[c-nsp] Multicast group but no traffic

[John Kougoulos]

Hi,

just a few debugging ideas:

You could put an ACL on 2911 outbound interface to 2960 an ACL like
permit ip any host 239.xxx.xx.xx (the multicast group)
permit ip any any

and check if you get counters increasing on the first line

you could also enable ip flow and then with show ip cache flow see if the
multicast traffic arrives there

Check on show ip igmp snooping if 2960 has discovered the correct multicast
router, and in any case disable igmp snooping  on this vlan to see if this
blocks your traffic

What are the multicast packet counters on 2960 interfaces show?

Regards,
John



On Fri, May 9, 2014 at 9:38 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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