common capabilities, FRR sends Unsupported Capability error and then resets the
connection.
-.. _bgp-concepts-vrfs:
-
-VRFs: Virtual Routing and Forwarding
-------------------------------------
-
-*bgpd* supports :abbr:`L3VPN (Layer 3 Virtual Private Networks)` :abbr:`VRFs
-(Virtual Routing and Forwarding tables)` for IPv4 :rfc:`4364` and IPv6
-:rfc:`4659`. L3VPN routes, and their associated VRF MPLS labels, can be
-distributed to VPN SAFI neighbors in the *default*, i.e., non VRF, BGP
-instance. VRF MPLS labels are reached using *core* MPLS labels which are
-distributed using LDP or BGP labeled unicast. *bgpd* also supports inter-VRF
-route leaking. General information on FRR's VRF support can be found in
-:ref:`zebra-vrf`.
-
.. _bgp-router-configuration:
BGP Router Configuration
not enabled *bgpd* can't get interface information so `router-id` is set to
0.0.0.0. So please set router-id by hand.
+
+.. _bgp-multiple-autonomous-systems:
+
+Multiple Autonomous Systems
+---------------------------
+
+FRR's BGP implementation is capable of running multiple autonomous systems at
+once. Each configured AS corresponds to a :ref:`zebra-vrf`. In the past, to get
+the same functionality the network administrator had to run a new *bgpd*
+process; using VRFs allows multiple autonomous systems to be handled in a
+single process.
+
+When using multiple autonomous systems, all router config blocks after the
+first one must specify a VRF to be the target of BGP's route selection. This
+VRF must be unique within respect to all other VRFs being used for the same
+purpose, i.e. two different autonomous systems cannot use the same VRF.
+However, the same AS can be used with different VRFs.
+
+.. note::
+
+ The separated nature of VRFs makes it possible to peer a single *bgpd*
+ process to itself, on one machine. Note that this can be done fully within
+ BGP without a corresponding VRF in the kernel or Zebra, which enables some
+ practical use cases such as :ref:`route reflectors <bgp-route-reflector>`
+ and route servers.
+
+Configuration of additional autonomous systems, or of a router that targets a
+specific VRF, is accomplished with the following command:
+
+.. index:: router bgp ASN vrf VRFNAME
+.. clicmd:: router bgp ASN vrf VRFNAME
+
+ ``VRFNAME`` is matched against VRFs configured in the kernel. When ``vrf
+ VRFNAME`` is not specified, the BGP protocol process belongs to the default
+ VRF.
+
+An example configuration with multiple autonomous systems might look like this:
+
+.. code-block:: frr
+
+ router bgp 1
+ neighbor 10.0.0.1 remote-as 20
+ neighbor 10.0.0.2 remote-as 30
+ !
+ router bgp 2 vrf blue
+ neighbor 10.0.0.3 remote-as 40
+ neighbor 10.0.0.4 remote-as 50
+ !
+ router bgp 3 vrf red
+ neighbor 10.0.0.5 remote-as 60
+ neighbor 10.0.0.6 remote-as 70
+ ...
+
+In the past this feature done differently and the following commands were
+required to enable the functionality. They are now deprecated.
+
+.. deprecated:: 5.0
+ This command is deprecated and may be safely removed from the config.
+
+.. index:: bgp multiple-instance
+.. clicmd:: bgp multiple-instance
+
+ Enable BGP multiple instance feature. Because this is now the default
+ configuration this command will not be displayed in the running
+ configuration.
+
+.. deprecated:: 5.0
+ This command is deprecated and may be safely removed from the config.
+
+.. index:: no bgp multiple-instance
+.. clicmd:: no bgp multiple-instance
+
+ In previous versions of FRR, this command disabled the BGP multiple instance
+ feature. This functionality is automatically turned on when BGP multiple
+ instances or views exist so this command no longer does anything.
+
+.. seealso:: :ref:`bgp-vrf-route-leaking`
+.. seealso:: :ref:`zebra-vrf`
+
+
+.. _bgp-views:
+
+Views
+-----
+
+In addition to supporting multiple autonomous systems, FRR's BGP implementation
+also supports *views*.
+
+BGP views are almost the same as normal BGP processes, except that routes
+selected by BGP are not installed into the kernel routing table. Each BGP view
+provides an independent set of routing information which is only distributed
+via BGP. Multiple views can be supported, and BGP view information is always
+independent from other routing protocols and Zebra/kernel routes. BGP views use
+the core instance (i.e., default VRF) for communication with peers.
+
+.. index:: router bgp AS-NUMBER view NAME
+.. clicmd:: router bgp AS-NUMBER view NAME
+
+ Make a new BGP view. You can use an arbitrary word for the ``NAME``. Routes
+ selected by the view are not installed into the kernel routing table.
+
+ With this command, you can setup Route Server like below.
+
+ .. code-block:: frr
+
+ !
+ router bgp 1 view 1
+ neighbor 10.0.0.1 remote-as 2
+ neighbor 10.0.0.2 remote-as 3
+ !
+ router bgp 2 view 2
+ neighbor 10.0.0.3 remote-as 4
+ neighbor 10.0.0.4 remote-as 5
+
+.. index:: show [ip] bgp view NAME
+.. clicmd:: show [ip] bgp view NAME
+
+ Display the routing table of BGP view ``NAME``.
+
+
Route Selection
---------------
specified number of hops away will be allowed to become neighbors. This
command is mutually exclusive with *ebgp-multihop*.
+.. index:: [no] neighbor PEER capability extended-nexthop
+.. clicmd:: [no] neighbor PEER capability extended-nexthop
+
+ Allow bgp to negotiate the extended-nexthop capability with it's peer.
+ If you are peering over a v6 LL address then this capability is turned
+ on automatically. If you are peering over a v6 Global Address then
+ turning on this command will allow BGP to install v4 routes with
+ v6 nexthops if you do not have v4 configured on interfaces.
+
+.. index:: [no] bgp fast-external-failover
+.. clicmd:: [no] bgp fast-external-failover
+
+ This command causes bgp to not take down ebgp peers immediately
+ when a link flaps. `bgp fast-external-failover` is the default
+ and will not be displayed as part of a `show run`. The no form
+ of the command turns off this ability.
+
.. _bgp-peer-filtering:
Peer Filtering
``0xFFFF0006`` ``65535:6``.
Assigned and intented only for use with routers supporting the
Long-lived Graceful Restart Capability as described in
- :rfc:`draft-uttaro-idr-bgp-persistence`.
+ [Draft-IETF-uttaro-idr-bgp-persistence]_.
Routers recieving routes with this community may (depending on
implementation) choose allow to reject or modify routes on the
presence or absence of this community.
``0xFFFF0007`` ``65535:7``.
Assigned and intented only for use with routers supporting the
Long-lived Graceful Restart Capability as described in
- :rfc:`draft-uttaro-idr-bgp-persistence`.
+ [Draft-IETF-uttaro-idr-bgp-persistence]_.
Routers recieving routes with this community may (depending on
implementation) choose allow to reject or modify routes on the
presence or absence of this community.
``accept-own-nexthop``
``accept-own-nexthop`` represents well-known communities value
``accept-own-nexthop`` ``0xFFFF0008`` ``65535:8``.
- :rfc:`draft-agrewal-idr-accept-own-nexthop` describes
+ [Draft-IETF-agrewal-idr-accept-own-nexthop]_ describes
how to tag and label VPN routes to be able to send traffic between VRFs
via an internal layer 2 domain on the same PE device. Refer to
- :rfc:`draft-agrewal-idr-accept-own-nexthop` for full details.
+ [Draft-IETF-agrewal-idr-accept-own-nexthop]_ for full details.
``blackhole``
``blackhole`` represents well-known communities value ``BLACKHOLE``
When the communities attribute is received duplicate community values in the
attribute are ignored and value is sorted in numerical order.
+.. [Draft-IETF-uttaro-idr-bgp-persistence] <https://tools.ietf.org/id/draft-uttaro-idr-bgp-persistence-04.txt>
+.. [Draft-IETF-agrewal-idr-accept-own-nexthop] <https://tools.ietf.org/id/draft-agrewal-idr-accept-own-nexthop-00.txt>
+
.. _bgp-community-lists:
Community Lists
This command defines a new expanded community list. ``COMMUNITY`` is a
string expression of communities attribute. ``COMMUNITY`` can be a regular
expression (:ref:`bgp-regular-expressions`) to match the communities
- attribute in BGP updates.
+ attribute in BGP updates. The expanded community is only used to filter,
+ not `set` actions.
.. deprecated:: 5.0
It is recommended to use the more explicit versions of this command.
If ``none`` is specified as the community value, the communities attribute
is not sent.
+ It is not possible to set an expanded community list.
+
.. index:: set comm-list WORD delete
.. clicmd:: set comm-list WORD delete
This command set Site of Origin value.
+
+Note that the extended expanded community is only used for `match` rule, not for
+`set` actions.
+
.. _bgp-large-communities-attribute:
Large Communities Attribute
large-community list. The third will add a large-community value without
overwriting other values. Multiple large-community values can be specified.
+Note that the large expanded community is only used for `match` rule, not for
+`set` actions.
-.. _bgp-vrfs:
+.. _bgp-l3vpn-vrfs:
-VRFs
-----
+L3VPN VRFs
+----------
-BGP supports multiple VRF instances with the following command:
-
-.. index:: router bgp ASN vrf VRFNAME
-.. clicmd:: router bgp ASN vrf VRFNAME
+*bgpd* supports :abbr:`L3VPN (Layer 3 Virtual Private Networks)` :abbr:`VRFs
+(Virtual Routing and Forwarding)` for IPv4 :rfc:`4364` and IPv6 :rfc:`4659`.
+L3VPN routes, and their associated VRF MPLS labels, can be distributed to VPN
+SAFI neighbors in the *default*, i.e., non VRF, BGP instance. VRF MPLS labels
+are reached using *core* MPLS labels which are distributed using LDP or BGP
+labeled unicast. *bgpd* also supports inter-VRF route leaking.
-``VRFNAME`` is matched against VRFs configured in the kernel. When
-``vrf VRFNAME`` is not specified, the BGP protocol process belongs to the
-default VRF.
-With VRF, you can isolate networking information. Having BGP VRF allows you to
-have several BGP instances on the same system process. This solution solves
-scalabiliy issues where the network administrator had previously to run
-separately several BGP processes on each namespace. Now, not only BGP VRF
-solves this, but also this method applies to both kind of VRFs backend: default
-VRF from Linux kernel or network namespaces. Also, having separate BGP
-instances does not imply that the AS number has to be different. For internal
-purposes, it is possible to do iBGP peering from two differents network
-namespaces.
+.. _bgp-vrf-route-leaking:
VRF Route Leaking
-^^^^^^^^^^^^^^^^^
+-----------------
BGP routes may be leaked (i.e. copied) between a unicast VRF RIB and the VPN
SAFI RIB of the default VRF for use in MPLS-based L3VPNs. Unicast routes may
to VPN.
Required parameters
-"""""""""""""""""""
+^^^^^^^^^^^^^^^^^^^
Routes exported from a unicast VRF to the VPN RIB must be augmented by two
parameters:
auto-derived.
General configuration
-"""""""""""""""""""""
+^^^^^^^^^^^^^^^^^^^^^
Configuration of route leaking between a unicast VRF RIB and the VPN SAFI RIB
of the default VRF is accomplished via commands in the context of a VRF
Disables automatic leaking from vrf VRFNAME to the current VRF using
the VPN RIB as intermediary.
-.. _bgp-instances-and-views:
-
-Instances and Views
--------------------
-
-A BGP *instance* is a normal BGP process. Routes selected by BGP are installed
-into the kernel routing table.
-
-.. note::
- In previous versions of FRR, running multiple AS's from the same BGP process
- was not supported; in order to run multiple AS's it was necessary to run
- multiple BGP processes. This had to be explicitly configured with the
- ``bgp multiple-instance`` command. Recent versions of FRR support multiple
- BGP AS's within the same process by simply defining multiple
- ``router bgp X`` blocks, so the ``multiple-instance`` command is now
- unnecessary and deprecated.
-
-.. index:: router bgp AS-NUMBER
-.. clicmd:: router bgp AS-NUMBER
-
- Make a new BGP instance. You can use an arbitrary word for the `name`.
-
- .. code-block:: frr
-
- router bgp 1
- neighbor 10.0.0.1 remote-as 2
- neighbor 10.0.0.2 remote-as 3
- !
- router bgp 2
- neighbor 10.0.0.3 remote-as 4
- neighbor 10.0.0.4 remote-as 5
-
-.. deprecated:: 5.0
- This command does nothing and can be safely removed.
-
-.. index:: bgp multiple-instance
-.. clicmd:: bgp multiple-instance
-
- Enable BGP multiple instance feature. Because this is now the default
- configuration this command will not be displayed in the running
- configuration.
-
-.. deprecated:: 5.0
- This command does nothing and can be safely removed.
-
-.. index:: no bgp multiple-instance
-.. clicmd:: no bgp multiple-instance
-
- In previous versions of FRR, this command disabled the BGP multiple instance
- feature. This functionality is automatically turned on when BGP multiple
- instances or views exist so this command no longer does anything.
-
-BGP views are almost same as normal BGP processes, except that routes selected
-by BGP are not installed into the kernel routing table. The view functionality
-allows the exchange of BGP routing information only without affecting the
-kernel routing tables.
-
-.. index:: router bgp AS-NUMBER view NAME
-.. clicmd:: router bgp AS-NUMBER view NAME
-
- Make a new BGP view. You can use arbitrary word for the ``NAME``. Routes selected by the view are not installed into the kernel routing table.
- view's route selection result does not go to the kernel routing table.
-
- With this command, you can setup Route Server like below.
-
- .. code-block:: frr
-
- !
- router bgp 1 view 1
- neighbor 10.0.0.1 remote-as 2
- neighbor 10.0.0.2 remote-as 3
- !
- router bgp 2 view 2
- neighbor 10.0.0.3 remote-as 4
- neighbor 10.0.0.4 remote-as 5
-
-.. index:: show [ip] bgp view NAME
-.. clicmd:: show [ip] bgp view NAME
-
- Display the routing table of BGP view ``NAME``.
.. _bgp-cisco-compatibility:
projects / mirror_frr.git / blobdiff