222 | Border Gateway Protocolw w w . d e l l . c o m | s u p p o r t . d e l l . c o m If you want to remove or add a specific COMMUNITY number from a BGP path, you must create a routemap with one or both of the following statements in the route map. Then apply that route map to a BGPneighbor or peer group. Use these commands in the following sequence, starting in theCONFIGURATION mode:To view the BGP configuration, use the show config command in CONFIGURATION ROUTER BGPmode. To view a route map configuration, use the show route-map command in EXEC Privilege mode.Use the show ip bgp community command in EXEC Privilege mode (Figure 9-29) to view BGP routesmatching a certain community number or pre-defined BGP community.Step Command Syntax Command Mode Purpose1 route-map map-name[permit | deny][sequence-number]CONFIGURATION Enter the ROUTE-MAP mode and assign a nameto a route map.2 set comm-listcommunity-list-namedeleteCONFIG-ROUTE-MAP Configure a set filter to delete all COMMUNITYnumbers in the IP Community list.set community{community-number |local-as | no-advertise |no-export | none}CONFIG-ROUTE-MAP Configure a Community list by denying orpermitting specific community numbers or typesof community• community-number: use AA:NN formatwhere AA is the AS number (2 or 4 Bytes) andNN is a value specific to that autonomoussystem.• local-AS: routes with the COMMUNITYattribute of NO_EXPORT_SUBCONFED andare not sent to EBGP peers.• no-advertise: routes with the COMMUNITYattribute of NO_ADVERTISE and are notadvertised.• no-export: routes with the COMMUNITYattribute of NO_EXPORT.• none: remove the COMMUNITY attribute.• additive: add the communities to alreadyexisting communities.3 exit CONFIG-ROUTE-MAP Return to the CONFIGURATION mode.4 router bgp as-number CONFIGURATION Enter the ROUTER BGP mode.5 neighbor {ip-address |peer-group-name}route-map map-name {in| out}CONFIG-ROUTER-BGP Apply the route map to the neighbor or peergroup’s incoming or outgoing routes.
