompatible leaking
2058 modes.
fb3d9f3e
DS
2059
2060.. index:: no import vrf VRFNAME
2061.. clicmd:: no import vrf VRFNAME
2062
e967a1d0
DS
2063 Disables automatic leaking from vrf VRFNAME to the current VRF using
2064 the VPN RIB as intermediary.
b572f826 2065
42fc5d26 2066
b6c34e85
CS
2067.. _bgp-evpn:
2068
2069Ethernet Virtual Network - EVPN
2070-------------------------------
2071
2072.. _bgp-evpn-advertise-pip:
2073
2074EVPN advertise-PIP
2075^^^^^^^^^^^^^^^^^^
2076
2077In a EVPN symmetric routing MLAG deployment, all EVPN routes advertised
2078with anycast-IP as next-hop IP and anycast MAC as the Router MAC (RMAC - in
2079BGP EVPN Extended-Community).
2080EVPN picks up the next-hop IP from the VxLAN interface's local tunnel IP and
2081the RMAC is obtained from the MAC of the L3VNI's SVI interface.
2082Note: Next-hop IP is used for EVPN routes whether symmetric routing is
2083deployed or not but the RMAC is only relevant for symmetric routing scenario.
2084
2085Current behavior is not ideal for Prefix (type-5) and self (type-2)
2086routes. This is because the traffic from remote VTEPs routed sub optimally
2087if they land on the system where the route does not belong.
2088
2089The advertise-pip feature advertises Prefix (type-5) and self (type-2)
2090routes with system's individual (primary) IP as the next-hop and individual
2091(system) MAC as Router-MAC (RMAC), while leaving the behavior unchanged for
2092other EVPN routes.
2093
2094To support this feature there needs to have ability to co-exist a
2095(system-MAC, system-IP) pair with a (anycast-MAC, anycast-IP) pair with the
2096ability to terminate VxLAN-encapsulated packets received for either pair on
2097the same L3VNI (i.e associated VLAN). This capability is need per tenant
2098VRF instance.
2099
2100To derive the system-MAC and the anycast MAC, there needs to have a
2101separate/additional MAC-VLAN interface corresponding to L3VNI’s SVI.
2102The SVI interface’s MAC address can be interpreted as system-MAC
2103and MAC-VLAN interface's MAC as anycast MAC.
2104
2105To derive system-IP and anycast-IP, the default BGP instance's router-id is used
2106as system-IP and the VxLAN interface’s local tunnel IP as the anycast-IP.
2107
2108User has an option to configure the system-IP and/or system-MAC value if the
2109auto derived value is not preferred.
2110
2111Note: By default, advertise-pip feature is enabled and user has an option to
2112disable the feature via configuration CLI. Once the feature is disable under
2113bgp vrf instance or MAC-VLAN interface is not configured, all the routes follow
2114the same behavior of using same next-hop and RMAC values.
2115
2116.. index:: [no] advertise-pip [ip <addr> [mac <addr>]]
2117.. clicmd:: [no] advertise-pip [ip <addr> [mac <addr>]]
2118
2119Enables or disables advertise-pip feature, specifiy system-IP and/or system-MAC
2120parameters.
2121
8fcedbd2 2122.. _bgp-cisco-compatibility:
42fc5d26 2123
8fcedbd2
QY
2124Cisco Compatibility
2125-------------------
42fc5d26 2126
8fcedbd2
QY
2127FRR has commands that change some configuration syntax and default behavior to
2128behave more closely to Cisco conventions. These are deprecated and will be
2129removed in a future version of FRR.
42fc5d26 2130
8fcedbd2
QY
2131.. deprecated:: 5.0
2132 Please transition to using the FRR specific syntax for your configuration.
42fc5d26 2133
8fcedbd2
QY
2134.. index:: bgp config-type cisco
2135.. clicmd:: bgp config-type cisco
42fc5d26 2136
8fcedbd2 2137 Cisco compatible BGP configuration output.
42fc5d26 2138
8fcedbd2 2139 When this configuration line is specified:
c1a54c05 2140
8fcedbd2
QY
2141 - ``no synchronization`` is displayed. This command does nothing and is for
2142 display purposes only.
2143 - ``no auto-summary`` is displayed.
2144 - The ``network`` and ``aggregate-address`` arguments are displayed as:
42fc5d26 2145
8fcedbd2 2146 ::
42fc5d26 2147
8fcedbd2 2148 A.B.C.D M.M.M.M
42fc5d26 2149
8fcedbd2
QY
2150 FRR: network 10.0.0.0/8
2151 Cisco: network 10.0.0.0
42fc5d26 2152
8fcedbd2
QY
2153 FRR: aggregate-address 192.168.0.0/24
2154 Cisco: aggregate-address 192.168.0.0 255.255.255.0
42fc5d26 2155
8fcedbd2
QY
2156 Community attribute handling is also different. If no configuration is
2157 specified community attribute and extended community attribute are sent to
2158 the neighbor. If a user manually disables the feature, the community
2159 attribute is not sent to the neighbor. When ``bgp config-type cisco`` is
2160 specified, the community attribute is not sent to the neighbor by default.
2161 To send the community attribute user has to specify
2162 :clicmd:`neighbor A.B.C.D send-community` like so:
42fc5d26 2163
8fcedbd2 2164 .. code-block:: frr
42fc5d26 2165
8fcedbd2
QY
2166 !
2167 router bgp 1
2168 neighbor 10.0.0.1 remote-as 1
2169 address-family ipv4 unicast
2170 no neighbor 10.0.0.1 send-community
2171 exit-address-family
2172 !
2173 router bgp 1
2174 neighbor 10.0.0.1 remote-as 1
2175 address-family ipv4 unicast
2176 neighbor 10.0.0.1 send-community
2177 exit-address-family
2178 !
42fc5d26 2179
8fcedbd2
QY
2180.. deprecated:: 5.0
2181 Please transition to using the FRR specific syntax for your configuration.
2182
2183.. index:: bgp config-type zebra
2184.. clicmd:: bgp config-type zebra
2185
2186 FRR style BGP configuration. This is the default.
2187
2188.. _bgp-debugging:
2189
2190Debugging
2191---------
42fc5d26 2192
c1a54c05 2193.. index:: show debug
29adcd50 2194.. clicmd:: show debug
42fc5d26 2195
8fcedbd2 2196 Show all enabled debugs.
42fc5d26 2197
53b758f3
PG
2198.. index:: [no] debug bgp neighbor-events
2199.. clicmd:: [no] debug bgp neighbor-events
42fc5d26 2200
8fcedbd2
QY
2201 Enable or disable debugging for neighbor events. This provides general
2202 information on BGP events such as peer connection / disconnection, session
2203 establishment / teardown, and capability negotiation.
42fc5d26 2204
53b758f3
PG
2205.. index:: [no] debug bgp updates
2206.. clicmd:: [no] debug bgp updates
42fc5d26 2207
8fcedbd2
QY
2208 Enable or disable debugging for BGP updates. This provides information on
2209 BGP UPDATE messages transmitted and received between local and remote
2210 instances.
42fc5d26 2211
53b758f3
PG
2212.. index:: [no] debug bgp keepalives
2213.. clicmd:: [no] debug bgp keepalives
42fc5d26 2214
8fcedbd2
QY
2215 Enable or disable debugging for BGP keepalives. This provides information on
2216 BGP KEEPALIVE messages transmitted and received between local and remote
2217 instances.
c1a54c05 2218
8fcedbd2
QY
2219.. index:: [no] debug bgp bestpath <A.B.C.D/M|X:X::X:X/M>
2220.. clicmd:: [no] debug bgp bestpath <A.B.C.D/M|X:X::X:X/M>
42fc5d26 2221
8fcedbd2 2222 Enable or disable debugging for bestpath selection on the specified prefix.
42fc5d26 2223
8fcedbd2
QY
2224.. index:: [no] debug bgp nht
2225.. clicmd:: [no] debug bgp nht
4da7fda3 2226
8fcedbd2 2227 Enable or disable debugging of BGP nexthop tracking.
4da7fda3 2228
8fcedbd2
QY
2229.. index:: [no] debug bgp update-groups
2230.. clicmd:: [no] debug bgp update-groups
4b44467c 2231
8fcedbd2
QY
2232 Enable or disable debugging of dynamic update groups. This provides general
2233 information on group creation, deletion, join and prune events.
4b44467c 2234
8fcedbd2
QY
2235.. index:: [no] debug bgp zebra
2236.. clicmd:: [no] debug bgp zebra
42fc5d26 2237
8fcedbd2 2238 Enable or disable debugging of communications between *bgpd* and *zebra*.
c3c5a71f 2239
8fcedbd2
QY
2240Dumping Messages and Routing Tables
2241^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
42fc5d26 2242
8fcedbd2
QY
2243.. index:: dump bgp all PATH [INTERVAL]
2244.. clicmd:: dump bgp all PATH [INTERVAL]
42fc5d26 2245
8fcedbd2
QY
2246.. index:: dump bgp all-et PATH [INTERVAL]
2247.. clicmd:: dump bgp all-et PATH [INTERVAL]
c3c5a71f 2248
8fcedbd2
QY
2249.. index:: no dump bgp all [PATH] [INTERVAL]
2250.. clicmd:: no dump bgp all [PATH] [INTERVAL]
42fc5d26 2251
8fcedbd2
QY
2252 Dump all BGP packet and events to `path` file.
2253 If `interval` is set, a new file will be created for echo `interval` of
2254 seconds. The path `path` can be set with date and time formatting
2255 (strftime). The type ‘all-et’ enables support for Extended Timestamp Header
2256 (:ref:`packet-binary-dump-format`).
c3c5a71f 2257
8fcedbd2
QY
2258.. index:: dump bgp updates PATH [INTERVAL]
2259.. clicmd:: dump bgp updates PATH [INTERVAL]
42fc5d26 2260
8fcedbd2
QY
2261.. index:: dump bgp updates-et PATH [INTERVAL]
2262.. clicmd:: dump bgp updates-et PATH [INTERVAL]
42fc5d26 2263
8fcedbd2
QY
2264.. index:: no dump bgp updates [PATH] [INTERVAL]
2265.. clicmd:: no dump bgp updates [PATH] [INTERVAL]
42fc5d26 2266
8fcedbd2
QY
2267 Dump only BGP updates messages to `path` file.
2268 If `interval` is set, a new file will be created for echo `interval` of
2269 seconds. The path `path` can be set with date and time formatting
2270 (strftime). The type ‘updates-et’ enables support for Extended Timestamp
2271 Header (:ref:`packet-binary-dump-format`).
42fc5d26 2272
8fcedbd2
QY
2273.. index:: dump bgp routes-mrt PATH
2274.. clicmd:: dump bgp routes-mrt PATH
c3c5a71f 2275
8fcedbd2
QY
2276.. index:: dump bgp routes-mrt PATH INTERVAL
2277.. clicmd:: dump bgp routes-mrt PATH INTERVAL
42fc5d26 2278
8fcedbd2
QY
2279.. index:: no dump bgp route-mrt [PATH] [INTERVAL]
2280.. clicmd:: no dump bgp route-mrt [PATH] [INTERVAL]
42fc5d26 2281
8fcedbd2
QY
2282 Dump whole BGP routing table to `path`. This is heavy process. The path
2283 `path` can be set with date and time formatting (strftime). If `interval` is
2284 set, a new file will be created for echo `interval` of seconds.
42fc5d26 2285
8fcedbd2 2286 Note: the interval variable can also be set using hours and minutes: 04h20m00.
42fc5d26 2287
c3c5a71f 2288
8fcedbd2 2289.. _bgp-other-commands:
42fc5d26 2290
8fcedbd2
QY
2291Other BGP Commands
2292------------------
42fc5d26 2293
e312b6c6
QY
2294The following are available in the top level *enable* mode:
2295
dc912615
DS
2296.. index:: clear bgp \*
2297.. clicmd:: clear bgp \*
2298
2299 Clear all peers.
2300
8fcedbd2
QY
2301.. index:: clear bgp ipv4|ipv6 \*
2302.. clicmd:: clear bgp ipv4|ipv6 \*
42fc5d26 2303
dc912615
DS
2304 Clear all peers with this address-family activated.
2305
2306.. index:: clear bgp ipv4|ipv6 unicast \*
2307.. clicmd:: clear bgp ipv4|ipv6 unicast \*
2308
2309 Clear all peers with this address-family and sub-address-family activated.
42fc5d26 2310
8fcedbd2
QY
2311.. index:: clear bgp ipv4|ipv6 PEER
2312.. clicmd:: clear bgp ipv4|ipv6 PEER
42fc5d26 2313
dc912615
DS
2314 Clear peers with address of X.X.X.X and this address-family activated.
2315
2316.. index:: clear bgp ipv4|ipv6 unicast PEER
2317.. clicmd:: clear bgp ipv4|ipv6 unicast PEER
2318
2319 Clear peer with address of X.X.X.X and this address-family and sub-address-family activated.
2320
2321.. index:: clear bgp ipv4|ipv6 PEER soft|in|out
2322.. clicmd:: clear bgp ipv4|ipv6 PEER soft|in|out
2323
2324 Clear peer using soft reconfiguration in this address-family.
42fc5d26 2325
dc912615
DS
2326.. index:: clear bgp ipv4|ipv6 unicast PEER soft|in|out
2327.. clicmd:: clear bgp ipv4|ipv6 unicast PEER soft|in|out
42fc5d26 2328
dc912615 2329 Clear peer using soft reconfiguration in this address-family and sub-address-family.
42fc5d26 2330
e312b6c6
QY
2331The following are available in the ``router bgp`` mode:
2332
2333.. index:: write-quanta (1-64)
2334.. clicmd:: write-quanta (1-64)
2335
2336 BGP message Tx I/O is vectored. This means that multiple packets are written
2337 to the peer socket at the same time each I/O cycle, in order to minimize
2338 system call overhead. This value controls how many are written at a time.
2339 Under certain load conditions, reducing this value could make peer traffic
2340 less 'bursty'. In practice, leave this settings on the default (64) unless
2341 you truly know what you are doing.
2342
2343.. index:: read-quanta (1-10)
dad83b67 2344.. clicmd:: read-quanta (1-10)
e312b6c6
QY
2345
2346 Unlike Tx, BGP Rx traffic is not vectored. Packets are read off the wire one
2347 at a time in a loop. This setting controls how many iterations the loop runs
2348 for. As with write-quanta, it is best to leave this setting on the default.
42fc5d26 2349
8fcedbd2 2350.. _bgp-displaying-bgp-information:
42fc5d26 2351
8fcedbd2
QY
2352Displaying BGP Information
2353==========================
42fc5d26 2354
e6f59415
PG
2355The following four commands display the IPv6 and IPv4 routing tables, depending
2356on whether or not the ``ip`` keyword is used.
2357Actually, :clicmd:`show ip bgp` command was used on older `Quagga` routing
2358daemon project, while :clicmd:`show bgp` command is the new format. The choice
2359has been done to keep old format with IPv4 routing table, while new format
2360displays IPv6 routing table.
2361
8fcedbd2
QY
2362.. index:: show ip bgp
2363.. clicmd:: show ip bgp
42fc5d26 2364
8fcedbd2
QY
2365.. index:: show ip bgp A.B.C.D
2366.. clicmd:: show ip bgp A.B.C.D
c1a54c05 2367
e6f59415
PG
2368.. index:: show bgp
2369.. clicmd:: show bgp
2370
2371.. index:: show bgp X:X::X:X
2372.. clicmd:: show bgp X:X::X:X
42fc5d26 2373
8fcedbd2 2374 These commands display BGP routes. When no route is specified, the default
e6f59415 2375 is to display all BGP routes.
42fc5d26 2376
8fcedbd2 2377 ::
c1a54c05 2378
8fcedbd2
QY
2379 BGP table version is 0, local router ID is 10.1.1.1
2380 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
2381 Origin codes: i - IGP, e - EGP, ? - incomplete
42fc5d26 2382
8fcedbd2
QY
2383 Network Next Hop Metric LocPrf Weight Path
2384 \*> 1.1.1.1/32 0.0.0.0 0 32768 i
42fc5d26 2385
8fcedbd2 2386 Total number of prefixes 1
4da7fda3 2387
e6f59415
PG
2388Some other commands provide additional options for filtering the output.
2389
2390.. index:: show [ip] bgp regexp LINE
2391.. clicmd:: show [ip] bgp regexp LINE
42fc5d26 2392
8fcedbd2
QY
2393 This command displays BGP routes using AS path regular expression
2394 (:ref:`bgp-regular-expressions`).
42fc5d26 2395
e6f59415
PG
2396.. index:: show [ip] bgp summary
2397.. clicmd:: show [ip] bgp summary
42fc5d26 2398
8fcedbd2 2399 Show a bgp peer summary for the specified address family.
42fc5d26 2400
e6f59415
PG
2401The old command structure :clicmd:`show ip bgp` may be removed in the future
2402and should no longer be used. In order to reach the other BGP routing tables
2403other than the IPv6 routing table given by :clicmd:`show bgp`, the new command
2404structure is extended with :clicmd:`show bgp [afi] [safi]`.
2405
2406.. index:: show bgp [afi] [safi]
2407.. clicmd:: show bgp [afi] [safi]
2408
2409.. index:: show bgp <ipv4|ipv6> <unicast|multicast|vpn|labeled-unicast>
2410.. clicmd:: show bgp <ipv4|ipv6> <unicast|multicast|vpn|labeled-unicast>
2411
2412 These commands display BGP routes for the specific routing table indicated by
2413 the selected afi and the selected safi. If no afi and no safi value is given,
2414 the command falls back to the default IPv6 routing table
2415
2416.. index:: show bgp [afi] [safi] summary
2417.. clicmd:: show bgp [afi] [safi] summary
2418
2419 Show a bgp peer summary for the specified address family, and subsequent
2420 address-family.
2421
3577f1c5
DD
2422.. index:: show bgp [afi] [safi] summary failed [json]
2423.. clicmd:: show bgp [afi] [safi] summary failed [json]
2424
2425 Show a bgp peer summary for peers that are not succesfully exchanging routes
2426 for the specified address family, and subsequent address-family.
2427
e6f59415
PG
2428.. index:: show bgp [afi] [safi] neighbor [PEER]
2429.. clicmd:: show bgp [afi] [safi] neighbor [PEER]
9eb95b3b 2430
e6f59415
PG
2431 This command shows information on a specific BGP peer of the relevant
2432 afi and safi selected.
c1a54c05 2433
e6f59415
PG
2434.. index:: show bgp [afi] [safi] dampening dampened-paths
2435.. clicmd:: show bgp [afi] [safi] dampening dampened-paths
42fc5d26 2436
e6f59415
PG
2437 Display paths suppressed due to dampening of the selected afi and safi
2438 selected.
42fc5d26 2439
e6f59415
PG
2440.. index:: show bgp [afi] [safi] dampening flap-statistics
2441.. clicmd:: show bgp [afi] [safi] dampening flap-statistics
c1a54c05 2442
e6f59415 2443 Display flap statistics of routes of the selected afi and safi selected.
42fc5d26 2444
8fcedbd2 2445.. _bgp-display-routes-by-community:
42fc5d26 2446
8fcedbd2
QY
2447Displaying Routes by Community Attribute
2448----------------------------------------
42fc5d26 2449
8fcedbd2
QY
2450The following commands allow displaying routes based on their community
2451attribute.
42fc5d26 2452
8fcedbd2
QY
2453.. index:: show [ip] bgp <ipv4|ipv6> community
2454.. clicmd:: show [ip] bgp <ipv4|ipv6> community
42fc5d26 2455
8fcedbd2
QY
2456.. index:: show [ip] bgp <ipv4|ipv6> community COMMUNITY
2457.. clicmd:: show [ip] bgp <ipv4|ipv6> community COMMUNITY
42fc5d26 2458
8fcedbd2
QY
2459.. index:: show [ip] bgp <ipv4|ipv6> community COMMUNITY exact-match
2460.. clicmd:: show [ip] bgp <ipv4|ipv6> community COMMUNITY exact-match
76bd1499 2461
8fcedbd2
QY
2462 These commands display BGP routes which have the community attribute.
2463 attribute. When ``COMMUNITY`` is specified, BGP routes that match that
2464 community are displayed. When `exact-match` is specified, it display only
2465 routes that have an exact match.
c3c5a71f 2466
8fcedbd2
QY
2467.. index:: show [ip] bgp <ipv4|ipv6> community-list WORD
2468.. clicmd:: show [ip] bgp <ipv4|ipv6> community-list WORD
42fc5d26 2469
8fcedbd2
QY
2470.. index:: show [ip] bgp <ipv4|ipv6> community-list WORD exact-match
2471.. clicmd:: show [ip] bgp <ipv4|ipv6> community-list WORD exact-match
42fc5d26 2472
8fcedbd2
QY
2473 These commands display BGP routes for the address family specified that
2474 match the specified community list. When `exact-match` is specified, it
2475 displays only routes that have an exact match.
42fc5d26 2476
36a206db 2477.. _bgp-display-routes-by-lcommunity:
2478
2479Displaying Routes by Large Community Attribute
2480----------------------------------------------
2481
ac2201bb 2482The following commands allow displaying routes based on their
36a206db 2483large community attribute.
2484
2485.. index:: show [ip] bgp <ipv4|ipv6> large-community
2486.. clicmd:: show [ip] bgp <ipv4|ipv6> large-community
2487
2488.. index:: show [ip] bgp <ipv4|ipv6> large-community LARGE-COMMUNITY
2489.. clicmd:: show [ip] bgp <ipv4|ipv6> large-community LARGE-COMMUNITY
2490
2491.. index:: show [ip] bgp <ipv4|ipv6> large-community LARGE-COMMUNITY exact-match
2492.. clicmd:: show [ip] bgp <ipv4|ipv6> large-community LARGE-COMMUNITY exact-match
2493
2494.. index:: show [ip] bgp <ipv4|ipv6> large-community LARGE-COMMUNITY json
2495.. clicmd:: show [ip] bgp <ipv4|ipv6> large-community LARGE-COMMUNITY json
2496
2497 These commands display BGP routes which have the large community attribute.
2498 attribute. When ``LARGE-COMMUNITY`` is specified, BGP routes that match that
ac2201bb
DA
2499 large community are displayed. When `exact-match` is specified, it display
2500 only routes that have an exact match. When `json` is specified, it display
36a206db 2501 routes in json format.
2502
2503.. index:: show [ip] bgp <ipv4|ipv6> large-community-list WORD
2504.. clicmd:: show [ip] bgp <ipv4|ipv6> large-community-list WORD
2505
2506.. index:: show [ip] bgp <ipv4|ipv6> large-community-list WORD exact-match
2507.. clicmd:: show [ip] bgp <ipv4|ipv6> large-community-list WORD exact-match
2508
2509.. index:: show [ip] bgp <ipv4|ipv6> large-community-list WORD json
2510.. clicmd:: show [ip] bgp <ipv4|ipv6> large-community-list WORD json
2511
2512 These commands display BGP routes for the address family specified that
ac2201bb
DA
2513 match the specified large community list. When `exact-match` is specified,
2514 it displays only routes that have an exact match. When `json` is specified,
36a206db 2515 it display routes in json format.
2516
8fcedbd2 2517.. _bgp-display-routes-by-as-path:
42fc5d26 2518
36a206db 2519
8fcedbd2
QY
2520Displaying Routes by AS Path
2521----------------------------
42fc5d26 2522
8fcedbd2
QY
2523.. index:: show bgp ipv4|ipv6 regexp LINE
2524.. clicmd:: show bgp ipv4|ipv6 regexp LINE
76bd1499 2525
8fcedbd2
QY
2526 This commands displays BGP routes that matches a regular
2527 expression `line` (:ref:`bgp-regular-expressions`).
2528
e6f59415
PG
2529.. index:: show [ip] bgp ipv4 vpn
2530.. clicmd:: show [ip] bgp ipv4 vpn
8fcedbd2 2531
e6f59415
PG
2532.. index:: show [ip] bgp ipv6 vpn
2533.. clicmd:: show [ip] bgp ipv6 vpn
8fcedbd2
QY
2534
2535 Print active IPV4 or IPV6 routes advertised via the VPN SAFI.
2536
2537.. index:: show bgp ipv4 vpn summary
2538.. clicmd:: show bgp ipv4 vpn summary
2539
2540.. index:: show bgp ipv6 vpn summary
2541.. clicmd:: show bgp ipv6 vpn summary
2542
2543 Print a summary of neighbor connections for the specified AFI/SAFI combination.
2544
09d78f10
DS
2545Displaying Update Group Information
2546-----------------------------------
2547
2548..index:: show bgp update-groups SUBGROUP-ID [advertise-queue|advertised-routes|packet-queue]
2549..clicmd:: show bgp update-groups [advertise-queue|advertised-routes|packet-queue]
2550
2551 Display Information about each individual update-group being used.
2552 If SUBGROUP-ID is specified only display about that particular group. If
2553 advertise-queue is specified the list of routes that need to be sent
2554 to the peers in the update-group is displayed, advertised-routes means
a64e0ee5 2555 the list of routes we have sent to the peers in the update-group and
09d78f10
DS
2556 packet-queue specifies the list of packets in the queue to be sent.
2557
2558..index:: show bgp update-groups statistics
2559..clicmd:: show bgp update-groups statistics
2560
2561 Display Information about update-group events in FRR.
8fcedbd2
QY
2562
2563.. _bgp-route-reflector:
2564
2565Route Reflector
2566===============
2567
749afd7d
RF
2568BGP routers connected inside the same AS through BGP belong to an internal
2569BGP session, or IBGP. In order to prevent routing table loops, IBGP does not
2570advertise IBGP-learned routes to other routers in the same session. As such,
2571IBGP requires a full mesh of all peers. For large networks, this quickly becomes
2572unscalable. Introducing route reflectors removes the need for the full-mesh.
8fcedbd2 2573
749afd7d
RF
2574When route reflectors are configured, these will reflect the routes announced
2575by the peers configured as clients. A route reflector client is configured
2576with:
8fcedbd2
QY
2577
2578.. index:: neighbor PEER route-reflector-client
2579.. clicmd:: neighbor PEER route-reflector-client
2580
2581.. index:: no neighbor PEER route-reflector-client
2582.. clicmd:: no neighbor PEER route-reflector-client
c3c5a71f 2583
749afd7d
RF
2584To avoid single points of failure, multiple route reflectors can be configured.
2585
2586A cluster is a collection of route reflectors and their clients, and is used
2587by route reflectors to avoid looping.
2588
2589.. index:: bgp cluster-id A.B.C.D
2590.. clicmd:: bgp cluster-id A.B.C.D
42fc5d26 2591
0efdf0fe 2592.. _routing-policy:
42fc5d26 2593
8fcedbd2
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2594Routing Policy
2595==============
42fc5d26 2596
4da7fda3 2597You can set different routing policy for a peer. For example, you can set
9eb95b3b
QY
2598different filter for a peer.
2599
2600.. code-block:: frr
c1a54c05 2601
c1a54c05
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2602 !
2603 router bgp 1 view 1
2604 neighbor 10.0.0.1 remote-as 2
2605 address-family ipv4 unicast
2606 neighbor 10.0.0.1 distribute-list 1 in
2607 exit-address-family
2608 !
2609 router bgp 1 view 2
2610 neighbor 10.0.0.1 remote-as 2
2611 address-family ipv4 unicast
2612 neighbor 10.0.0.1 distribute-list 2 in
2613 exit-address-family
c3c5a71f 2614
4da7fda3
QY
2615This means BGP update from a peer 10.0.0.1 goes to both BGP view 1 and view 2.
2616When the update is inserted into view 1, distribute-list 1 is applied. On the
2617other hand, when the update is inserted into view 2, distribute-list 2 is
2618applied.
42fc5d26 2619
42fc5d26 2620
0efdf0fe 2621.. _bgp-regular-expressions:
42fc5d26
QY
2622
2623BGP Regular Expressions
2624=======================
2625
8fcedbd2
QY
2626BGP regular expressions are based on :t:`POSIX 1003.2` regular expressions. The
2627following description is just a quick subset of the POSIX regular expressions.
42fc5d26
QY
2628
2629
8fcedbd2 2630.\*
c1a54c05 2631 Matches any single character.
42fc5d26 2632
8fcedbd2 2633\*
c1a54c05 2634 Matches 0 or more occurrences of pattern.
42fc5d26 2635
8fcedbd2 2636\+
c1a54c05 2637 Matches 1 or more occurrences of pattern.
42fc5d26
QY
2638
2639?
c1a54c05 2640 Match 0 or 1 occurrences of pattern.
42fc5d26
QY
2641
2642^
c1a54c05 2643 Matches the beginning of the line.
42fc5d26
QY
2644
2645$
c1a54c05 2646 Matches the end of the line.
42fc5d26
QY
2647
2648_
8fcedbd2
QY
2649 The ``_`` character has special meanings in BGP regular expressions. It
2650 matches to space and comma , and AS set delimiter ``{`` and ``}`` and AS
2651 confederation delimiter ``(`` and ``)``. And it also matches to the
2652 beginning of the line and the end of the line. So ``_`` can be used for AS
2653 value boundaries match. This character technically evaluates to
2654 ``(^|[,{}()]|$)``.
42fc5d26 2655
42fc5d26 2656
c1a54c05 2657.. _bgp-configuration-examples:
42fc5d26 2658
8fcedbd2
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2659Miscellaneous Configuration Examples
2660====================================
42fc5d26 2661
9eb95b3b
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2662Example of a session to an upstream, advertising only one prefix to it.
2663
2664.. code-block:: frr
42fc5d26 2665
c1a54c05
QY
2666 router bgp 64512
2667 bgp router-id 10.236.87.1
2668 neighbor upstream peer-group
2669 neighbor upstream remote-as 64515
2670 neighbor upstream capability dynamic
2671 neighbor 10.1.1.1 peer-group upstream
2672 neighbor 10.1.1.1 description ACME ISP
c3c5a71f 2673
c1a54c05
QY
2674 address-family ipv4 unicast
2675 network 10.236.87.0/24
2676 neighbor upstream prefix-list pl-allowed-adv out
2677 exit-address-family
2678 !
2679 ip prefix-list pl-allowed-adv seq 5 permit 82.195.133.0/25
2680 ip prefix-list pl-allowed-adv seq 10 deny any
42fc5d26 2681
aa9eafa4
QY
2682A more complex example including upstream, peer and customer sessions
2683advertising global prefixes and NO_EXPORT prefixes and providing actions for
2684customer routes based on community values. Extensive use is made of route-maps
2685and the 'call' feature to support selective advertising of prefixes. This
2686example is intended as guidance only, it has NOT been tested and almost
2687certainly contains silly mistakes, if not serious flaws.
42fc5d26 2688
9eb95b3b 2689.. code-block:: frr
42fc5d26 2690
c1a54c05
QY
2691 router bgp 64512
2692 bgp router-id 10.236.87.1
2693 neighbor upstream capability dynamic
2694 neighbor cust capability dynamic
2695 neighbor peer capability dynamic
2696 neighbor 10.1.1.1 remote-as 64515
2697 neighbor 10.1.1.1 peer-group upstream
2698 neighbor 10.2.1.1 remote-as 64516
2699 neighbor 10.2.1.1 peer-group upstream
2700 neighbor 10.3.1.1 remote-as 64517
2701 neighbor 10.3.1.1 peer-group cust-default
2702 neighbor 10.3.1.1 description customer1
2703 neighbor 10.4.1.1 remote-as 64518
2704 neighbor 10.4.1.1 peer-group cust
2705 neighbor 10.4.1.1 description customer2
2706 neighbor 10.5.1.1 remote-as 64519
2707 neighbor 10.5.1.1 peer-group peer
2708 neighbor 10.5.1.1 description peer AS 1
2709 neighbor 10.6.1.1 remote-as 64520
2710 neighbor 10.6.1.1 peer-group peer
2711 neighbor 10.6.1.1 description peer AS 2
2712
2713 address-family ipv4 unicast
2714 network 10.123.456.0/24
2715 network 10.123.456.128/25 route-map rm-no-export
2716 neighbor upstream route-map rm-upstream-out out
2717 neighbor cust route-map rm-cust-in in
2718 neighbor cust route-map rm-cust-out out
2719 neighbor cust send-community both
2720 neighbor peer route-map rm-peer-in in
2721 neighbor peer route-map rm-peer-out out
2722 neighbor peer send-community both
2723 neighbor 10.3.1.1 prefix-list pl-cust1-network in
2724 neighbor 10.4.1.1 prefix-list pl-cust2-network in
2725 neighbor 10.5.1.1 prefix-list pl-peer1-network in
2726 neighbor 10.6.1.1 prefix-list pl-peer2-network in
2727 exit-address-family
2728 !
2729 ip prefix-list pl-default permit 0.0.0.0/0
2730 !
2731 ip prefix-list pl-upstream-peers permit 10.1.1.1/32
2732 ip prefix-list pl-upstream-peers permit 10.2.1.1/32
2733 !
2734 ip prefix-list pl-cust1-network permit 10.3.1.0/24
2735 ip prefix-list pl-cust1-network permit 10.3.2.0/24
2736 !
2737 ip prefix-list pl-cust2-network permit 10.4.1.0/24
2738 !
2739 ip prefix-list pl-peer1-network permit 10.5.1.0/24
2740 ip prefix-list pl-peer1-network permit 10.5.2.0/24
2741 ip prefix-list pl-peer1-network permit 192.168.0.0/24
2742 !
2743 ip prefix-list pl-peer2-network permit 10.6.1.0/24
2744 ip prefix-list pl-peer2-network permit 10.6.2.0/24
2745 ip prefix-list pl-peer2-network permit 192.168.1.0/24
2746 ip prefix-list pl-peer2-network permit 192.168.2.0/24
2747 ip prefix-list pl-peer2-network permit 172.16.1/24
2748 !
2749 ip as-path access-list asp-own-as permit ^$
2750 ip as-path access-list asp-own-as permit _64512_
2751 !
2752 ! #################################################################
2753 ! Match communities we provide actions for, on routes receives from
2754 ! customers. Communities values of <our-ASN>:X, with X, have actions:
2755 !
2756 ! 100 - blackhole the prefix
2757 ! 200 - set no_export
2758 ! 300 - advertise only to other customers
2759 ! 400 - advertise only to upstreams
2760 ! 500 - set no_export when advertising to upstreams
2761 ! 2X00 - set local_preference to X00
2762 !
2763 ! blackhole the prefix of the route
a64e0ee5 2764 bgp community-list standard cm-blackhole permit 64512:100
c1a54c05
QY
2765 !
2766 ! set no-export community before advertising
a64e0ee5 2767 bgp community-list standard cm-set-no-export permit 64512:200
c1a54c05
QY
2768 !
2769 ! advertise only to other customers
a64e0ee5 2770 bgp community-list standard cm-cust-only permit 64512:300
c1a54c05
QY
2771 !
2772 ! advertise only to upstreams
a64e0ee5 2773 bgp community-list standard cm-upstream-only permit 64512:400
c1a54c05
QY
2774 !
2775 ! advertise to upstreams with no-export
a64e0ee5 2776 bgp community-list standard cm-upstream-noexport permit 64512:500
c1a54c05
QY
2777 !
2778 ! set local-pref to least significant 3 digits of the community
a64e0ee5
DA
2779 bgp community-list standard cm-prefmod-100 permit 64512:2100
2780 bgp community-list standard cm-prefmod-200 permit 64512:2200
2781 bgp community-list standard cm-prefmod-300 permit 64512:2300
2782 bgp community-list standard cm-prefmod-400 permit 64512:2400
2783 bgp community-list expanded cme-prefmod-range permit 64512:2...
c1a54c05
QY
2784 !
2785 ! Informational communities
2786 !
2787 ! 3000 - learned from upstream
2788 ! 3100 - learned from customer
2789 ! 3200 - learned from peer
2790 !
a64e0ee5
DA
2791 bgp community-list standard cm-learnt-upstream permit 64512:3000
2792 bgp community-list standard cm-learnt-cust permit 64512:3100
2793 bgp community-list standard cm-learnt-peer permit 64512:3200
c1a54c05
QY
2794 !
2795 ! ###################################################################
2796 ! Utility route-maps
2797 !
2798 ! These utility route-maps generally should not used to permit/deny
2799 ! routes, i.e. they do not have meaning as filters, and hence probably
2800 ! should be used with 'on-match next'. These all finish with an empty
2801 ! permit entry so as not interfere with processing in the caller.
2802 !
2803 route-map rm-no-export permit 10
2804 set community additive no-export
2805 route-map rm-no-export permit 20
2806 !
2807 route-map rm-blackhole permit 10
f6aa36f5 2808 description blackhole, up-pref and ensure it cannot escape this AS
c1a54c05
QY
2809 set ip next-hop 127.0.0.1
2810 set local-preference 10
2811 set community additive no-export
2812 route-map rm-blackhole permit 20
2813 !
2814 ! Set local-pref as requested
2815 route-map rm-prefmod permit 10
2816 match community cm-prefmod-100
2817 set local-preference 100
2818 route-map rm-prefmod permit 20
2819 match community cm-prefmod-200
2820 set local-preference 200
2821 route-map rm-prefmod permit 30
2822 match community cm-prefmod-300
2823 set local-preference 300
2824 route-map rm-prefmod permit 40
2825 match community cm-prefmod-400
2826 set local-preference 400
2827 route-map rm-prefmod permit 50
2828 !
2829 ! Community actions to take on receipt of route.
2830 route-map rm-community-in permit 10
2831 description check for blackholing, no point continuing if it matches.
2832 match community cm-blackhole
2833 call rm-blackhole
2834 route-map rm-community-in permit 20
2835 match community cm-set-no-export
2836 call rm-no-export
2837 on-match next
2838 route-map rm-community-in permit 30
2839 match community cme-prefmod-range
2840 call rm-prefmod
2841 route-map rm-community-in permit 40
2842 !
2843 ! #####################################################################
2844 ! Community actions to take when advertising a route.
2845 ! These are filtering route-maps,
2846 !
2847 ! Deny customer routes to upstream with cust-only set.
2848 route-map rm-community-filt-to-upstream deny 10
2849 match community cm-learnt-cust
2850 match community cm-cust-only
2851 route-map rm-community-filt-to-upstream permit 20
2852 !
2853 ! Deny customer routes to other customers with upstream-only set.
2854 route-map rm-community-filt-to-cust deny 10
2855 match community cm-learnt-cust
2856 match community cm-upstream-only
2857 route-map rm-community-filt-to-cust permit 20
2858 !
2859 ! ###################################################################
2860 ! The top-level route-maps applied to sessions. Further entries could
2861 ! be added obviously..
2862 !
2863 ! Customers
2864 route-map rm-cust-in permit 10
2865 call rm-community-in
2866 on-match next
2867 route-map rm-cust-in permit 20
2868 set community additive 64512:3100
2869 route-map rm-cust-in permit 30
2870 !
2871 route-map rm-cust-out permit 10
2872 call rm-community-filt-to-cust
2873 on-match next
2874 route-map rm-cust-out permit 20
2875 !
2876 ! Upstream transit ASes
2877 route-map rm-upstream-out permit 10
2878 description filter customer prefixes which are marked cust-only
2879 call rm-community-filt-to-upstream
2880 on-match next
2881 route-map rm-upstream-out permit 20
2882 description only customer routes are provided to upstreams/peers
2883 match community cm-learnt-cust
2884 !
2885 ! Peer ASes
2886 ! outbound policy is same as for upstream
2887 route-map rm-peer-out permit 10
2888 call rm-upstream-out
2889 !
2890 route-map rm-peer-in permit 10
2891 set community additive 64512:3200
c3c5a71f 2892
8fcedbd2
QY
2893
2894Example of how to set up a 6-Bone connection.
2895
2896.. code-block:: frr
2897
2898 ! bgpd configuration
2899 ! ==================
2900 !
2901 ! MP-BGP configuration
2902 !
2903 router bgp 7675
2904 bgp router-id 10.0.0.1
2905 neighbor 3ffe:1cfa:0:2:2a0:c9ff:fe9e:f56 remote-as `as-number`
2906 !
2907 address-family ipv6
2908 network 3ffe:506::/32
2909 neighbor 3ffe:1cfa:0:2:2a0:c9ff:fe9e:f56 activate
2910 neighbor 3ffe:1cfa:0:2:2a0:c9ff:fe9e:f56 route-map set-nexthop out
2911 neighbor 3ffe:1cfa:0:2:2c0:4fff:fe68:a231 remote-as `as-number`
2912 neighbor 3ffe:1cfa:0:2:2c0:4fff:fe68:a231 route-map set-nexthop out
2913 exit-address-family
2914 !
2915 ipv6 access-list all permit any
2916 !
2917 ! Set output nexthop address.
2918 !
2919 route-map set-nexthop permit 10
2920 match ipv6 address all
2921 set ipv6 nexthop global 3ffe:1cfa:0:2:2c0:4fff:fe68:a225
2922 set ipv6 nexthop local fe80::2c0:4fff:fe68:a225
2923 !
2924 log file bgpd.log
2925 !
2926
2927
9e146a81 2928.. include:: routeserver.rst
f3817860
QY
2929
2930.. include:: rpki.rst
c1a54c05 2931
00458d01
PG
2932.. include:: flowspec.rst
2933
d1e7591e 2934.. [#med-transitivity-rant] For some set of objects to have an order, there *must* be some binary ordering relation that is defined for *every* combination of those objects, and that relation *must* be transitive. I.e.:, if the relation operator is <, and if a < b and b < c then that relation must carry over and it *must* be that a < c for the objects to have an order. The ordering relation may allow for equality, i.e. a < b and b < a may both be true and imply that a and b are equal in the order and not distinguished by it, in which case the set has a partial order. Otherwise, if there is an order, all the objects have a distinct place in the order and the set has a total order)
c1a54c05
QY
2935.. [bgp-route-osci-cond] McPherson, D. and Gill, V. and Walton, D., "Border Gateway Protocol (BGP) Persistent Route Oscillation Condition", IETF RFC3345
2936.. [stable-flexible-ibgp] Flavel, A. and M. Roughan, "Stable and flexible iBGP", ACM SIGCOMM 2009
2937.. [ibgp-correctness] Griffin, T. and G. Wilfong, "On the correctness of IBGP configuration", ACM SIGCOMM 2002