IGMP Join Group

[dawitassefa]

Hell there,

   I have multiple (like more than 100) IP igmp join-group statements for multiple multicast groups in a single interface. Is there any way to summarize all these multiple igmp join-group statements in one join-group satement. I was planning to use ip igmp access-group with an access-list. But igmp access-group is for filtering a multicast group and it's not a joining group. Any help is appreciated!

Thanks,

[John Blakley]

Not that I'm aware of. If you were to summarize, the router would think that you'd want to join the summarized group instead of the individual groups that you're needing. Do you have these joins on the router's interface?

HTH,

John

[dawitassefa]

Yes, I configured the joined statement on the CE router as it is connected to MPLS cloud,. My plan was to create like a standard access-list that permit all the multiple multicast groups and create a single igmp-join group on the router's interface and bind it with that standard access-list. but still no hope....I don't want to use summarization as you said the router might attempt to join that specific summarized group rather than those specific groups....weired!

[Marcel Zehnder]

Hi

Why do you configure join statements at all? Do you really need them? Why don't you just enable PIM (or IGMP if there are no other PIM Routers connected) on your interface and let the clients send the IGMP-Joins?

Regards

[John Blakley]

I agree with Marcel. You usually let the client send the igmp join, otherwise it ends up being an administrative nightmare. On top of that, your interface will always join a group that clients on that segment may not need.

[turbo_engine26]

Hi,

The "ip igmp join-group" command is actually used to make the router itself to join the group as a group member. This command is totally used as a testing method if you don't have group members yet. If, for some reason, a host can't send IGMP Group Membership Report (could be a BUG!) in response to the router's General Query, this command makes the router to join the group and send (S,G) or (*,G) joins to its upstream neighbors to maintain the paths for the group until the host's BUG get fixed. Another case, this command is sometimes used as a debugging method, to make the router reply to the group Ping. For instance, when the router joins the group, you can ping the group and makes the router reply. (Since it is a member)

Therefore, you do not need this command to force the host to join the group. As mentioned by the above users, the host will join automatically (depending on the settings in the multicast application itself).

Hope this helps.

HTH

AM

[mlund]

Hi

If the goal is to put traffic out of an interface without sending it to the cpu, then "ip igmp static-group" is a better choice than "join-group". And for static-group command, you can use a class-map to summarize groups. This example will join 51 groups.

class-map type multicast-flows TEST

group 239.100.100.1 to 239.100.100.30

group 239.100.100.50

group 239.100.100.61 to 239.100.100.80

interface gig1/1

ip igmp static-group class-map TEST

/Mikael

[dawitassefa]

Thank you Guys. The reason I put the join-group on the router interface was the reciever was not sending IGMP join-group properly. Now the reciever is sending joing-group properly and took out all IGMP join-group confs from the router interface and it works.......Once again thank you all for your comments!

[turbo_engine26]

Hi,

Glad to hear your issue got fixed. Please don't forget to rate if any of the above answers helped in fixing your issue.

Regards,

AM