Trouble configuring multicast routing

[Iulian Vaideanu]

I seem to be unable to properly configure the 7304 (R2) router in the attached drawing so that the RECeiver can have access to the 224.6.0.101 group.  The only multicast-related configuration on Gi0.981 and Gi.989 is "ip pim sparse-mode", and basicly what I'm puzzled about is the output of the "show ip mroute 224.6.0.101 (count)" command(s) on R2:

(*, 224.6.0.101), 01:13:26/00:02:59, RP 0.0.0.0, flags: SP

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list: Null

Group: 224.6.0.101, Source count: 0, Packets forwarded: 0, Packets received: 85377

  RP-tree: Forwarding: 0/0/0/0, Other: 85377/85377/0

I mean, why is the route pruned, and why the RPF failed counters (the router and the source being directly connected)?

The RECeiver also has access to some 224.5.0.x groups behind router R1, and when I configured "ip pim sparse-mode" on Gi0.989 of router R1, all the traffic belonging to those 224.5.0.x groups started pouring into Gi0 of R1.  Is there any way to avoid that?

[Lei Tian]

Hi,

No RP configured from the output?

(*, 224.6.0.101), 01:13:26/00:02:59, RP 0.0.0.0, flags: SP

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list: Null

HTH,

Lei Tian

[Iulian Vaideanu]

mcast-router#sh ip pim rp 224.6.0.101

Group: 224.6.0.101, RP: 0.0.0.0

I'd like to think that this is the simplest multicast routing setup possible (one router passing multicast traffic from one (sub)interface to another), but could the presence of R1 somehow "affect" the 224.6.0.101 group?

[Lei Tian]

Hi,

The receiver is not directly connected to R2. You need RP. Change that to dense mode, see if you can get the traffic.

HTH,
Lei Tian

Sent from Cisco Technical Support iPhone App

[paul driver]

Hello

For pim sparse-mode you need a RP specifed be it autorp or static.

sh ip pim rp mapping

static rp (on all routers)

ip pim rp address x.x.x.x

autorp

conf t

int lo0
ip address 1.1.1.1 255.255.255.255

ip pim spare-mode

exit

ip pim send-rp-announce 1.1.1.1 scope 10
ip pim send-rp-discovery Loopback0 scope 10

All pim sparse enable routers need to be able to reach defind rp address specifed

res

Paul

Please don't forget to rate any posts that have been helpful.

Thanks.

[Iulian Vaideanu]

Here's what I did:

access-list 22 permit 224.6.0.101

ip pim rp-address 192.168.81.254 22

(I know a loopback is recommended, but I think a (sub)interface address isn't forbidden either).  Now I have:

(*, 224.6.0.101), 00:01:53/stopped, RP 192.168.81.254, flags: SP

  Incoming interface: Null, RPF nbr 0.0.0.0

  Outgoing interface list: Null

(192.168.81.1, 224.6.0.101), 00:01:53/00:02:53, flags: PT

  Incoming interface: GigabitEthernet0.981, RPF nbr 0.0.0.0

  Outgoing interface list: Null

Group: 224.6.0.101, Source count: 1, Packets forwarded: 0, Packets received: 4773

  RP-tree: Forwarding: 0/0/0/0, Other: 0/0/0

  Source: 192.168.81.1/32, Forwarding: 0/-21/0/0, Other: 4773/0/4773

What could be wrong this time?

[Lei Tian]

Hi ,

Your receiver is not directly connected. You either config the RP on the receiver 's default gateway, or change to dense mode.

The state tells you the router receives the multicast but don't know where to send it.

HTH,
Lei Tian

Sent from Cisco Technical Support iPhone App

[Iulian Vaideanu]

I'll try that as well, but this requirement of IP reachability to the receiver brings another question:  R1 is not under my administration, but I do know the config of its interface towards my Vl989, and it only contains "ip pim sparse-mode" and "ip multicast boundary" - however, I can access the 224.5.0.x groups with any computer connected to Vlan989, no matter the IP address.  Is there any other config bit that the admin of R1 might have used in order to allow me to do that?