Dmz Link Bandwidth Over Ebgp Peer; Peer - Cisco NCS 5500 Series Configuration Manual

Implementing BGP
route-policy pass-all in
route-policy pass-all out
!
!
neighbor 11.11.16.12
remote-as 200
dmz-link-bandwidth
address-family ipv4 unicast
route-policy pass-all in
route-policy pass-all out
!
!
neighbor 11.11.17.12
remote-as 200
dmz-link-bandwidth
address-family ipv4 unicast
route-policy pass-all in
route-policy pass-all out
!
!
neighbor 11.11.18.12
remote-as 200
dmz-link-bandwidth
address-family ipv4 unicast
route-policy pass-all in
route-policy pass-all out
!
!
!
end

DMZ Link Bandwidth Over EBGP Peer

The demilitarized zone (DMZ) link bandwidth extended community is an optional non-transitive attribute;
therefore, it is not advertised to eBGP peers by default but it is advertised only to iBGP peers. This extended
community is meant for load balancing over multi-paths. However, Cisco IOS-XR enables advertising of the
DMZ link bandwidth to an eBGP peer, or receiving the DMZ link bandwidth by an eBGP peer. This feature
also gives the user the option to send the bandwidth unchanged, or take the accumulated bandwidth over all
the egress links and advertise that to the upstream eBGP peer.
Use the ebgp-send-community-dmz command to send the community to eBGP peers. By default, the link
bandwidth extended-community attribute associated with the best path is sent.
When the cumulative keyword is used, the value of the link bandwidth extended community is set to the sum
of link bandwidth values of all the egress-multipaths. If the DMZ link bandwidth value of the multipaths is
unknown, for instance, some paths do not have that attribute, then unequal cost load-balancing is not done at
that node. However, the sum of the known DMZ link bandwidth values is calculated and sent to the eBGP

peer.

Use the ebgp-recv-community-dmz command to receive the community from eBGP peers.
Note The ebgp-send-community-dmz and ebgp-recv-community-dmz commands can be configured in
the neigbor, neighbour-group, and session-group configuration mode.
Use the bgp bestpath as-path multipath-relaxand bgp bestpath as-path ignore commands to handle
multipath across different autonomous systems.
BGP Configuration Guide for Cisco NCS 5500 Series Routers, IOS XR Release 6.2.x
Enable BGP Unequal Cost Recursive Load Balancing
87