Administrator Guide

• process-id: the range is from 1 to 65535.
• match external: the range is from 1 or 2.
• match internal
• metric-type: external or internal.
• map-name: name of a configured route map.
Enabling Additional Paths
The add-path feature is disabled by default.
NOTE: Note: In some cases, while receiving 1K same routes from more than 64 iBGP neighbors, BGP
sessions holdtime of 10 seconds may flap. The BGP add-path does not update packets for advertisement
and cannot scale to higher numbers. Either reduce the number of routes added or increase the holddown
timer value.
To allow multiple paths sent to peers, use the following commands.
1 Allow the advertisement of multiple paths for the same address prefix without the new paths replacing
any previous ones.
CONFIG-ROUTER-BGP mode
bgp add-path [send | receive | both] count
The range is from 2 to 64.
2 Allow the specified neighbor/peer group to send/ receive multiple path advertisements.
CONFIG-ROUTER-BGP mode
neighbor add-path
3 Configure the maximum number of parallel routes (multipath support) BGP supports.
CONFIG-ROUTER-BGP mode
max-path number
The range is from 2 to 64.
Configuring IP Community Lists
Within the Dell Networking OS, 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. 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 predefined 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.
• All routes with the NO_ADVERTISE (0xFFFFFF02) community attribute must not be advertised.
Border Gateway Protocol IPv4 (BGPv4) 232