[c-nsp] igmp snooping inside 802.1q trunks

[Vladimir Ivashchenko]

Thanks for your help. We shall try our luck with TAC.

On Wed, 2006-02-01 at 15:57 -0800, Tim Stevenson wrote:
> Not sure what to conclude based on that information.
> 
> Flooding will happen in a few cases that occur to me:
> * IGMP snooping disabled
> * the port is learned/configured as a mrouter port
> * no querier present in the vlan (you can get unpredictable behavior 
> here, snooping is not supported unless there is a querier)
> * the group IP maps to a reserved range MAC (0100.5e00.00xx)
> * a new source starts sending & no group mac exists (need to install 
> a "source-only" entry - this flooding lasts a very short time)
> * a source-only entry is removed from the h/w but the source is still 
> sending (again, flooding for a very short time)
> 
> The fact that the streams originate from any particular switch (with 
> or without the querier attached) should not make any difference that 
> I can think of unless it falls into the above categories.
> 
> A TAC case is probably the quickest way to resolution here...
> 
> Tim
> 
> At 11:02 AM 2/1/2006, Vladimir Ivashchenko submitted:
> 
> >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.
> > > _______________________________________________
> > > 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/
> >--
> >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.
-- 
Best Regards,
Vladimir Ivashchenko
Chief Technology Officer
Thunderworx Cyprus - www.thunderworx.com