Technical Documentation

Enabling BGP

To enable BGP on the routing device, perform the following tasks:

Specifying the Local Routing Device’s AS Number

Each routing device running BGP must be configured with its AS number. This number is included in the local AS number field in BGP open messages, which are sent between BGP peers to establish a connection.

To specify an AS number, include the autonomous-system statement:

autonomous-system autonomous-system <loops number>;

For a list of hierarchy levels at which you can include this statement, see the statement summary section for this statement.

You must specify an AS number to enable BGP.

For more information about configuring the AS number, see Configuring AS Numbers for BGP.

Defining an AS Confederation and Its Members

To enable the local system to participate as a member of an AS confederation, you must define the AS confederation identifier and specify the AS numbers that are members of the confederation. To do this, include the confederation statement:

confederation confederation-autonomous-system members [ autonomous-systems ];

For a list of hierarchy levels at which you can include this statement, see the statement summary section for this statement.

Defining an AS confederation and its members is optional.

For more information about configuring confederations, see Configuring AS Confederation Members.

Assigning a BGP Identifier

Each routing device running BGP must have a BGP identifier. This identifier is included in the BGP identifier field of open messages, which are sent between two BGP peers when establishing a BGP session.

Explicitly assigning a BGP identifier is optional. If you do not assign one, the IP address of the first interface encountered in the routing device is used.

To assign a BGP identifier explicitly, include the router-id statement:

router-id address;

For a list of hierarchy levels at which you can include this statement, see the statement summary section for this statement.

Assigning a BGP identifier is optional.

For more information, see Configuring Router Identifiers for BGP and OSPF.

Defining BGP Global Properties

To define BGP global properties, which apply to all BGP groups and peers, include one or more of the following statements. These statements are explained in separate sections.

accept-remote-nexthop;advertise-external <conditional>;advertise-inactive;(advertise-peer-as | no-advertise-peer-as);authentication-algorithm algorithm;authentication-key key;authentication-key-chain key-chain;bfd-liveness-detection {authentication {algorithm algorithm-name;key-chain key-chain-name;loose-check;}detection-time {threshold milliseconds;}holddown-interval milliseconds;minimum-interval milliseconds;minimum-receive-interval milliseconds;no-adaptation;transmit-interval {threshold milliseconds;minimum-interval milliseconds;}multiplier number;no-adaptation;version (1 | automatic);}cluster cluster-identifier;damping;description text-description;disable;export [ policy-names ];family {(inet | inet6 | inet-vpn | inet6-vpn | iso-vpn) {(any | flow | labeled-unicast | multicast | unicast) {accepted-prefix-limit {maximum number;teardown <percentage> <idle-timeout (forever | minutes)>;}<loops number>;prefix-limit {maximum number;teardown <percentage> <idle-timeout (forever | minutes)>;}rib-group group-name;}flow {no-validate policy-name;}labeled-unicast {accepted-prefix-limit {maximum number;teardown <percentage> <idle-timeout (forever | minutes)>;}aggregate-label {community community-name:}explicit-null {connected-only;}prefix-limit {maximum number;teardown <percentage> <idle-timeout (forever | minutes)>;}resolve-vpn;rib inet.3;rib-group group-name;}}route-target {accepted-prefix-limit {maximum number;teardown <percentage> <idle-timeout (forever | minutes)>;}advertise-default;external-paths number;prefix-limit {maximum number;teardown <percentage> <idle-timeout (forever | minutes)>;}}(inet-mdt | inet-mvpn | inet6-mvpn | l2-vpn) {signaling {accepted-prefix-limit {maximum number;teardown <percentage> <idle-timeout (forever | minutes)>;}<loops number>;prefix-limit {maximum number;teardown <percentage> <idle-timeout (forever | minutes)>;}rib-group group-name}}}graceful-restart {disable;restart-time seconds;stale-routes-time seconds;}group group-name {... group-specific-options ...}hold-time seconds;idle-after-switch-over (seconds | forever);import [ policy-names ];include-mp-next-hop;ipsec-sa ipsec-sa;keep (all | none);local-address address;local-as autonomous-system <private>;local-interface interface-name;local-preference local-preference;log-updown;metric-out (metric | minimum-igp <offset> | igp <offset>);mtu-discovery;multihop {no-nexthop-change;ttl value;}no-advertise-peer-as;no-aggregator-id;no-client-reflect;out-delay seconds;outbound-route-filter{bgp-orf-cisco-mode;prefix-based {accept {(inet | inet6);}}}passive;path-selection {(always-compare-med | cisco-non-deterministic | external-router-id);med-plus-igp {igp-multiplier number;med-multiplier number;}}peer-as autonomous-system;preference preference;remove-private;tcp-mss segment-size;traceoptions {file filename <files number> <size size> <world-readable | no-world-readable>;flag flag <flag-modifier> <disable>;}vpn-apply-export;

For a list of hierarchy levels at which you can include these statements, see the statement summary sections for these statements.

You must configure BGP global properties to enable BGP.

Related Topics

Published: 2010-07-02

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