[c-nsp] Multicast group but no traffic

Matthew Laughlin laughlinmd at gmail.com
Fri May 9 22:35:06 EDT 2014


Try adding a querier on the 2960.

Sent from my iPhone

On May 9, 2014, at 12:38 PM, Scott Voll <svoll.voip at gmail.com> wrote:

> VLC Player with TTL 10.  Connected to 3560 to Nexus 55xx with Layer 3.
> connection to 3845 over WAN to remote site, to 2911 to 2960 layer 2 switch.
> 
> I can see on Nexus, 3845 and 2911 the IP Mroute for the group I'm sending.
> Via a packet capture I can see the multicast local to the Nexus on
> multiple vlan's
> 
> I can see on the 2960 the groups and interfaces.  But a wire capture on the
> local PC all I see is the join packets, no traffic.
> 
> Other ideas?
> 
> Scott
> 
> 
> On Fri, May 9, 2014 at 11:28 AM, Phil Mayers <p.mayers at imperial.ac.uk>wrote:
> 
>> On 09/05/2014 18:53, Scott Voll wrote:
>> 
>>> I'm working on rolling out my Multicast across my WAN.
>>> 
>>> I can see the Multicast group on the WAN router and I can see it on the
>>> switch interface, but I'm not getting the traffic.  What should I be
>>> looking at?
>>> 
>> 
>> That's a bit vague. John has made some good suggestions but you'd get more
>> specific answers if you can specify the topology in detail.
>> 
>> How are you determining you're not "seeing" the traffic? No video at
>> receiver app? If so, check again with tcpdump/wireshark and look out for
>> software firewalls. That one catches me a lot - I always forget iptables on
>> my laptop :o(
>> 
>> "sh ip mr active" and "sh ip mr count" are useful at L3 hops. L2 hops are
>> far harder to debug, unfortunately.
>> 
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