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Cannot multicast across routers

jmmendez.cbt
Level 1
Level 1

Hello everyone, I'm in trouble with multicast.

Topology is DC (Data center routers) connected via /30 with Core connected via /30 with access switch. All of them are 6500 and, as you can imagine, DC is an access layer too, only it connects servers.

Multicast is configured as "sparse-mode".

Connected to DC are a couple DCMs acting as multicast sources for our IPTV system. at access layer we've IPTVs and user computers (that can tune a channel with VLC using the mcast IP address).

 

As part of an experiment I'm trying to source a video, using VLC, from my PC. Problem is I can only get what I'm streaming in other PCs in the same vlan, but not on other access switches (other floors).

 

So, on vlan11 I can only receive  multicast video streams, but can't generate there (tried 2 different access swithces).

can you help? Thank you!

1 Accepted Solution

Accepted Solutions

Everyone, thank you so much for you assistance. Problem was VLC streaming with a TTL=1, despite explicit setting for ttl=12.

Found it with wireshark on my pc

View solution in original post

7 Replies 7

johnd2310
Level 8
Level 8

Hi,

 

Is the core your RP? what is the output of the following:  "show ip mroute"on the RP?

what is the ttl of the multicast stream?

 

Thanks

John

**Please rate posts you find helpful**

yes, the core router (it's actually a pair) have anycast rp set at loopback 1.
show ip mroute shows me a (*,G) and a (S,G) for each group which source is the DCM at the DC and nothing for the one I'm generating from the access

what is the ttl of the multicast stream from the vlc Thanks John
**Please rate posts you find helpful**

ttl = 12

 

EDIT

Also, please note that if I try to tune that stream I'm generating from my computer I get a (*,G) entry in the access router (whether is the one my computer is attached to, or another access router) and at the core router. But I never get the (S,G) entry showing my IP as the source.

 

EDIT2

Just in case it's relevant, the SVI configuration in access switches include a helper-address, while the SVI at the DC, does not. I did read that it may affect something, but don't really know.

Hi,
If you are not receiving multicast traffic in the hosts connected to the other switches (while receiving on the switch where you have the source), it could be due to "IGMP Snooping". Please look at the following solutions:
https://www.cisco.com/c/en/us/support/docs/switches/catalyst-6500-series-switches/68131-cat-multicast-prob.html

HTH,
Meheretab
HTH,
Meheretab

Interface VLAN does have the pim command enabled, so I'm trying to stream on a L3 environment

Everyone, thank you so much for you assistance. Problem was VLC streaming with a TTL=1, despite explicit setting for ttl=12.

Found it with wireshark on my pc

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