On 10/13/2010 08:37 AM, Gert Doering wrote:
Hi,
On Wed, Oct 13, 2010 at 08:18:47AM +0100, Phil Mayers wrote:
On 10/12/2010 09:46 PM, Gert Doering wrote:
On Tue, Oct 12, 2010 at 02:59:28PM -0500, [email protected]
wrote:
The switch listens to the following messages in order to detect router
ports with IGMP snooping:
· IGMP Membership query send to 01?00?5e?00?00?01
· PIMv1 hello send to 01?00?5e?00?00?02
· PIMv2 hello send to 01?00?5e?00?00?0d
· DVMRP probes send to 01?00?5e?00?04
· MOSPF message send to 01?00?5e?00?05 or 06
Thanks for clarifying this. Indeed, with this information, IGMP snooping
should never be harmful for router-switch-router traffic.
That is not my experience.
Can you share details?
Sorry, I did realise after sending that it was too terse to be useful.
Essentially I've observed exactly the behaviour you described in a
previous email. Two PIM routers either side of a layer2 switch would
fail to pass any routed multicast traffic because IGMP snooping was
enabled and was "eating" it. PIM snooping was the solution I decided I
needed, but it was easier to just remove the switch and go for a direct
link in that case.
Now I must admit: when I think about it, I don't know what model the
layer2 switch in question was; it may not even have been a Cisco (this
was some time back) in which case Christopher may also be right ;o)
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