[c-nsp] igmp snooping inside 802.1q trunks

[Vladimir Ivashchenko]

I traced multicast streams that were being sent to trunks without
receivers and found that they were coming from a different switch than
the querier. Is flooding expected in such cases?

> Are you seeing snooping entries for the MAC? 0100.5e40.00xx (sh mac- 
> multi igmp) If so, what is the port mask? You are sure it is 
> 239.192.0.x & not 239.128.0.x? The latter would map to a reserved 
> range MAC, & we won't install a snooping mac entry for it, it will
> flood....
> 
> Tim
> 
> At 10:19 AM 1/31/2006, Vladimir Ivashchenko submitted:
> 
> >239.192.0.x
> >
> >On Mon, 2006-01-30 at 13:40 -0800, Tim Stevenson wrote:
> > > What group(s) are you sending to?
> > >
> > > Tim
> > >
> > > At 01:28 PM 1/30/2006, Vladimir Ivashchenko murmered:
> > > > > > The problem is that 6500 seems to unconditionally forward
> > all multicast
> > > > > > traffic to all trunk ports even if there are no receivers 
> > > > > > there. E.g. "show mac-address-table multicast" does not show 
> > > > > > any entries for that port, however it still receives all 
> > > > > > multicast traffic.
> > > > > >
> > > > > > Any ideas?
> > > > >
> > > > > The 6500 is going to forward multicast traffic to any routers it
> 
> > > > > learns about. Does a "show multicast router" on the 6500 list 
> > > > > all the trunk ports?
> > > >
> > > >I checked it (using IOS's sh ip igmp snooping mrouter), only one 
> > > >port there as expected.
> > > >
> > > >--
> > > >Best Regards
> > > >Vladimir Ivashchenko
> > > >Chief Technology Officer
> > > >Thunderworx, Cyprus - www.thunderworx.com 
> > > >_______________________________________________
> > > >cisco-nsp mailing list  cisco-nsp at puck.nether.net 
> > > >https://puck.nether.net/mailman/listinfo/cisco-nsp
> > > >archive at http://puck.nether.net/pipermail/cisco-nsp/
> > >
> > >
> > >
> > > Tim Stevenson, tstevens at cisco.com
> > > Routing & Switching CCIE #5561
> > > Technical Marketing Engineer, Catalyst 6500
> > > Cisco Systems, http://www.cisco.com
> > > IP Phone: 408-526-6759
> > > ********************************************************
> > > The contents of this message may be *Cisco Confidential* and are 
> > > intended for the specified recipients only.
> >--
> >Best Regards,
> >Vladimir Ivashchenko
> >Chief Technology Officer
> >Thunderworx Cyprus - www.thunderworx.com
> 
> 
> 
> Tim Stevenson, tstevens at cisco.com
> Routing & Switching CCIE #5561
> Technical Marketing Engineer, Catalyst 6500
> Cisco Systems, http://www.cisco.com
> IP Phone: 408-526-6759
> ********************************************************
> The contents of this message may be *Cisco Confidential*
> and are intended for the specified recipients only.
> _______________________________________________
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-- 
Best Regards,
Vladimir Ivashchenko
Chief Technology Officer
Thunderworx Cyprus - www.thunderworx.com