Problem with multicast receivers

[kpsudhakar31]

Hi All,

I have a multicast source at one end connected to 3750. Receivers(which can’t send multicast joins) are connected to 3750. These end points are connected like,

Multicast source ------  Cisco 3750 ----- Cisco 7600 -------- Cisco 7600 ----- Cisco 3750 ------- Destination.

There are multiple hosts at the destination connected to Cisco 3750, in a single broadcast domain. Problem here is those hosts can’t send IGMP joins to receive multicast traffic.

Is there anyway, That I can make destination hosts to receive the traffic sent by Multicast source by configuring something in Cisco 7600 or Cisco 3750 devices.

[AMediaFilm]

You can use igmp static-group command on 3750 destination interface to start sending packets even there is no receivers. Then turn off igmp snooping (which will lead to broadcasting multicast packets to all destination broadcast domain ports) or add static ports into igmp snooping table.
 

[kpsudhakar31]

Hi,

Thanks for your reply. Can you kindly elaborate a little more. Also, From which device I need to send IGMP joins. 

[AMediaFilm]

To deliver multicast packets to non-igmp hosts, you need:

1. working multicast routing in segment: "Cisco 3750 ----- Cisco 7600 -------- Cisco 7600 ----- Cisco 3750".

2. instruct destination cisco 3750 to send multicast to destination layer 3 interface by adding "ip igmp static-group..." command to interface configuration.

3. broadcast multicast into layer 2 interfaces with receivers which can't send joins or configure static multicast forwarding to layer 2 receiver's ports. First could be done by disabling igmp snooping: no ip igmp snooping vlan 100. Second could be done by "ip igmp vlan 100 static...".

Example for 2 and 3 from list above:

interface Vlan504
 description broken hosts
 ip address whatever_but_had_to_be_set
 ip pim passive
 ip igmp static-group class-map someGroups

class-map type multicast-flows someGroups
 group 238.210.10.6
 group 238.210.10.7 source 172.29.48.17
 group 238.210.11.6 source 172.27.43.16
 group 238.210.11.7

interface GigabitEthernet1/0/3
 description yet another broken host
 switchport access vlan 504
 switchport mode access
 load-interval 30

ip igmp snooping vlan 504 static 238.210.10.6 int gi1/0/3

and so on for each group/port pair

or

no ip igmp snooping vlan 504

to broadcast multicast packets for any group in vlan504

[kpsudhakar31]

Hi, 

Thanks a lot for detailed explanation!!. I will configure and will update you.

Thanks a lot,

Sudhakar.K.P