Reference Guide

Border Gateway Protocol | 159
Enable additional paths
By default, the add-path feature is disabled.
Use the following command in the CONFIGURATION ROUTER BGP mode to allow multiple paths sent
to peers.
Configure IP community lists
Within FTOS, you have multiple methods of manipulating routing attributes. One attribute you can
manipulate is the COMMUNITY attribute. This attribute is an optional attribute that is defined for a group
of destinations. In FTOS, you can assign a COMMUNITY attribute to BGP routers by using an IP
Community list. After you create an IP Community list, you can apply routing decisions to all routers
meeting the criteria in the IP Community list.
IETF RFC 1997 defines the COMMUNITY attribute and the pre-defined communities of INTERNET,
NO_EXPORT_SUBCONFED, NO_ADVERTISE, and NO_EXPORT. All BGP routes belong to the
INTERNET community. In the RFC, the other communities are defined as follows:
• All routes with the NO_EXPORT_SUBCONFED (0xFFFFFF03) community attribute are not sent to
CONFED-EBGP or EBGP peers, but are sent to IBGP peers within CONFED-SUB-AS.
redistribute isis [level-1 |
level-1-2 | level-2] [metric value]
[
route-map map-name]
ROUTER BGP or
CONF-ROUTER_BGPv6_AF
Include specific ISIS routes in BGP. Configure
the following parameters:
• level-1, level-1-2, or level-2: Assign all
redistributed routes to a level. Default is
level-2.
• metric range: 0 to 16777215. Default is 0.
• map-name: name of a configured route map.
redistribute ospf process-id
[match external {1 | 2} | match
internal] [metric-type {external |
internal}] [route-map
map-name]
ROUTER BGP or
CONF-ROUTER_BGPv6_AF
Include specific OSPF routes in IS-IS. Configure
the following parameters:
• process-id range: 1 to 65535
• match external range: 1 or 2
• match internal
• metric-type: external or internal.
• map-name: name of a configured route map.
Step Command Syntax Command Mode Purpose
1 bgp add-path
[both|received|send]
path-count <count>
CONFIG-ROUTER-BGP Allow the advertisement of multiple paths for the
same address prefix without the new paths
replacing any previous ones.
Range: 2-64
2 neighbor add-path CONFIG-ROUTER-BGP Allow the specified neighbor/peer group to send/
receive multiple path advertisements.
Command Syntax Command Mode Purpose