I am having trouble getting route redistribution into ISIS working. It works from ISIS to BGP, but I can't get the opposite to show up. I am using IOS-XR
Network has 3 routers:
A—-B—-C
A and B have an isis connection
B and C have a BGP connection
Router A has some 10.0.0.0 subnets that are shared with Rotuer B via ISIS. Router B is then passing these on to Router C with BGP, using the redistribute isis command.
Router C has a 192.168.56.0 subnet that is shared with Router B via BGP. Router B wants to share this with Router A via ISIS, but when I use the redistribute bpg command the route does not get added to the isis routes, and never shows on Router A.
I am not sure what I am doing wrong here.
Configuration for Router A (running IOS):
! trimmed, several interfaces with `ip router isis`
router isis
net 49.0000.0000.0000.0000.00
configuration for Router B (running IOS XR):
router isis 1
net 49.0000.1111.0000.0000.00
distribute bgp-ls
address-family ipv4 unicast
redistribute bgp 65000 level-1
!
interface GigabitEthernet0/0/0/0
address-family ipv4 unicast
!
!
interface GigabitEthernet0/0/0/1
address-family ipv4 unicast
!
!
!
router bgp 65000
bgp router-id 10.255.0.101
address-family ipv4 unicast
redistribute isis 1
!
neighbor 10.100.0.1
remote-as 65000
address-family ipv4 unicast
Configuration for Router C (running IOS XR):
router bgp 65000
bgp router-id 192.168.56.200
address-family ipv4 unicast
network 192.168.56.0/24
!
neighbor 10.100.0.2
remote-as 65000
address-family ipv4 unicast
!
!
On Router C running show route bgp
lists all of the routes from ISIS on A and B.
On Router B running show route isis
shows all of the ISIS provided routes I expect, and running show route bgp
shows the 192.168.56.0 route that I expect from C
On Router A the 192.168.56.0 route does not exist.
Best Answer
By default redistribution of IBGP into an IGP is disabled. To redistribute IBGP routes into an IGP, you need the command bgp redistribute-internal. Configuring this on B will inject BGP routes into ISIS.
More info here:https://www.cisco.com/c/en/us/td/docs/routers/xr12000/software/xr12k_r3-9/routing/configuration/guide/xr12krc39_chapter1.html