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FTOS Configuration Guide for the C-Series - Force10 Networks

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<strong>FTOS</strong> MBGP is implemented as per IETF RFC 1858. The MBGP feature can be enabled per router and/or<br />

per peer/peer-group. Default is IPv4 Unicast routes.<br />

Command Syntax Command Mode Purpose<br />

address family ipv4 multicast CONFIG-ROUTER-BGP<br />

neighbor [ip-address |<br />

peer-group-name] activate<br />

CONFIG-ROUTER-BGP-AF<br />

(Address Family)<br />

When a peer is configured to support IPv4 Multicast, <strong>FTOS</strong> takes <strong>the</strong> following actions:<br />

• Send a capacity advertisement to <strong>the</strong> peer in <strong>the</strong> BGP Open message specifying IPv4 Multicast as a<br />

supported AFI/SAFI (Subsequent Address Family Identifier).<br />

• If <strong>the</strong> corresponding capability is received in <strong>the</strong> peer’s Open message, BGP will mark <strong>the</strong> peer as<br />

supporting <strong>the</strong> AFI/SAFI.<br />

• When exchanging updates with <strong>the</strong> peer, BGP sends and receives IPv4 Multicast routes if <strong>the</strong> peer is<br />

marked as supporting that AFI/SAFI.<br />

• Exchange of IPv4 Multicast route in<strong>for</strong>mation occurs through <strong>the</strong> use of two new attributes called<br />

MP_REACH_NLRI and MP_UNREACH_NLRI, <strong>for</strong> feasible and withdrawn routes, respectively.<br />

• If <strong>the</strong> peer has not been activated in any AFI/SAFI, <strong>the</strong> peer remains in Idle state.<br />

Most <strong>FTOS</strong> BGP IPv4 Unicast commands are extended to support <strong>the</strong> IPv4 Multicast RIB using extra<br />

options to <strong>the</strong> command. See <strong>the</strong> <strong>FTOS</strong> Command Line Interface Reference <strong>for</strong> a detailed description of <strong>the</strong><br />

MBGP commands.<br />

BGP Regular Expression Optimization<br />

Enables support <strong>for</strong> <strong>the</strong> IPv4 Multicast<br />

family on <strong>the</strong> BGP node<br />

Enable IPv4 Multicast support on a<br />

BGP neighbor/peer group<br />

BGP policies that contain regular expressions to match against as-paths and communities might take a lot<br />

of CPU processing time, thus affect BGP routing convergence. Also, show bgp commands that get<br />

filtered through regular expressions can to take a lot of CPU cycles, especially when <strong>the</strong> database is large.<br />

<strong>FTOS</strong> optimizes processing time when using regular expressions by caching and re-using regular<br />

expression evaluated results, at <strong>the</strong> expense of some memory in RP1 processor. This feature is turned on by<br />

default. Use <strong>the</strong> command bgp regex-eval-optz-disable in CONFIGURATION ROUTER BGP<br />

mode to disable it if necessary.<br />

<strong>FTOS</strong> <strong>Configuration</strong> <strong>Guide</strong>, version 7.7.1.0 515

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