Multicast across Subnets

[Jeff Horton]

I am having an issue with getting multicast video across subnets. I have vlan 10 (192.168.10.*) with multicast server 192.168.10.11..  I can see the video from vlan 200 (192.168.200.*) but not from any vlan that does not have the "192.168.*.*" subnet. (vlan 994 56.168.8.*). Any suggestions?

Switch files attached....

[Peter Paluch]

Jeff,

Your routing and PIM configuration seems to be set up properly. This is interesting. Can you please post the following two outputs from the externalsw while the streaming is active and there are subscribers in VLAN 994?

show ip mroute X.X.X.X
show ip igmp X.X.X.X

Substitute X.X.X.X with the multicast group address.

Best regards,
Peter

[Jeff Horton]

does not recognize command "show ip igmp X.X.X.X" on switch..

I have my laptop on g1/0/3 trying to access multicast video with VLC player....56.168.8.200..

so here is what I got:

Dbasesw#sh ip igmp snooping groups
Vlan      Group                    Type        Version     Port List
-----------------------------------------------------------------------
200       224.0.1.40               igmp        v2          Gi1/0/12
994       224.0.1.184              igmp        v2          Gi1/0/2
994       224.10.11.12             igmp        v2          Gi1/0/1
994       224.10.11.13             igmp        v2          Gi1/0/1
994       224.10.11.14             igmp        v2          Gi1/0/1
994       224.11.12.13             igmp        v2          Gi1/0/1
994       239.224.10.3             igmp        v2          Gi1/0/3
994       239.255.255.250          igmp        v2          Gi1/0/3
994       239.255.255.251          igmp        v2          Gi1/0/2

IBDbasesw#sh ip mroute 239.224.10.3
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,
       T - SPT-bit set, J - Join SPT, M - MSDP created entry, E - Extranet,
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
       U - URD, I - Received Source Specific Host Report,
       Z - Multicast Tunnel, z - MDT-data group sender,
       Y - Joined MDT-data group, y - Sending to MDT-data group,
       G - Received BGP C-Mroute, g - Sent BGP C-Mroute,
       N - Received BGP Shared-Tree Prune, n - BGP C-Mroute suppressed,
       Q - Received BGP S-A Route, q - Sent BGP S-A Route,
       V - RD & Vector, v - Vector, p - PIM Joins on route,
       x - VxLAN group
Outgoing interface flags: H - Hardware switched, A - Assert winner, p - PIM Join
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.224.10.3), 19:34:44/stopped, RP 192.168.200.2, flags: SP
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list: Null

(192.168.10.11, 239.224.10.3), 19:34:44/00:02:37, flags: PJT
  Incoming interface: Vlan200, RPF nbr 192.168.200.1, Mroute
  Outgoing interface list: Null

[Peter Paluch]

Jeff,

Thanks for the output. Please note that I asked for show ip igmp and not show ip igmp snooping - would you mind adding the output of show ip igmp as well please while the streaming is underway and a subscribed station exists in VLAN 994?

Best regards,
Peter

[Jeff Horton]

IBDbasesw#sh ip igmp 239.224.10.3
                                     ^
% Invalid input detected at '^' marker.

This is what I get when I run your command.....

[Peter Paluch]

Jeff,

No problem - would show ip igmp interface vlan 994 work?

Best regards,
Peter

[Jeff Horton]

IBDbasesw#sh ip igmp interface vlan 994
Vlan994 is up, line protocol is up
  Internet address is 56.168.8.253/24
  IGMP is enabled on interface
  Current IGMP host version is 2
  Current IGMP router version is 2
  IGMP query interval is 60 seconds
  IGMP configured query interval is 60 seconds
  IGMP querier timeout is 120 seconds
  IGMP configured querier timeout is 120 seconds
  IGMP max query response time is 10 seconds
  Last member query count is 2
  Last member query response interval is 1000 ms
  Inbound IGMP access group is not set
  IGMP activity: 298 joins, 289 leaves
  Multicast routing is enabled on interface
  Multicast TTL threshold is 0
  Multicast designated router (DR) is 56.168.8.254
  IGMP querying router is 56.168.8.253 (this system)
  Multicast groups joined by this system (number of users):
      224.0.1.40(1)

[Peter Paluch · Accepted solution]

Jeff,

Okay, notice this:

  Multicast designated router (DR) is 56.168.8.254

This device - whatever that is - is considered to be the Designated Router on this segment. It means that if a station sends an IGMP Join, it is this device, not your IBDbasesw, acting on this Join by attempting to build a multicast tree toward the RP. This may actually be the problem if the .254 device does not have information about reaching the privately addressed multicast source.

To make sure that the .253 wins the PIM DR elections, you will have to configure both .253 and .254 as follows:

! This is for .253
interface Vlan994
 ip pim dr-priority 200
end

! This is for .254
interface Vlan994
 ip pim dr-priority 100
end

The reason is that if one device has its priority configured and the other has not, the one without priority is still preferred in the DR elections.

Please check the following document for details about this command:

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti/command/imc-cr-book/imc_i3.html#wp1384657000

Would you mind testing this out?

Best regards,
Peter

[Jeff Horton]

I will test this and get back to you shortly.. In process of moving equipment around.

Jeff

[Jeff Horton]

I thank you for solving this problem.. I applied the recommended dr-priority and I am now able to view the video...

Another thing to add to my list of what to check when multicast issues arise..

Jeff Horton

[Peter Paluch]

Hi Jeff,

I am glad I could be of help.

Best regards,
Peter