BGP Selective Download

BGP-SD, use a route-map (table-map) to filter which BGP routes are installed into FIB (currently only supported for the IPv4 unicast GRT address-family, for VPNv4 address-family routes all routes are installed into FIB).

1st Note:
When the table-map command is used without the filter keyword, the route map referenced in the table-map command is used to set certain properties (such as the traffic index) of the routes for installation into the RIB. The route is always downloaded, regardless of whether it is permitted or denied by the route map.

When the table-map command is used with the filter keyword, the route map referenced is also used to control whether a BGP route is to be downloaded to the RIB (hence the filter). A BGP route is not downloaded to the RIB if it is denied by the route map.

2nd Note:
When using a table-map to partially filter bgp-to-fib updates, any routes required for path next-hop reachability must be allowed in if the next-hop isn't in the IGP.

PE1:

ip prefix-list LOOPBACK-PREFIXES seq 5 permit 10.0.0.0/24 ge 32

route-map ALLLOW-LOOPBACKS permit 10
 match ip address prefix-list LOOPBACK-PREFIXES
 set community 65000:65000

router bgp 6000
 address-family ipv4 unicast
  redistribute connected route-map ALLLOW-LOOPBACKS


RR:

ip community-list 100 permit 65000:65000

route-map BGP-TO-RIB-LOOPBACKS permit 10
 match community 100

router bgp 65000
 address-family ipv4 unicast
  table-map bgp-to-rib filter

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