I have an iBGP session between a Juniper router and a Cisco IOS XR router with add-path/additional-path both in send and receive direction enabled. According to show bgp neighbor
, the feature is operating properly in both routers. In the IOS XR router there is a 10.2.34.0/24
prefix with next-hop to 172.16.0.33
and 172.16.0.44
:
RP/0/RP0/CPU0:RR2#sh bgp ipv4 unicast 10.2.34.0/24 brief
Wed Apr 21 10:55:09.050 UTC
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
* i10.2.34.0/24 172.16.0.33 200 100 0 65002 i
*>i 172.16.0.44 100 100 0 65002 i
* i 172.16.0.33 200 100 0 65002 i
* i 172.16.0.44 100 100 0 65002 i
RP/0/RP0/CPU0:RR2#
However, for some reason, only the best path is advertised to Juniper router:
RP/0/RP0/CPU0:RR2#sh bgp neighbor 172.16.0.11 advertised-routes
Wed Apr 21 10:56:45.760 UTC
Network Next Hop From AS Path
10.1.12.0/24 172.16.0.202 172.16.0.11 65001i
10.2.34.0/24 172.16.0.44 172.16.0.44 65002i
192.168.10.1/32 172.16.0.202 172.16.0.11 65001i
192.168.10.2/32 172.16.0.22 172.16.0.22 65001i
192.168.20.3/32 172.16.0.33 172.16.0.33 65002i
192.168.20.4/32 172.16.0.44 172.16.0.44 65002i
Processed 6 prefixes, 6 paths
RP/0/RP0/CPU0:RR2#
I would expect the IOS XR router to advertise two copies of 10.2.34.0/24
prefix with different path IDs and different next-hop addresses(172.16.0.33
and 172.16.0.44
). Detailed information for 10.2.34.0/24
prefix in IOS XR router can be seen below:
Path #1: Received by speaker 0
Not advertised to any peer
65002, (Received from a RR-client)
172.16.0.33 (metric 20) from 172.16.0.33 (172.16.0.33)
Origin IGP, metric 200, localpref 100, valid, internal
Received Path ID 1, Local Path ID 0, version 0
Path #2: Received by speaker 0
Advertised IPv4 Unicast paths to update-groups (with more than one peer):
0.2 0.3
Advertised IPv4 Unicast paths to peers (in unique update groups):
172.16.0.201
65002, (Received from a RR-client)
172.16.0.44 (metric 20) from 172.16.0.44 (172.16.0.44)
Origin IGP, metric 100, localpref 100, valid, internal, best, group-best
Received Path ID 1, Local Path ID 1, version 17
BGP configuration of the IOS XR router can be seen below:
RP/0/RP0/CPU0:RR2#sh run router bgp
Thu Apr 22 08:17:17.814 UTC
router bgp 65000
address-family ipv4 unicast
additional-paths receive
additional-paths send
!
neighbor-group iBGP-RR1
remote-as 65000
update-source Loopback0
address-family ipv4 unicast
!
!
neighbor-group iBGP-CLIENTS
remote-as 65000
cluster-id 172.16.0.202
update-source Loopback0
address-family ipv4 unicast
route-reflector-client
!
!
neighbor 172.16.0.11
use neighbor-group iBGP-CLIENTS
!
neighbor 172.16.0.22
use neighbor-group iBGP-CLIENTS
!
neighbor 172.16.0.33
use neighbor-group iBGP-CLIENTS
!
neighbor 172.16.0.44
use neighbor-group iBGP-CLIENTS
!
neighbor 172.16.0.201
use neighbor-group iBGP-RR1
!
!
RP/0/RP0/CPU0:RR2#
Is there a reason why IOS XR router does not advertise two copies of 10.2.34.0/24
route?
additional-path
feature is that the IOS XR router should advertise at least two copies of the10.2.34.0/24
prefix with different next hop values(172.16.0.33
&172.16.0.44
) and path IDs. @RonTrunk I added the BGP configuration.