doc/user/bmp.rst

   1 .. _bmp:
   2
   3 ***
   4 BMP
   5 ***
   6
   7 :abbr:`BMP` (BGP Monitoring Protocol, :rfc:`7854`) is used to send monitoring
   8 data from BGP routers to network management entities.
   9
  10 Implementation characteristics
  11 ==============================
  12
  13 The `BMP` implementation in FRR has the following properties:
  14
  15 - only the :rfc:`7854` features are currently implemented.  This means protocol
  16   version 3 without any extensions.  It is not possible to use an older draft
  17   protocol version of BMP.
  18
  19 - the following statistics codes are implemented:
  20
  21   - 0: count of prefixes rejected
  22   - 2: count of duplicate prefix withdrawals
  23   - 3: count of **prefixes** with loop in cluster id
  24   - 4: count of **prefixes** with loop in AS-path
  25   - 5: count of **prefixes** with loop in originator
  26   - 11: count of updates subjected to :rfc:`7607` "treat as withdrawal"
  27     handling due to errors
  28   - 65531: *experimental* count of prefixes rejected due to invalid next-hop
  29
  30   Note that stat items 3, 4 and 5 are specified to count updates, but FRR
  31   implements them as prefix-based counters.
  32
  33 - **route mirroring** is fully implemented, however BGP OPEN messages are not
  34   currently included in route mirroring messages.  Their contents can be
  35   extracted from the "peer up" notification for sessions that established
  36   successfully.  OPEN messages for failed sessions cannot currently be
  37   mirrored.
  38
  39 - **route monitoring** is available for IPv4 and IPv6 AFIs, unicast and
  40   multicast SAFIs.  Other SAFIs (VPN, Labeled-Unicast, Flowspec, etc.) are not
  41   currently supported.
  42
  43 - monitoring peers that have BGP **add-path** enabled on the session will
  44   result in somewhat unpredictable behaviour.  Currently, the outcome is:
  45
  46   - route mirroring functions as intended, messages are copied verbatim
  47   - the add-path ID is never included in route monitoring messages
  48   - if multiple paths were received from a peer, an unpredictable path is
  49     picked and sent on the BMP session.  The selection will differ for
  50     pre-policy and post-policy monitoring sessions.
  51   - as long as any path is present, something will be advertised on BMP
  52     sessions.  Only after the last path is gone a withdrawal will be sent on
  53     BMP sessions.
  54   - updates to additional paths will trigger BMP route monitoring messages.
  55     There is no guarantee on consistency regarding which path is sent in these
  56     messages.
  57
  58 - monitoring peers with :rfc:`5549` extended next-hops has not been tested.
  59
  60 Starting BMP
  61 ============
  62
  63 BMP is implemented as a loadable module.  This means that to use BMP, ``bgpd``
  64 must be started with the ``-M bmp`` option.  It is not possible to enable BMP
  65 if ``bgpd`` was started without this option.
  66
  67 Configuring BMP
  68 ===============
  69
  70 All of FRR's BMP configuration options are located inside the
  71 :clicmd:`router bgp ASN` block.  Configure BGP first before proceeding to BMP
  72 setup.
  73
  74 There is one option that applies to the BGP instance as a whole:
  75
  76 .. clicmd:: bmp mirror buffer-limit(0-4294967294)
  77
  78    This sets the maximum amount of memory used for buffering BGP messages
  79    (updates, keepalives, ...) for sending in BMP Route Mirroring.
  80
  81    The buffer is for the entire BGP instance; if multiple BMP targets are
  82    configured they reference the same buffer and do not consume additional
  83    memory.  Queue overhead is included in accounting this memory, so the
  84    actual space available for BGP messages is slightly less than the value
  85    configured here.
  86
  87    If the buffer fills up, the oldest messages are removed from the buffer and
  88    any BMP sessions where the now-removed messages were still pending have
  89    their **entire** queue flushed and a "Mirroring Messages Lost" BMP message
  90    is sent.
  91
  92    BMP Route Monitoring is not affected by this option.
  93
  94 All other configuration is managed per targets:
  95
  96 .. clicmd:: bmp targets NAME
  97
  98    Create/delete a targets group.  As implied by the plural name, targets may
  99    cover multiple outbound active BMP sessions as well as inbound passive
 100    listeners.
 101
 102    If BMP sessions have the same configuration, putting them in the same
 103    ``bmp targets`` will reduce overhead.
 104
 105 BMP session configuration
 106 -------------------------
 107
 108 Inside a ``bmp targets`` block, the following commands control session
 109 establishment:
 110
 111 .. clicmd:: bmp connect HOSTNAME port (1-65535) {min-retry MSEC|max-retry MSEC}
 112
 113    Add/remove an active outbound BMP session.  HOSTNAME is resolved via DNS,
 114    if multiple addresses are returned they are tried in nondeterministic
 115    order.  Only one connection will be established even if multiple addresses
 116    are returned.  ``min-retry`` and ``max-retry`` specify (in milliseconds)
 117    bounds for exponential backoff.
 118
 119 .. warning::
 120
 121    ``ip access-list`` and ``ipv6 access-list`` are checked for outbound
 122    connections resulting from ``bmp connect`` statements.
 123
 124 .. clicmd:: bmp listener <X:X::X:X|A.B.C.D> port (1-65535)
 125
 126    Accept incoming BMP sessions on the specified address and port.  You can
 127    use ``0.0.0.0`` and ``::`` to listen on all IPv4/IPv6 addresses.
 128
 129 .. clicmd:: ip access-list NAME
 130 .. clicmd:: ipv6 access-list NAME
 131
 132    Restrict BMP sessions to the addresses allowed by the respective access
 133    lists.  The access lists are checked for both passive and active BMP
 134    sessions.  Changes do not affect currently established sessions.
 135
 136 BMP data feed configuration
 137 ---------------------------
 138
 139 The following commands configure what BMP messages are sent on sessions
 140 associated with a particular ``bmp targets``:
 141
 142 .. clicmd:: bmp stats [interval (100-86400000)]
 143
 144    Send BMP Statistics (counter) messages at the specified interval (in
 145    milliseconds.)
 146
 147 .. clicmd:: bmp monitor AFI SAFI <pre-policy|post-policy>
 148
 149    Perform Route Monitoring for the specified AFI and SAFI.  Only IPv4 and
 150    IPv6 are currently valid for AFI, and only unicast and multicast are valid
 151    for SAFI.  Other AFI/SAFI combinations may be added in the future.
 152
 153    All BGP neighbors are included in Route Monitoring.  Options to select
 154    a subset of BGP sessions may be added in the future.
 155
 156 .. clicmd:: bmp mirror
 157
 158    Perform Route Mirroring for all BGP neighbors.  Since this provides a
 159    direct feed of BGP messages, there are no AFI/SAFI options to be
 160    configured.
 161
 162    All BGP neighbors are included in Route Mirroring.  Options to select
 163    a subset of BGP sessions may be added in the future.