From: Joel W. Ekis (jekis@xxxxxxxxx)
Date: Tue May 02 2000 - 22:34:40 GMT-3
Two different issues: The MSFC can act as the router for a C5k that needs CGMP
support. The C6k has ASICs that do wire-rate IGMP Snooping and don't need the
support of a router.
To sum up - the C6k switch cannot use a CGMP enabling router. The MSFC can be
a
CGMP enabling router for another switch like the C5k.
The other routers connecting to the C6k and the MSFCs all need PIM. Preferably
in sparse or sparse-dense mode. Using dense mode is fine in the lab, but is
really, really bad in a production environment.
That help?
Joel
Also, the Multicast book by Beau Williamson is excellent. I highly recommend
it for all Multicast studying.
At 06:19 PM 5/2/2000 -0400, John Conzone wrote:
> Okay. Well it just so happens that the design calls for a 6509 with a
>MFSC as the core connected to multiple 5500's. So are you saying that the
>Virtual interfaces on the 6500 that I'll use to route between VLAN's don't
>support CGMP? How will it communciate mutlicast control info with the
>5500's? Also, do I ned to enable anything on the other routers connected to
>the 6500?
>
>----- Original Message -----
>From: "Joel W. Ekis" <jekis@cisco.com>
>To: "John Conzone" <jkconzone@home.com> "ccielab" <ccielab@groupstudy.com>
>Sent: Monday, May 01, 2000 9:12 PM
>Subject: Re: controlling multicasts in a switched environment
>
>
>> PIM is used for L3 routing control purposes. To help the switch
>understand
>> which ports need a specific multicast stream use the following interface
>> command 'ip cgmp'. It would be unlikely that you would use CGMP and not
>use
>> PIM. You can use PIM without CGMP, especially on the C6k - it only does
>IGMP
>> Snooping.
>>
>> PIM stands for Protocol-Independent Multicast, it uses any route in the
>routing
>> table, routing protocol origin is immaterial. IGMP is a group management
>> protocol, not a routing protocol.
>>
>> Joel
>>
>> Try having a Pale Ale (I prefer Boulevard - local KC beer); great for
>> un-freezing brains. ;-)
>>
>> At 07:44 PM 5/1/2000 -0400, John Conzone wrote:
>> >
>> > I've been exploring multicast control using CGMP on Catalyst
>switches. I
>> > see that CGMP is on by default, and creates lists of hosts who have
>joined
>> > multicast groups and forwards multicast packets only out ports to those
>> > hosts. The fast leave feature decreases the time it akes for a host top
>be
>> > deleted from a group, or is it the time it akes to delet a group.
>> > Anyway, my real question is that all the documentation states that
>this
>> > must work in conjunction with a router enabled with CGMP. Does this mean
>a
>> > router with PIM enabled on its interfaces? I'm a little confused. I
>thought
>> > PIM used IGMP.
>> > Or can you enable CGMP on routers without PIM. OR does PIM invoke both?
>> > AHHHHHHHHHHHHH!!!!! Cisco brain freeze!
>>
>>
>>
>
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