cisco ios xr multicast

[adir-Malka]

We are currently facing an issue while trying to configure MVPN on a Cisco NSX540 running IOS XR.

Our goal is to establish multicast VPN (MVPN) between PE routers. We have followed Cisco’s configuration guides and ensured that both unicast routing and multicast (PIM) are configured properly. However, the multicast traffic is not being forwarded through the VRF, and the MVPN tunnels (MDT ) are not coming up as expected.

We have verified:
- multicast routing between PE and P routers is working correctly.
- PIM is enabled on all core interfaces.
- The VRF configuration includes the correct RD/RT values.
- MPLS and LDP sessions are up.

Still, the MVPN instance does not seem to activate or exchange routes.

Has anyone encountered a similar issue on NSX540 with IOS XR?
Any suggestions or configuration examples would be greatly appreciated.

[Enes Simnica]

gDay @adir-Malka Had this happen before, and in my case the issue was that the Mdtwasn’t being created because the default MDT group wasn’t defined under the VRF. So what I did on the ios xr is this; 

multicast-routing
 address-family ipv4
  mdt default.....

Once I added that and made sure the P routers could join that multicast group, the MDT came up right away.

Also back then i had some more issues, deeper ones, if u wanna know what happened the full story, let me know G hehe

hope it helps and PEACE!!!

-Enes

[adir-Malka]

hey, thank you for the reply. i would like to know what happened in your environment.

- Adir

[Enes Simnica]

absolutely @adir-Malka my G, lets gOOOO:

After adding the default MDT group under the VRF, the tunnels finally started showing up, but multicast traffic still wasn’t flowing through the VPN. Turned out I had a couple of issues layered together: 1.One PE had the wrong MDT source interface; it was using a loopback that wasn’t advertised in the core IGP, so the other routers couldn’t join the multicast group. 2. PIM wasn’t enabled on one of the core-facing interfaces, which broke the multicast distribution tree even though unicast and MPLS were fine, and 3. I also realized that the MDT data group wasn’t defined, so even after the default MDT came up, the high-bandwidth multicast streams weren’t switching over correctly.

Once I fixed the MDT source to a reachable loopback, enabled PIM on all core links, and redefined both default and data MDTs, everything came up smoothly. I cleared the PIM neighbors and MDT sessions, and I could literally see the tunnels rebuild in real time. And in that moment I realized that I need more coffee (hahahah! it wasnt funny   ) 

and some more issues that i cant share here,,..... So thats it.... 

-Enes

[M02@rt37]

Hello @adir-Malka 

Could you please share the specific configurations ? Both PE and P routers please !

[tkarnani]

for profile 0 please see the configuration, be mindful of the core-tree config in xr

--

https://www.cisco.com/c/en/us/td/docs/iosxr/ncs5xx/multicast/74x/b-mcast-cg-74x-ncs540/m-implementing-layer-3-multicast-router-ncs5xx.html#Cisco_Concept.dita_542fe516-42dc-4fd3-b919-2c58b137737b

from the guide

Router# configure
Router(config)# route-policy rosen-gre
Router(config-rpl)#  set core-tree pim-default
Router(config-rpl)# end-policy

Router(config)# multicast-routing
Router(config-mcast)# vrf vpn101
Router(config-mcast-vpn101)# address-family ipv4
Router(config-mcast-vpn101-ipv4)#  mdt source Loopback0
Router(config-mcast-vpn101-ipv4)#   mdt default ipv4 232.100.0.1
Router(config-mcast-vpn101-ipv4)#   mdt data 232.101.0.1/24 
Router(config-mcast-vpn101-ipv4)#   interface all enable

Router(config)# router pim
Router(config-pim)# address-family ipv4
Router(config-pim-default-ipv4)# vrf vpn101
Router(config-pim-vpn101)#  address-family ipv4
Router(config-pim-vpn101-ipv4)#   rpf topology route-policy rosen-gre
Router(config-pim-vpn101-ipv4)#   exit
Router(config-pim-vpn101-ipv4)# commit

[adir-Malka]

"Hi, could you please send me the BGP configurations as well?"

[adir-Malka]

"Hi, could you please send me the BGP configurations as well?"