Cisco NCS 6000 Series User Manual

Configurations applied on the Border Router
Configure a route policy that matches the community set on the trigger router and configure set next-hop
discard:
route-policy RTBH
if community matches-any (1234:4321) then
set next-hop discard
else
pass
endif
end-policy
Apply the route policy on the iBGP peers:
router bgp 65001
address-family ipv4 unicast
!
neighbor 192.168.102.2
remote-as 65001
address-family ipv4 unicast
route-policy RTBH in
route-policy bgp_all out
Verification
On the border router, the prefix 10.7.7.7/32 is flagged as Nexthop-discard:
RP/0/RSP0/CPU0:router#show bgp
BGP router identifier 10.210.0.5, local AS number 65001
BGP generic scan interval 60 secs
BGP table state: Active
Table ID: 0xe0000000 RD version: 12
BGP main routing table version 12
BGP scan interval 60 secs
Status codes: s suppressed, d damped, h history, * valid, > best
i - internal, r RIB-failure, S stale, N Nexthop-discard
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
N>i10.7.7.7/32 192.168.102.2 0 100 0 ?
RP/0/RSP0/CPU0:router#show bgp 10.7.7.7/32
BGP routing table entry for 10.7.7.7/32
Versions:
Process bRIB/RIB SendTblVer
Speaker 12 12
Last Modified: Jul 4 14:37:29.048 for 00:20:52
Paths: (1 available, best #1, not advertised to EBGP peer)
Not advertised to any peer
Path #1: Received by speaker 0
Not advertised to any peer
Local
192.168.102.2 (discarded) from 192.168.102.2 (10.210.0.2)
Origin incomplete, metric 0, localpref 100, valid, internal best, group-best
Received Path ID 0, Local Path ID 1, version 12
Community: 1234:4321 no-export
RP/0/RSP0/CPU0:router#show route 10.7.7.7/32
Routing entry for 10.7.7.7/32
Known via "bgp 65001", distance 200, metric 0, type internal
Installed Jul 4 14:37:29.394 for 01:47:02
Routing Configuration Guide for Cisco NCS 6000 Series Routers, IOS XR Release 6.4.x
36
Implementing BGP
Verification

Cisco NCS 6000 Series Specifications

General

Brand	Cisco
Model	NCS 6000 Series
Category	Network Router
Language	English