multicast and igmp access group question

dan_track · ‎09-02-2009

Hi,

I have a point-to-point WAN connection connecting site1 to site2. I want to allow multicasts to go from site1 to site2, but want to control what multicast travels down the WAN. My question is will an igmp access group do this for me?

Please see my example config's below:

Site1:

interface GigabitEthernet1/4

ip address 10.25.20.9 255.255.255.252

ip pim sparse-mode

ip igmp access-group wan-igmp

exit

ip access-list standard wan-igmp

permit 233.119.160.128 0.0.0.127

exit

Site2:

interface GigabitEthernet1/20

ip address 10.25.20.10 255.255.255.252

ip pim sparse-mode

ip igmp access-group wan-igmp

exit

ip access-list standard wan-igmp

permit 233.119.160.128 0.0.0.127

exit

Edison Ortiz · ‎09-02-2009

IGMP ACLs restricts hosts not Multicast groups. You need the command IP Multicast Boundary

http://www.cisco.com/en/US/docs/ios/ipmulti/command/reference/imc_03.html#wp1029655

HTH,

__

Edison

dan_track · ‎09-03-2009

Hi

Thanks for that. What does it mean by IGMP ACL's retrict hosts? Can you please give me an example.

Thanks

Dan

Giuseppe Larosa · ‎09-03-2009

Hello Dan,

if having ip pim sparse-dense mode on the interfaces traffic for a group not associated to a RP is treated as dense mode and uses a "flood and prune" strategy: it is sent before an explicit join is done.

the ip igmp join-group command using an ACL filters igmp joins from end user PCs so it can limit what sparse mode groups can travel on the link.

Edit:

I see that you have ip pim sparse-mode so your setup should be effective.

Hope to help

Giuseppe