Posted on June 20, 2019 7:53 pm
 |  Asked by Emiel Raaijmakers
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We currently have a querier (v3) running on VLAN 400 and it perfectly works for multicast group joins within that VLAN. However when performing a source specific group join it seems to forward traffic from other sources as well.

My transmitting part is sending on group with source address
My receiving part is subscribed to group with source address

There is not multicast traffic to group from source; Expected result is that no multicast packets would be received, but it receives all traffic from What configuration is required to enable source specific multicast on the same VLAN?

arista(config)#show ip igmp snooping querier detail
Vlan IP Address Version Port
400 v3 Switch

arista(config)#show ip igmp snooping querier membership
Vlan: 400 Elected: QQI: 5 QRV: 2 QRI: 5 GMI: 15

Groups Mode Ver Num of Sources
————————————————————————- EX v2 0 [] IN v3 1 [ ] EX v2 0 [] EX v2 0 [] EX v2 0 [] EX v2 0 [] EX v2 0 [] EX v2 0 []

arista(config)#show ip mfib
Activity poll time: 60 seconds
Vlan400 (iif)
Activity 0:01:54 ago
Vlan400 (iif)
Activity 0:00:15 ago

Posted by Alexis Dacquay
Answered on August 16, 2020 6:01 am

Hi Emiel,

If you are on a very very old software (e.g. before 4.14 from ~2014), then it would not work.

Can you please share your pim and general multicast configuration?

sh run section pim

sh run section multicast

You can find the PIM SSM range command here:

Extract, in case the link changes:

switch(config)#ip access-list standard LIST_1
switch(config)#router pim sparse-mode
switch(config-router-pim-sparse-ipv4)#ssm range LIST_1

Here are two articles related to PIM SSM:

Some colleague have tested this in lab and it work fine as expected.

They have the following config:

router pim sparse-mode
   ip pim ssm range standard

Then we try to send a IGMPv2 report from the receiver towards the mrouter:


arista...09:31:59(config)#sh ip mroute             Note: no mroute is formed

Then, we send a leave for IGMPv2 and send a new IGMPv3 report and S,G is formed:


arista...09:32:00(config)#sh ip mroute, 0:00:03, flags: JED
    Incoming interface: Null
    Outgoing interface list:

We also tested other groups like and for SSM and  mroute (S,G) for all of them are formed as expected.

After the source starts sending the traffic:, 0:08:44, flags: S
    Incoming interface: Ethernet2
    RPF route: [U] [110/20] via
    Outgoing interface list:
      Vlan110, 0:02:33, flags: S
    Incoming interface: Ethernet1
    RPF route: [U] [110/20] via
    Outgoing interface list:



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