multicast across GRE tunnel

[jmfranco]

We are deploying a IPTV solution for one internal department into our core. In one side of our core we will have one TV encoder, and in the other hand of our core we will have TV decoders. Because our core doesn't support multicast routing at this momment, provisionally we will install two cisco routers, one of them on the LAN TV encoder side, and the other on the LAN TV decoders side, configuring a tunnel interface between them. By this way, multicast routing will be routed across tunnel interface, and unicast routing will be routed across lan routing.

Ok, we have configured them with pim dense mode, adding an ip mroute in decoders router side pointing to multicast source network and multicast routing works fine.

Now we want to try to configure this environment with pim sparse mode, and it doesn't work. Here you have simplified configuration from both routers in sparse mode:

ENCODER SIDE ROUTER

--------------------

interface Tunnel1

ip address 10.211.251.74 255.255.255.252

ip accounting output-packets

ip pim sparse-dense-mode

load-interval 30

tunnel source FastEthernet0/0

tunnel destination 10.0.71.210

tunnel path-mtu-discovery

!

interface FastEthernet0/0

ip address 10.0.6.18 255.255.255.248

ip pim sparse-dense-mode

load-interval 30

duplex auto

speed auto

ip pim rp-address 10.0.6.18 99

ip mroute 10.0.70.0 255.255.254.0 Tunnel1

access-list 99 permit 239.8.1.2 0.0.0.1

DECODERS SIDE ROUTER

--------------------

interface Tunnel1

ip address 10.211.251.73 255.255.255.252

ip pim sparse-dense-mode

load-interval 30

tunnel source FastEthernet0/0

tunnel destination 10.0.6.18

tunnel path-mtu-discovery

!

interface FastEthernet0/0

ip address 10.0.71.210 255.255.254.0

ip accounting output-packets

ip pim sparse-dense-mode

ip igmp join-group 239.8.1.2

load-interval 30

duplex auto

speed auto

ip pim rp-address 10.0.6.18 99

ip mroute 10.0.6.16 255.255.255.248 tunnel1

access-list 99 permit 239.8.1.2 0.0.0.1

At this momment TV encoder has only one tv channel transmiting into 239.8.1.2 multicast group.

Taking a view to show commands I post, we think the problem is not rpf failure. In "show ip mroute 239.8.1.2 count" command output from encoder side router, you can see continously drops due (OIF-null, etc.) But what is the problem? Anybody can help us?

[Giuseppe Larosa]

Hello Juan,

this sounds better.

I had the wrong impression they were two routers in back to back by looking at the configurations you posted.

My previous post is out of context in this case: your tests are meaningful.

And yes bad surprises are always possible even after a careful lab testing.

About PIM: means protocol independent multicast that only means indipendency from a specific unicast routing protocol not from the whole ip routing table.

In your case a picture could have helped us to understand what you were doing: I guess you have used the internal lan for the GRE tunnels while I was thinking at interface to the core.

Best Regards

Giuseppe

[Harold Ritter]

Juan,

Glad you got it working and that the keepalives helped you realized that there was a connectivity issue between the two tunnel end points.

Feliz año nuevo