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New Member

Need help to deploy IP Multicast in private network

Hi,

I am currently working on a project where there is an urgent requirement to deliver an IP multicast solution.

The network itself is fairly simple.

IP Cameras as connected to pairs of Catalyst 2960 switches in 'access nodes'. There are 8 cameras per node, 4 on each switch. There are multiple nodes, 3 at the moment in our testing environment, all trunked together, so 24 cameras in total.

The Catalyst 2960 switches are trunking to a Core node, which consists of a pair of Catalyst 3750 switches with MHSRP configured for each of 8 VLANs, with 2 DCs and 2 Video storage servers for storing camera footage attached to access ports on those switches. We also have workstations attached to the core node switches which have software installed to view live images and manage the cameras across the network.

We have no routing - the access switches have default gateways pointing to the VLANs SVIs configured on the core switch, and each function has its on VLAN. InterVLAN routing is enabled on the 3750s and connectivity is working fine.

I wish to send a TCP stream to the Video Storage servers for storage, and to multicast to the workstations so that the software can see multiple streams from multiple cameras.

Could someone please suggest a suitable deployment strategy, including how to configure the cameras and switches appropriately to allow this to happen? I am struggling to understand what type of configuration is required.

Much appreciated. I'm actively viewing this thread for assistance.

Everyone's tags (1)
21 REPLIES
Hall of Fame Super Blue

Need help to deploy IP Multicast in private network

Martin

We have no routing - the access switches have default gateways pointing to the VLANs SVIs configured on the core switch, and each function has its on VLAN. InterVLAN routing is enabled on the 3750s and connectivity is working fine.

Can you clarify, you say "we have no routing" and then you say "iner vlan routing is enabled on the 3750s"

Which vlan are the cameras in ?

Which vlan are the storage servers in ?

Which vlan(s) are the workstations in ?

Jon

New Member

Re: Need help to deploy IP Multicast in private network

Jon,

Thanks for responding!

Apologies, I mean we have no routing protocol running on this network, it's all VLANs with 'access vlan xxx' configrued for hosts, and 'ip routing' enabled for inter VLAN routing on the core switches. All nodes are trunking to each other and back to the core node. I have an ACL in place to restrict VLAN 110s access to the other VLANs but it's not part of this setup at the moment.

The cameras are in VLAN 104.

The Storage servers are in VLAN 100.

The workstations are in VLAN 105.

Thanks,

Martin

Hall of Fame Super Blue

Need help to deploy IP Multicast in private network

Martin

Sorry, i should have checked in the last post. What feature set are you running on the 3750s ?

Jon

New Member

Need help to deploy IP Multicast in private network

Hi Jon,

We're running IPBASEk9-M on the 3750s on sw version 12.2(55)SE1.

Thanks,

Martin

Hall of Fame Super Blue

Need help to deploy IP Multicast in private network

Martin

Okay, that means you cannot use multicast routing in terms of PIM because it is not supported in IP Base. There is a feature called PIM stub routing which is supported but i have never used it and haven't even read up on it. So i will have a quick read and see if it could help in your situation.

Jon

New Member

Re: Need help to deploy IP Multicast in private network

Jon,

Thanks for this, I appreciate it.

I can see that the 3750 switch allows me to configure 'ip multicast-routing' as a command in configuration mode, but I did read that there are some limitations.

Thank you,

Martin

Hall of Fame Super Blue

Re: Need help to deploy IP Multicast in private network

Martin

With PIM stub routing the assumption is that you have a L3 port on your 3750s connected to a router/L3 switch that can do multicast routing. But you don't. However i found this thread where a poster says you can configure a loopback interface and configure it as the RP and then announce that. See this thread -

https://supportforums.cisco.com/thread/2153703

the third and fourth posts are the ones you are interested in.

Note also that, as i said, i have never used this feature so i can't guarantee it will work.

Jon

New Member

Need help to deploy IP Multicast in private network

Jon,

Yeah, I've seen example configs elsewhere with loopback interfaces configured, so I'm sure that's an option. However there was no satisfactory explanation to explain how each device should be configured and why, so I can figure out what is needed.

I'm just generally not too clear on what I need to do.

If you could explain how this would operate on my network, and show the configuration, it would really help.

My biggest problem is I can't extrapolate the information available on Cisco tech docs etc and apply those concepts to my network. No recent experience in IP Multicast and not too familiar with the technology.

Martin

Hall of Fame Super Blue

Re: Need help to deploy IP Multicast in private network

edited

Hall of Fame Super Blue

Re: Need help to deploy IP Multicast in private network

Martin

The examples you have seen are probably for when the L3 switch supports full multicast routing but this is not applicable in this case. So -

1) you need to make sure IGMP snooping is enabled on all your switches. It should be enabled by default. There is nothing else to do on the access switches.

2) On the 3750, if you look at the thread i linked to all the config is there ie.

a) from the third post in that thread you configure -

ip mutlicast-routing distriibuted

then under each SVI you need to route multicast between you add "ip pim passive"

b) from the fourth post, you then need to configure a loopback and add the rest of the config in that post.

Whether this will work or not i can't say.

In terms of operation. IGMP snooping is a L2 feature that allows a L2 switch to listen to IGMP responses from clients and then map the port that the client is reachable on to the multicast mac address of the stream. That way only the clients that actually want the stream receive it.

The rest of the config is concerned with routing the multicast stream between vlans.

It's important to understand that virtually all the docs you will have read would be for multicast routing when you can enable full multicast routing on the switch. You can't because of your feature set so the solution above is more of a workaround.

If you need a more general understanding of multicast then perhaps you could ask specific questions and i will try to answer them.

Jon

New Member

Need help to deploy IP Multicast in private network

Hi Jon,

Yes, you're right, this was the problem I was having. I couldn't see how to achieve this solution on my particular network, so needed to know if it was possible by consulting someone with more experience.

I'll havea  look at this just now and come back to you, but I do have one question.

The L3 switches are redundantly operating as default gateways, I've split the active standby routers across both switches as a psuedo load-balancing configuration using MHSRP. How does this affect the location of the multicast configuration? I won't be able to configure the same loopback address on both switches so I'm not sure.

Martin

New Member

Need help to deploy IP Multicast in private network

Hi Jon,

I've just tried to apply the config you suggested in posts 3 and 4, but found that the last two statements are not available for configuration on the 3750s.

ip pim bsr-candidate Loopback0 32 101

ip pim rp-candidate Loopback0 interval 10 priority 101

The only option I have is 'bsr-border' and I cannot configure an rp-candidate.

Thanks,

Martin

Hall of Fame Super Blue

Re: Need help to deploy IP Multicast in private network

Martin

I have just realised another issue with that config. Because PIM is passive it is not making any IGMP queries so there is  nothing for IGMP snooping to listen to. That would mean that within the vlans you have configured for multicast routing, all ports would receive the multicast stream whether they wanted it or not which is not ideal.

Would it be possible to upgrade your license to support full multicast routing ?

As for why these commands are not supported, i don't have an 3750 to test with but that thread was specifically about the 3560/3750 running IP Base. Those commands you can't enter, they are not part of the interface config, they are configured from config mode.

Jon

Hall of Fame Super Blue

Re: Need help to deploy IP Multicast in private network

Martin

Apologies for being rather vague on some of this it's just that i have not configured PIM stub routing before and not been able to test it so i am unable to saty exactly what will happen with this config.

I do think that because no IGMP queries are being made in each vlan then the mutlicast stream may route with the config in that other post but it will still be flooded to all ports in the vlan. Again, without actually being able to test this i cannot say for sure.

You can enable something called the IGMP snooping querier on a per vlan basis and then IGMP queries would be made but i don't know how this will interact with the workaround config in the other thread.

Jon

New Member

Need help to deploy IP Multicast in private network

Hi Jon,

This config is within a test environment which will be replicated dozens of times to other sites, so any upgrades we need to do is multiplied by the number of switches we need to upgrade. I'm pretty sure the cost of those license upgrades will prohibit that so I am hoping to try and find a solution within the limitations of the equipment we have.

I do appreciate your help and I understand it's an awkward setup to work with without IPservices.

Martin

Re: Need help to deploy IP Multicast in private network

Hello Martin/Jon

Reading your posts you seem very restricted in terms of choices provided by Jon, so not sure if this will applicable or not.

You could possibly try enabling igmp snooping of the L2 switches for the sepcifc vlans

ip igmp snooping

ip igmp snooping vlan xx

Then on the L3 switches SVI's apply pim-dense mode -  although these are implict mc messages by dense mode they should reach all host on all vlans and then you may be able to restrict MC Hosts on the various vlans from joining specific MC groups via an acl .

access 1 deny 224.8.8.8

access 1 deny 224.9.9.9

access 1 deny 224.x.x.x etc....

acces 1 permit any

ip multicast-routing distributed

int vlan xxx

ip pim-dence mode

ip igmp access-group 1

What do you think?

res

Paul

Please don't forget to rate any posts that have been helpful.

Thanks.

Please don't forget to rate any posts that have been helpful. Thanks.
Hall of Fame Super Blue

Re: Need help to deploy IP Multicast in private network

Paul

I don't think IP Base supports any PIM mode other than PIM stub routing (unless you know otherwise) so your solution wouldn't work. Or perhaps i am not understanding ?

Martin

I think the only way forward is to test what we have already covered.

I didn't realise this was a test environment so at least you can try all things out without worrying about the production network.

The thread i linked to suggested that you can get the routing working even without a L3 device capable of running full multicast routing but at the moment the question concerns those extra commands you can't enter. Can you verify they are not available in config mode ?

An additional problem is because PIM is passive on the SVIs no IGMP queries are being made so there is no way for the switches to work out which ports needs the multicast stream and so it will be flooded.

There is a function, supported on the 3750s called the IGMP querier function which allows the switch to make IGMP queries per vlan without PIM enabled. We may be able to use this but i have absolutely no idea how it will work with the L3 multicast routing config.

I recommend you try and get multicast routing working first. If you can get to the stgae where you can send a multicast stream from one vlan to another then you should be able to use wireshark to then see each port in the destination vlan receiving the stream (even when you don't want it to).

If you can get to that stage we can then try the IGMP snooping querier to see if we can restrict the stream to only those ports that need to receive it. It may be we can't in which case -

a) you could statically configure the multicast mac address to the relevant ports but this is no scalable and does not allow clients to dynamically join and leave the multicast group

or

b) simply allow the stream to be flooded to all ports within the destination vlan. Not ideal and kind of defeats the purpose of multicast but you may have no choice.

I doubt whether any of this would be supported by Cisco though as i think their position would be to simply upgrade to an IP Services license although in understand this may not be possible for you because of cost.

Jon

Hall of Fame Super Blue

Need help to deploy IP Multicast in private network

Martin

Can you confirm whether or not those commands you could not enter were done in config mode ?

Jon

Hall of Fame Super Blue

Need help to deploy IP Multicast in private network

Martin

I'll do some more reading on this tonight or tomorrow morning but we may just have to try multiple test secnarios to see if we can get it to work.

Jon

New Member

Need help to deploy IP Multicast in private network

Hi guys,

Thanks very much for the information. I've been doing a bit of reading myself and I have also reached out to some other guys, and everyone seems to be of the same opinion - I'll need to upgrade the switch images to IP Services in order to have a multicast configuration.

I'm having another look at this today so I'll let you know my findings.

Martin

Hall of Fame Super Blue

Need help to deploy IP Multicast in private network

Martin

Thanks for getting back to us on this.

If you could upgrade to IP Services it would certainly make your job a lot easier

Jon

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