[f-nsp] Multicast is being switched by LP CPU on MLXe?

[Eldon Koyle]

For IGMP snooping to work, there must be an L3 device acting as an
IGMP querier on your L2 domain (typically a router).  This device is
in charge of keeping track of which IGMP clients have asked for which
multicast groups, and periodically asking if they still want it.  The
MLX would not need to be the querier, but there has to be one in that
VLAN.

If there is no IGMP querier, your only real option would be to flood
all the multicast (unless you are connecting a group of routers that
are speaking PIM, then pim snooping might be able to help you).

-- 
Eldon

On Mon, Dec 19, 2016 at 11:45 AM, Daniel Schmidt <daniel.schmidt at wyo.gov> wrote:
> Doesn't work that way.  You need something to generate the igmp queries - a
> l3 interface.  Without it, igmp snooping doesn't work and you get exactly
> what you have - a broadcast being forwarded out all ports killing the CPU.
>
> On Mon, Dec 19, 2016 at 11:37 AM, Alexander Shikoff <minotaur at crete.org.ua>
> wrote:
>>
>> On Mon, Dec 19, 2016 at 11:20:36AM -0700, Daniel Schmidt wrote:
>> >    It's been a while, but I wouldn't think that pim snooping would not
>> > do a darn thing on l2,
>> >    you would want igmp snooping.  That said, I don't think that would
>> > work without at least a
>> >    local l3 interface to respond to the queries.  Otherwise, you might
>> > as well just use
>> >    broadcast. (Not that I recommend that)
>>
>> Hi!
>>
>> I don't need this box to respond and/or generate IGMP queries.
>> I just need to snoop them in order to prevent unnecessary multicast
>> flooding over all ports in certain VLAN.
>>
>> Again, my configuration is:
>>
>> !
>> vlan 450 name ITCons2DS_test
>>  tagged ethe 7/1 to 7/2 ethe 9/5 ethe 11/2 ethe 12/8 ethe 13/8
>>  multicast passive
>> !
>>
>> That's all. No any L3 multicast routing. Just IGMP snooping.
>>
>> And with such configuration my MLXe-16 starts switching multicast
>> packets by LP CPU.
>>
>> --
>> MINO-RIPE
>
>
>
>
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