BGP Monitoring Protocol Basics

BMP stations and associated parameters are configured in global configuration mode. This allows the BMP station to reside either within the base router instance, or in a VPRN routing instance. The Nokia BMP implementation can monitor BGP peers in a base Internet service or in a VPRN service instance.

BMP will initiate a separate TCP session for each VPRN BGP instance monitored. The BMP router will use a different source TCP port number toward each configured TCP destination port number of the BMP station. For example, if there are four VPRN services configured in addition to the base router instance, the BMP router will instantiate five TCP sessions between the BMP router and the BMP station (one TCP session to monitor the base router instance, and four TCP sessions to monitor the VPRN services).

SR OS supports the configuration of up to eight BMP stations. To configure a BMP station, use the following command syntax:

*A:Dut-C# configure bmp station Antwerp create

This configuration example creates a BMP station with the name "Antwerp". This name must be used when configuring BGP peers to be monitored by this station. The name can also be used in show router bmp commands.

The next step is to configure (at a minimum) the IP address and the TCP destination port the BMP station is listening to. These parameters inform the BMP router where to reach the BMP station. BMP does not use a well-known port number; a provider can select any TCP port number. BMP sessions from an SR OS router can run over either TCP IPv4 or TCP IPv6.

The following configures the IP address 100.1.1.10 and port number 5000 of the BMP station:

configure
    bmp
        station "Antwerp" create
            connection
                station-address 100.1.1.10 port 5000
            exit
        exit
    exit

This configuration example creates a BMP station that can be used to monitor one or more BGP peers. Next, configure the BGP peers to be monitored by this station.

To configure one or more BGP neighbors to be monitored by the BMP station, first configure the monitor command in the bgp context or one of its subcontexts. This command can be configured at the BGP instance level, at the BGP group level, or at the neighbor level.

In the following example, monitoring is enabled (no shutdown) for all BGP peers defined in the bgp context, where the BMP reporting goes to BMP station Antwerp.

configure
    router
        bgp
            monitor
                station Antwerp
                no shutdown
            exit
            group internal-1
              ---snip---
            Exit
            group internal-2
              ---snip---
            exit
        exit

By default, BMP, including each individually configured station, is in the administrative shutdown state. To allow BMP to start the BMP sessions, administratively enable the BMP station:

configure
    bmp
        no shutdown
        station Antwerp
            no shutdown
        exit
    exit

All peers in the BGP instance of the base router are now monitored by station "Antwerp". At this stage, the router will only send BMP peer-up and peer-down messages to the BMP station. To send additional information (such as periodic statistics messages, or to report incoming BGP routes) requires explicit configuration.

Enabling periodic statistics messages is done under the configure bmp station command. The command to enable periodic statistics is stats-report-interval <seconds>:

configure
    bmp
        station Antwerp
            stats-report-interval 600
        exit
    exit

This configuration example will cause the router to send statistics messages for each monitored peer to the BMP station every 10 minutes (600 seconds).

To display the state of a BMP session to a BMP station, use the show router bmp station <station-name> command:

show router bmp station Antwerp

The output of the show command for BMP station Antwerp is as follows:

*A:Dut-C# show router bmp station "Antwerp"

===============================================================================
BMP Station "Antwerp" (monitoring router "Base")
===============================================================================
Admin State      : enabled              Global BMP State : enabled
Station Address  : 100.1.1.10           Station Port     : 5000
Via Router       : Base
Stats Report     : 30 seconds
Connect Interval : 5 seconds            Local Routes     : not reporting
Reported families: ipv4

Session State    : ESTABLISHED          Last State Change: 08/29/2018 13:23:19
Reason Last Down : admin shutdown       Last Msg Sent    : 08/29/2018 13:23:19
Local Address    : 100.1.1.3            Local Port       : 51446
Routes Timer     : 2 seconds left       Stats Timer      : 3 seconds left
Connect Timer    : not running          Monitored Peers  : 0 of 1
Initiation Msgs  : 1                    Goodbye Msgs     : 0
Peer Up Msgs     : 0                    Peer Down Msgs   : 0
Route Report Msgs: 0                    Stat Report Msgs : 0
Bytes Sent       : 276                  Output Queue     : 0/5
===============================================================================
*A:Dut-C#

The output consists of two blocks of information.

• The first block shows configuration information about this specific BMP station.

• The second block shows dynamic information about the current BMP session from the router instance to the BMP station.

Verify that the Session State is "ESTABLISHED".

Configuring BMP route monitoring requires explicit configuration under the monitor command in the BGP instance context.

It is possible to configure BMP to report pre-policy routes, or post-policy routes, or both. Pre-policy routes are incoming routes as they were before applying any ingress policy. Post-policy routes are resulting routes in the Adj-RIB-In and reflect the routes after applying any BGP ingress policy.

Configuring BMP to report both pre- and post-policy routes will result in the doubling of BMP messages to the BMP station. This is because the router will send a route-monitor message for each pre-policy route, and for each post-policy route. This doubles the amount of resources consumed by BMP (such as bandwidth consumed on the link between the router and the BMP station, and CPU usage). The impact of enabling BMP route monitoring on the router CPU is similar to adding a BGP neighbor.

To configure route monitoring, use the route-monitoring [pre-policy] [post-policy] command in the monitor configuration mode in the BGP configuration context:

configure
    router
        bgp
            monitor
                station Antwerp
                route-monitoring pre-policy
                no shutdown
            exit
        exit

The BMP route monitoring is enabled within the context where the monitor station command is configured: in the general bgp context, the group context, or the neighbor context. With this configuration, the BMP router will start sending route monitoring messages for every route received from every neighbor in the base router BGP instance. This can be verified via the show router bmp station <station-name> command, which displays the counter for "Route Report Msgs:".

When route monitoring is enabled, by default the BMP router will only report received IPv4 routes to the BMP station. This aligns with the default BGP behavior, where only unicast IPv4 is enabled when configuring a neighbor under BGP. To enable route monitoring for additional BGP address families, additional explicit configuration is required. The additional address families are available and can be configured under the configure bmp station command context, as follows:

configure
    bmp
        station Antwerp
            family 
        exit
    exit

In SR OS Release 16.0.R1, a Nokia BMP router supports route monitoring of six address families:

• unicast IPv4, unicast IPv6

• VPN-IPv4, VPN-IPv6

• label-IPv4, label-IPv6

SR OS Release 16.0.R4 provides an additional six address families:

• EVPN

• L2VPN

• mcast-IPv4, mcast-IPv6

• mcast-VPN-IPv4, mcast-VPN-IPv6

RFC 7854 BMP reports only the routes in the Adj-RIB-In that were received from monitored neighbors. However, the BGP-RIB can hold more routes than those routes BGP has learned from neighbors. These locally generated routes are called imported or leaked routes.

Imported routes are learned via redistributing routes into BGP from external sources, like static, connected, IS-IS, or OSPF. Leaked routes are BGP routes from other BGP service instances that are leaked into the base router BGP.

To configure the Nokia BMP router to extend route reporting and report these imported and leaked routes to a configured BMP station, configure the report-local-routes command under the BMP station:

configure 
    bmp
        station Antwerp
            report-local-routes
        exit
    exit

When periodic statistics are enabled, the router will send all the statistics as described in RFC 7854, section 4.8, except for statistic number 13 (number of duplicate update messages received).

The Nokia BMP router-supported statistics are:

• 0 - number of prefixes rejected by inbound policy

• 1 - number of duplicate prefix advertisements received

• 2 - number of duplicate withdraws received

• 3 - number of received updates invalidated due to cluster-list loop

• 4 - number of received updates invalidated due to AS-path loop

• 5 - number of received updates invalidated due to originator-id

• 6 - number of received updates invalidated due to as-confed loop

• 7 - total number of routes in Adj-RIB-In (all families)

• 8 - total number of routes in loc-RIB (all families)

• 9 - number of routes per address family in Adj-RIB-In (see Note)

• 10 - number of routes per address family in loc-RIB (see Note)

• 11 - number of updates subjected to treat-as-withdraw

• 12 - number of prefixes subjected to treat-as-withdraw

• 13 - not supported/reported by SR OS (number of duplicate update messages received)

The values shown in the preceding counters are the same values that are shown by the show router <vrid> bgp neighbor <ip-addr> [detail] command.

BMP uses TCP sessions to send BMP messages to the BMP station. It is possible to customize the TCP-session settings using several configuration options. These options are under the configure bmp station <name> connection command context.