[c-nsp] multicast on layer 2

[Tim Stevenson]

No. IGMP snooping *REQUIRES* a querier. Something to send queries. A 
router, or the switch configured as querier. I recommend reading the 
document I linked to.

Tim

At 08:23 AM 6/27/2005, Tantsura, Jeff observed:
>Tim,
>
>So if there were no layer 3 interfaces configured, it would work, right?
>
>Jeff
>
>-----Original Message-----
>From: Tim Stevenson [mailto:tstevens at cisco.com]
>Sent: 27 June 2005 17:14
>To: Tantsura, Jeff; 'Andrew K Ho'
>Cc: cisco-nsp at puck.nether.net
>Subject: RE: [c-nsp] multicast on layer 2
>
>Enabling PIM enables IGMP, and the router starts sending periodic General
>Queries. There is no way to enable queries w/o enabling PIM. But, as long
>as "ip multicast-routing" is not in the config, you won't L3 switch the
>multicast.
>
>The other options are as I described. You need a querier in the VLAN, or
>you need to disable snooping & flood on all ports.
>
>Tim
>
>At 07:14 AM 6/27/2005, Tantsura, Jeff observed:
> >Presence of layer 3 interface on the same VLAN could change the picture.
> >Since sources and receivers would register on it enabling PIM could help.
> >Could you test it with PIM enabled and let me know whether it helped?
> >
> >BTW without IGMP snooping there's no point in using multicast, in fact
> >switch will broadcast every multicast frame.
> >
> >--
> >Jeff Tantsura  CCIE# 11416
> >Senior IP Network Engineer
> >
> >
> >-----Original Message-----
> >From: Andrew K Ho [mailto:aho at yorku.ca]
> >Sent: 27 June 2005 15:28
> >To: Tim Stevenson
> >Cc: cisco-nsp at puck.nether.net
> >Subject: Re: [c-nsp] multicast on layer 2
> >
> >I'm afraid this setup is just on layer 2.  Two directly connected switches
> >on trunk links, both allowing the same vlan.  Although there is a vlan
> >interface on the router, the traffic shouldn't be processed by the router.
> >  Hence no need for PIM (as Jeff pointed out).  For reasons I can't fathom,
> >IGMP snooping is always off on our network, and as our planners want it to
> >remain this way, the IGMP querier feature would not make any difference.
> >
> >Thx for all the replies.
> >
> >Andy
> >
> >
> >
> >Tim Stevenson <tstevens at cisco.com>
> >06/24/2005 03:57 PM
> >
> >To
> >Andrew K Ho <aho at yorku.ca>, cisco-nsp at puck.nether.net
> >cc
> >
> >Subject
> >Re: [c-nsp] multicast on layer 2
> >
> >
> >
> >
> >
> >
> >You might try:
> >* enabling PIM on an SVI in that VLAN
> >* enabling the IGMP querier feature
> >* disabling IGMP snooping (not really advisable, floods to all ports)
> >
> >For IGMP snooping to work properly, an IGMP querier MUST be present in the
> >
> >VLAN.
> >
> >See:
> >http://www.cisco.com/warp/public/473/38.html
> >
> >HTH,
> >Tim
> >
> >At 12:28 PM 6/24/2005, Andrew K Ho declared:
> > >Hi, I was hoping someone could help me on this.
> > >
> > >I'm having a problem with an application on our network called Drive
> >Image
> > >Pro (used to push pc images to build client machines), which purports to
> > >be a multicast application, but which is only being used at layer 2 as
> >all
> > >traffic btn server and client  is contained in 1 vlan, hence is working
> > >essentially the same as broadcasts.  Howevever, the server and client
> >send
> > >multicast packets to a multicast address to send packets.
> > >
> > >The server is connected to  Model / Serial cisco WS-C6509  OS / Version
> > >ios / 12.1(22)E2 on a 100m connection and the client is connected to a
> > >100m port on  Model / Serial cisco 4506  OS / Version ios / 12.2(20)EW .
> > >They are connected directly through a trunk link, running at gig on
> >fiber.
> > >  The server and  client are pingable from either side so there is no
> > >reachability issue.
> > >
> > >If the server and client are both on the 4506, it works fine, but won't
> > >work if connected as described above.  There are no configs affecting
> > >multicast packets.
> > >
> > >Has anyone come across a problem like this or have any clue as to why it
> > >may not be working?
> > >
> > >Thx in advance
> > >
> > >Andy
> > >_______________________________________________
> > >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.
> >
> >_______________________________________________
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>
>
>
>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.



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.