Multicast mac address table empty.

[Waldo Roca Martin]

Hi

One costumer  reported us a issue with the multicast traffic. The problem is when they enable igmp snooping the multicast trafic stop to work. He said the problem happened suddenly without any change configuration. 

The connectios are these.

core switch ---> port channel 3 ---> access switch ----> gi 0/42-----> client

access switch ----> port channel 1 ---->core switch.

IP multicast traffic 239.228.41.23

VLAN ID: 227

The Core uses pim sparse mode and the RP is its loopback interface.

Core routes multicast correctly to vlan

(*, 239.228.41.23), 1d23h/00:02:45, RP 172.16.100.25, flags: SJC

   Incoming interface: Null, RPF nbr 0.0.0.0

   Outgoing interface list:

     Vlan227, Forward/Sparse, 1d23h/00:02:45

Core routes multicast in L2 to Port channel 3.

core#show mac address-table multicast vlan 227 igmp-snooping

  vlan   mac address     type   learn qos             ports

-----+---------------+--------+-----+---+-------------------------------

-----+---------------+--------+-----+---+-

  227  0100.5e64.2917    static  Yes          -   Router,Po3,Po29

Switch Access has igmp snooping enable.

switch#sh ip igmp snooping vlan 227 Global IGMP Snooping configuration:

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

IGMP snooping               : Enabled

IGMPv3 snooping (minimal)   : Enabled

Report suppression           : Enabled

TCN solicit query           : Disabled

TCN flood query count       : 2

Robustness variable         : 2

Last member query count     : 2

Last member query interval   : 1000

Vlan 227:

--------

IGMP snooping                       : Enabled

IGMPv2 immediate leave             : Disabled

Multicast router learning mode     : pim-dvmrp

CGMP interoperability mode         : IGMP_ONLY

Robustness variable                 : 2

Last member query count             : 2

Last member query interval         : 1000

Swtich access detects the igmp trafic and asosciates the ports to the groups properly.

switch#sh ip igmp snooping groups

Vlan      Group                    Type        Version     Port List

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

227       239.228.41.23            igmp        v2          Gi0/42, Po1

Switch access has mroute port

switch#sh ip igmp snooping mrouter

Vlan   ports

----   -----

227   Po1(dynamic)

But mac address table multicast in switch access is empty.

swtich#show mac address-table multicast vlan 227

Vlan   Mac Address       Type       Ports

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

May be this is the cause of the problem.

But. I don't know why the switch is not filling in the mac table if it konws all information.

Any idea?

Thank you.

Best regards.

[Waldo Roca Martin]

We have introduced manually the address to the mac address table. Example

mac-address-table static 0100.5e64.2917 vlan 227 interface gi 0/42 po 1

Vlan    Mac Address       Type        Ports

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

227    0100.5e64.2917    USER        Gi0/42 Po1

No work neither.

[paul driver]

Hello Waldo

Usually igmp is enabled by default on most cisco devices so where have you enabled snooping? (version3)

Also I can see DVMRP learning, so was snooping enabled on a non cisco M/C device?

res

Paul

Please don't forget to rate any posts that have been helpful.

Thanks.

[Waldo Roca Martin]

Hello PDriver

Usually igmp is enabled by default on most cisco devices so where have you enabled snooping? (version3)
Also I can see DVMRP learning, so was snooping enabled on a non cisco M/C device?

On the core and access switch.

If I disable igmp snooping, everything work fine.

But I don't undertand why if the access switch asociate the port 0/42 (where the client is connected) to the correct multicast group and multicast flow doesn't reach this port.

The costumer wants igmp enable, and he said everything worked and suddenly stoped to work.

Both devices are Cisco.

Thank you.

Best Regards

[paul driver]

Hello

For sparse mode? (static/auto/bsr/anycast)

If its just between these two devices then staitc RP would be fine - using ip pim rp-address

and of course have a routed path to the RP or in your case the loopback on the core.

res

Paul

Please don't forget to rate any posts that have been helpful.

Thanks.

[Waldo Roca Martin]

Hi

Yes is static sparse mode with rp-address interface loopback on the core.

But I didn't check the conectivity between the client vlan to that interface loopback. I will.

Edit: Yes threre is ping from the client/switch and the RP point.

We goona try to reload the access switches (may be we should've done this at the begining )

I will update the information.

Thank you