On IOS-XR, the Auto-RP configuration is roughly similar. The Auto-RP groups appear to already be in the “listening” mode by default. The XRv forwards this in dense mode without any extra configuration.
On the edge routers in the domains running BSR, we must use the bsr-border feature to filter BSR messages in/out of the interface.
# XR2
router pim
add ipv4
int GigabitEthernet0/0/0/0.524
bsr-border
int GigabitEthernet0/0/0/0.562
bsr-border
# CSR6
int GigabitEthernet2.562
ip pim bsr-border
int GigabitEthernet2.569
ip pim bsr-border
To filter Auto-RP messages, we must filter the multicast traffic for the group itself. Auto-RP is not a control message as in BSR (which uses PIM). We can filter the contents of the Auto-RP message using ip multicast boundary filter-autorp ACL on IOS-XE, but this command does not allow us to filter the messages altogether. Instead, we must use a general multicast boundary filter and deny the Auto-RP groups.
# XR4
multicast-routing
add ipv4
int GigabitEthernet0/0/0/0.524
boundary DENY_AUTORP
int GigabitEthernet0/0/0/0.594
boundary DENY_AUTORP
!
ipv4 access-list DENY_AUTORP
10 deny ipv4 any host 224.0.1.39
20 deny ipv4 any host 224.0.1.40
30 permit ipv4 any any
Verification
Use the command show ip pim rp mapping on all routers to verify the correct RP is learned in each domain.
AS 7:
AS 8:
AS 9:
AS 11:
Within AS 7, verify that the two edge routers are not forwarding Auto-RP traffic out their inter-AS links.
Above, the AB flag means “administrative boundary.” The interface has forwarding disabled due to the IPv4 ACL we applied as a multicast boundary.
