Layer 3 Routing Commands 1235Command ModeBGP Router Configuration modeUser GuidelinesThe BGP router ID must be a valid IPv4 unicast address, but is not requiredto be an address assigned to the router. The router ID is specified in thedotted notation of an IPv4 address. Changing the router ID disables and re-enables BGP, causing all adjacencies to be re-established.BGP is enabled by default once the administrator has specified the local ASnumber with the router bgp command and configured a router ID with thebgp router-id command.BGP is not operable until a BGP router ID has been assigned. The BGPadministrative state (as set by the enable command) has no operational effectuntil a router id is assigned to the BGP router.Command HistoryIntroduced in version 6.2.0.1 firmware.Exampleconsole(config-router)#bgp router-id 10.27.21.142clear ip bgpUse the clear ip bgp command to reset peering sessions with all of a subnet ofBGP peers. The command arguments specify which peering sessions are resetand the type of reset performed.Syntaxclear ip bgp [vrf vrf-name]{* | as-number | ipv4-address | ipv6-address [interface interface-id ] {listen range network/length}} [soft [in | out]]• vrf-name—This optional parameter identifies the VRF for which to resetpeering sessions. If not given, the default sessions are reset.• *— Reset adjacency with every BGP peer.• as-number— Only reset adjacencies with BGP peers in the givenautonomous system.
