igmpv3 snooping in catalyst 4900M L2 only Switch

[Carlos T]

Hi.

Scenario:

Host-A ----------- CATALYST 4900M -------------- Host-B

Host A is the source of multicast traffic for group 239.50.50.50 and Host B is the receiver. Both are using IGMPv3.

Host A and Host B belong to the vlan 701 configured in the catalyst 4900M. There is no svi for vlan 701, it is only configured as L2.

The catalyst 4900M is configured as a pure L2 switch with igmpv3 snooping enabled by default. As there is no router here, there is no mrouted port nor pim enabled.

Host B can succesfully receive the stream of multicast data sent from source host A. The issue we have is that at the catalyst 4900M we can not see the multicast mac address table, or the igmp snooping group state. Just want to know what ports are receiving traffic destined to which multicast mac address groups. Just want to stay sure, there is no flooding here. Any clue about how to look at that info?

Paste some outputs:

4900A#show ip igmp snooping vlan 701
Global IGMP Snooping configuration:
-----------------------------------
IGMP snooping              : Enabled
IGMPv3 snooping            : Enabled
Report suppression         : Enabled
TCN solicit query          : Disabled
TCN flood query count      : 2
Last Member Query Interval : 1000

Vlan 701:
--------
IGMP snooping                       : Enabled
IGMPv2 immediate leave              : Disabled
Explicit host tracking              : Enabled
Multicast router learning mode      : pim-dvmrp
Last Member Query Interval          : 1000
CGMP interoperability mode          : IGMP_ONLY
4900A#

4900A#show mac address-table multicast

No entries present.

4900A#show ver

Cisco IOS Software, Catalyst 4500 L3 Switch Software (cat4500e-IPBASEK9-M), Version 12.2(53)SG4,

Thanks,

Carlos Trujillo.

[Carlos T]

Forgot the last output that is showing nothing:

4900A#show ip igmp snooping groups

Vlan      Group             Version     Port List

------------------------------------------------------------

4900A#

[Jon Marshall]

Carlos

If you are not using PIM then you need to configure the IGMP snooping querier function otherwise multicast traffic will be sent to all ports. See this very recent thread for a full explanation -

https://supportforums.cisco.com/thread/2110469?tstart=0

Also here is the 4900 config for the IGMP querier -

http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/53SG/configuration/multi.html#wp1163784

Jon

[Carlos T]

Thanks John for your answer.

Tried to enable  without succesfull results, Could it be related the version of the querier available is 1-2, even when Im using igmpv3? Seems there is no version 3 querier. Also there appears a message once I enable the querier command.

4900A(config)#ip igmp snooping querier version ?

  <1-2>  IGMP version

4900A(config)#ip igmp snooping querier        

IGMP Querier function cannot be operationally enabled on some VLANs because the required conditions have not been met.

4900A(config)#^Z

4900A#

4900A#show ip igmp snooping querier

Vlan      IP Address        IGMP Version   Port               

----------------------------------------------------------------

700       192.168.19.25     v2             Gi3/19                  

701       192.168.19.6      v2             Switch       

4900A#show mac address-table multicast

No entries present.

[Jon Marshall]

Carlos

The docs say that the querier can send out a v3 query.

Can you post output of "sh ip igmp snooping membership vlan 701"

Jon

[Carlos T]

It does show nothing.

4900A#show ip igmp snooping membership vlan 701

4900A#show ip igmp snooping mrouter

Vlan    ports

----    -----

700    Switch

701    Switch

4900A#show ip igmp snooping mrouter vlan 701

Vlan    ports

----    -----

701    Switch

[Jon Marshall]

Is the mutlicast stream actually running now ?

Jon

[Carlos T]

Appreciate your help Jon,

Unfortunately the lab was made 2 hours ago, Right now, Im checking the logs, to figure out what happened.

As the lab is at customer site, let me double check that tomorrow, and be completely sure to type that "show" commands  once the streams are flowing.

Thanks,

Carlos Trujillo.

[Jon Marshall]

Carlos

No problem.  It might we worth doing a 2 step process ie.

1) don't configure querier, start the multicast stream and then for one of the ports that shouldn't receive the multicast traffic span it and use wireshark to see if it is receiving the traffic.

2) then configure IGMP querier and do the same and see what happens.

I have used the IGMP querier before and it works are expected but i have never used it with v3. The docs suggest though that it is still neeed if you have not enabled PIM on an interface.

Jon