Re: Multicast Limit on 3550

From: Bob Sinclair (bob@bobsinclair.net)
Date: Mon Oct 10 2005 - 14:21:50 GMT-3


Ashok,

To confirm my understanding; are you saying that when you disable igmp
snooping for a vlan, that the switch still dynamically assigns multicast
addresses to ports based on the reception of IGMP membership reports from
directly attached clients? This is not the behavior I would expect. Could
you post some show commands?

Bob Sinclair
CCIE #10427, CCSI 30427, CISSP
www.netmasterclass.net

  ----- Original Message -----
  From: Ashok M A
  To: bsinclair@netmasterclass.net ; gladston@br.ibm.com ;
ccielab@groupstudy.com
  Sent: Monday, October 10, 2005 12:57 PM
  Subject: RE: Multicast Limit on 3550

  Hi Bob,

  I tried your solution given below and it doesn't seem
  to work:
  ~~~~
  no ip igmp snooping vlan 1
  mac-address-table static 0100.5e40.0101 vlan 1
  interface FastEthernet0/3
  ~~~~

  Looks like even snooping is disabled, mac address is
  learnt at the switch. Correct me if i am wrong.

  Thanks & Regards,

  Ashok M A

  -----Original Message-----
  From: nobody@groupstudy.com
  [mailto:nobody@groupstudy.com] On Behalf Of Bob
  Sinclair
  Sent: Thursday, September 23, 2004 3:32 AM
  To: gladston@br.ibm.com; ccielab@groupstudy.com
  Subject: Re: Multicast Limit on 3550

  Gladston,

  Either of those two scenarios will work. You can
  block the igmp membership reports with igmp filters on
  each disallowed layer 2 interface. If you are using
  routers to simulate the host, do not configure PIM on
  the interface.
  The mroute table on the upstream router should not
  indicate a connected host on that interface.

  You could also disable igmp snooping for the vlan and
  hard-code the multicast mac to the permitted
  interfaces, like so:

  no ip igmp snooping vlan 1
  mac-address-table static 0100.5e40.0101 vlan 1
  interface FastEthernet0/3

  HTH

  Bob Sinclair
  CCIE #10427, CISSP, MCSE
  www.netmasterclass.net

  ----- Original Message -----
  From: <gladston@br.ibm.com>
  To: <ccielab@groupstudy.com>
  Sent: Wednesday, September 22, 2004 2:55 PM
  Subject: Multicast Limit on 3550

> How would you limit just some hosts connected to a
  3550 to receive
> multicast packets destinated to 239.192.1.1?
>
> I am reading "Configuring IGMP Snooping and MVR" but
  could not find a
> specific answer.
>
> An indirectly way seems to be configure IGMP Profile
  on each interface.
>
> Globally disabling IGMP and configuring static MACs
  would work? Or 3550 by
> default forward multicast packets to all ports when
  IGMP is disabled, as
> 5500 when CGMP is disabled?
>

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