Concept Guide

Example conguration for ltering routes with community lists
DellEMC# configure terminal
DellEMC(conf)# router bgp 400
DellEMC(conf-router_bgp)# neighbor 10.10.10.1 remote-as 500
DellEMC(conf-router_bgp)# neighbor 10.10.10.1 route-map route2 in
DellEMC(conf-router_bgp)# exit
DellEMC(conf)# route-map route2 permit 10
DellEMC(conf-route-map)# match community 1
DellEMC(conf-route-map)# set community 99
DellEMC(conf-route-map)# exit
DellEMC(conf)# ip community-list 1 permit 100
DellEMC(conf)# exit
DellEMC#
In the above example, add a BGP neighbor to the AS 400 and the route-map called route2 applied to inbound routes from the BGP
neighbor at 10.10.10.1. A route map route2 is created with a permit clause and the route’s community attribute is matched to communities
in community list 1. A community list 1 that permits routes with a communities attribute of 100.
To view the BGP conguration, use the show config command in CONFIGURATION ROUTER BGP mode. To view a route map
conguration, use the show route-map command in EXEC Privilege mode.
To view which BGP routes meet an IP community or IP extended community list’s criteria, use the show ip bgp {community-list
| extcommunity-list} command in EXEC Privilege mode.
Manipulating the COMMUNITY Attribute
A COMMUNITY attribute indicates that all the routes with that attribute belong to the same community grouping. In addition to permitting
or denying routes based on the values of the COMMUNITY attributes, you can manipulate the COMMUNITY attribute value and send the
COMMUNITY attribute with the route information.
By default, Dell EMC Networking OS does not send the COMMUNITY attribute to a BGP neighbor or a peer group.
To send the COMMUNITY attribute to BGP neighbors, use the following command.
• Enable the software to send the router’s COMMUNITY attribute to the BGP neighbor or peer group specied.
CONFIG-ROUTER-BGP mode
neighbor {ip-address | ipv6-address | peer-group-name} send-community [extended | standard]
extended- Allows to send the extended community attribute to a BGP neighbor or peer group.
standard- Allows to send the standard community attribute to a BGP neighbor or peer group.
To view the BGP conguration, use the show config command in CONFIGURATION ROUTER BGP mode.
If you want to remove or add a specic COMMUNITY number from a BGP path, you must create a route map with one or both of the
following statements in the route map. Then apply that route map to a BGP neighbor or peer group.
1 Enter ROUTE-MAP mode and assign a name to a route map.
CONFIGURATION mode
route-map map-name [permit | deny] [sequence-number]
2 Congure a set lter to delete all COMMUNITY numbers in the IP community list.
CONFIG-ROUTE-MAP mode
set comm-list community-list-name delete
OR
set community {community-number | local-as | no-advertise | no-export | none}
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Border Gateway Protocol (BGP)