I am trying to setup multicast over GRE tunnels between a pair of Hub routers to a spoke router. These are connected over an MPLS network that does not support multicast. The requirement is to have unicast work normally via MPLS and use CE to CE GRE tunnels only for multicast traffic. Multicast works fine when I create the GRE tunnel from the spoke to only one of the Hub routers and use a static default mroute pointing to Tunnel interface. But when I create a backup tunnel to a second Hub router, multicast is not working.
Since we can configure only one static mroute to 0.0.0.0 in Cisco IOS, I am using following workaround configuration on the Spoke router
!
interface Tunnel100
description To primary Hub router
ip address 100.64.0.213 255.255.255.252
ip pim sparse-mode
keepalive 2 3
tunnel source 100.64.0.211
tunnel destination 100.64.0.210
!
interface Tunnel200
description To secondary Hub router
ip address 100.64.0.230 255.255.255.252
ip pim sparse-mode
keepalive 2 3
tunnel source 100.64.0.225
tunnel destination 100.64.0.226
!
ip mroute 0.0.0.0 0.0.0.0 1.1.1.1
!
ip route 1.1.1.1 255.255.255.255 100.64.0.214 200
ip route 1.1.1.1 255.255.255.255 100.64.0.229 210
!
ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/0 192.188.32.1 200 (192.188.32.1 is WAN IP towards MPLS cloud)
!
ip pim rp-address 100.64.0.209
However, when I do an RPF check for the Source or RP address, it fails.
#show ip rpf 100.64.0.209
failed, no route exists
RPF check only succeeds for the Tunnel IPs
#show ip rpf 100.64.0.214
RPF information for ? (100.64.0.214)
RPF interface: Tunnel100
RPF neighbor: ? (100.64.0.214) - directly connected
RPF route/mask: 100.64.0.212/30
RPF type: multicast (connected)
Doing distance-preferred lookups across tables
RPF topology: ipv4 multicast base
#
Need to troubleshoot why RPF is failing here.
This configuration is supposed to work as per
ftp://ftpeng.cisco.com/ipmulticast/config-notes/gre-tunnel.txt
Please advise
Thanks
