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New Member

Multicast Ports are not Registering

Gentlemen,

In order to prevent flooding, I am trying to figure it out why Multicast mac address are not getting registered in our Catalyst 4500 L3 Switch, I am pretty much sure some configuration are not complete or missing but not sure how to troubleshoot,

Below are enabled and configured.

ip multicast routing

ip multicast auto-enable

ip igmp profile

ip igmp snooping querier

ip pim sparse-dense-mode

Any help/recommendation would be highly appreciated.

By the way, can I just configure a mac access-group and VLAN access-map to block or restrict mac address to go to particular interfaces/vlans?

Regards

Edward

Everyone's tags (3)
2 ACCEPTED SOLUTIONS

Accepted Solutions
Cisco Employee

Multicast Ports are not Registering

Hello Edward,

Not exactly sure what you mean by base IP address. Within your multicast topology - you select single (or multiple in some cases) router to be RP. Then you configure every router within your network with "ip pim rp ADDR" where ADDR is the ip address of the router you selected as RP. That address usually is loopback address not to depend on any link failures as loopback is always UP, but you can also select any other ip within your router to be RP ADDR.

Nik

Cisco Employee

Multicast Ports are not Registering

BTW

If you don't want to have RP configured - you can just change your PIM mode to dense "ip pim dense". This will push multicast to all receivers down from Mcast source and you will not need any RP.

Nik

12 REPLIES
Cisco Employee

Multicast Ports are not Registering

Hi Edward,

Need to do few basic checks in the begining:

- As 4500 configured with PIM - it is a multicast router. Why did you configure igmp snooping querier on it? It should send IGMP queriers without that. Can you check "sh ip igmp int X" where X is interface configured for PIM to see if that is selected as querier

- Can you also check show ip igmp groups interface-name command to check the 4500 to see if it received a join membership.

- As I see you configured 4500 for PIM sparse-dense mode - did it register with RP for those groups? Check "show ip mroute", "show ip mroute count"

Nik

New Member

Multicast Ports are not Registering

Hi Nik,

Thanks for your email and provided great points,

Actually I have not configured the switch and I am just trying to understand the correct configuration and then make the necessary changes,

I am not sure why igmp snooping querier is configured but I can get rid of it for sure, at this point I really don’t like to make any changes to current configuration until I find a good solution so I just created a different vlan (i.e. VLAN 4)and add some printers and netgear switches to have a testing environment and I would like to configure a sparse mode with a single static RP if I am correct just for testing ,

Please let me know what would the best configuration to apply and proceed.

Going back to your questions, I ran Show ip igmp groups and yes there are IGMP connected Group membership and we have got mroute configured on an gig. interface but RP are 0.0.0.0 so I think there is no RP configured for destination.

I really appreciate for your help.

Regards

Edward

Cisco Employee

Multicast Ports are not Registering

You can use "ip pim rp-address ADDR" on all multicast routers to configure RP statically.

nik

New Member

Multicast Ports are not Registering

Thanks Nik,

So regarding the rpaddress, i have to go with the base IP address per rounter , am i correct?

Regards

Edward

Cisco Employee

Multicast Ports are not Registering

Hello Edward,

Not exactly sure what you mean by base IP address. Within your multicast topology - you select single (or multiple in some cases) router to be RP. Then you configure every router within your network with "ip pim rp ADDR" where ADDR is the ip address of the router you selected as RP. That address usually is loopback address not to depend on any link failures as loopback is always UP, but you can also select any other ip within your router to be RP ADDR.

Nik

Cisco Employee

Multicast Ports are not Registering

BTW

If you don't want to have RP configured - you can just change your PIM mode to dense "ip pim dense". This will push multicast to all receivers down from Mcast source and you will not need any RP.

Nik

New Member

Multicast Ports are not Registering

Thanks Nik,

I have deployed ip pim sparse dense mode on a dummy vlan (Vlan 4) and skip configuring RP plus I disable ip igmp snooping globaly and got rid of ip igmp profile too but when I ran show mac address-table on vlan 4, I can see lots of unicast entries and one Multicast Entries with mac address ffff.fff.ffff........and nothing else..., am i missing anything here?

Do I need to configure ip pim sparse dense mode on all interfaces> would it be possible just to test it on a Dummy vlan or an interface and then reconfigure it for the rest?

Regards

Edward

Cisco Employee

Multicast Ports are not Registering

Edward,

Can you just quickly explain how your multicast is flowing - what are the groups used and what are the devices involved between Mcast source and receivers. With Dense mode your source will push the mcast to the connected router configured with PIM dense mode. It will push this tream down to all neighbors configured with PIM dense mode as they will need to build PIM neigborship first. Mcast MAC will be always destination MAC - and it can only be learnt on the switch which does not have PIM configured and rely on IGMP snooping.

If we have PIM - we don't need IGMP snooping as the last router will send queries to hosts. If you have non-PIM switch connected to hosts then it will try to intercept those queries from routers and see which hosts and on which ports need the Mcast stream. Then it will learn the MCAST MAC on those ports.

PIM router wont learn it as PIM router only need L3 info to send traffic out of it towards end hosts.

So there few details so better to start with your design and see what we can do better.

Nik

New Member

Multicast Ports are not Registering

Hi Nik,

Thanks for great details,

I will get back to you after I get more details about its current configuration.

Regards

Edward

New Member

Multicast Ports are not Registering

Hi Nik,

Hope below will shed some light to your questions.

Senders would be Workstations /Servers.

Receivers would be Netgear switch and the main Cisco switch.

FYI. Workstation is connected to Netgear switch and mac address is registered to one of its ports and it forwards it.

Thanks.

Regards

Edward

Gold

Multicast Ports are not Registering

Hi Edward,

rp-address must be a unicast address, same for a multicast group, same on all routers. you can have different RP addresses for different multicast groups though (have to use access lists to define them).

Hope it Helps,

Soroush.

Hope it Helps!

Soroush.
New Member

Multicast Ports are not Registering

Hi Soroush,

 

Thanks for your input,

I am looking through its current configuration to get some idea as to how it’s been configured and setup.

Regards

Edward

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