Multicasting... not working across sites

[cpals]

Okay, so I have a LARGE project I'm trying to figure out and no matter how much I search through Cisco's sites I can't seem to find just the right answer that seems to work.

Equipment we're using:

Cisco 6509s at all main sites (4 sites total)
Cisco 3750s for switches inside sites

Network Layout

Site 1 is sort of the hub of all connectivity and Sites 2,3,4 all connect back to it (6509s). Each site has it's own VLAN and are also running 3des encryption on the lines back to Site 1. Also, something that I did not setup but how it is, is that sites 3 & 4 are using VLAN 1 for it's data VLAN so we cannot trunk that VLAN. Currently the cameras are on the same VLAN the data side of the site is on. Site 1 is a little more confusing as it has a VLAN for each IDF, so 4 in total, which are running off 3750s.

The Problem

We're in the process of trying to get 200+ cameras moved over to IP and to stream them via multicast. I can get the multicasting to work inside each VLAN fine with just using the ip multicast-routing and ip pim dense-mode commands on the specific data VLAN at each site.

I can't however view from Site 1 a camera that is setup at Site 2-4. If I do a sh ip mroute I do not see traffic from the other sites.

Questions

1 - I'm not sure I should use dense-mode or not, but it seems to be more of a resource hog. Although, it seems that if you use sparse mode you have to setup more stuff on the routers for it to work though.

2 - I tried trunking a brand new VLAN between all sites to maybe put all of the cameras in their own VLAN, but that didn't seem to work... I must have did something wrong because the CPU usage at our main site went from 2% - 30% !!! Is this a bad way to do it?

3 - Since we use encryption, the actual VLANS that are trunking across sites are different (ie, Site 1 doesn't know about VLAN 1, but does know about VLAN 55, etc). I'm not sure if I need to put ip pim on these VLANs or only the ones that the cameras are specifically on.

4 - I've tried doing the ip mroute command, but not sure exactly the syntax or proper way to set it up. It did not seem to make a difference on anything when I did it.

So what's the best way to do this (mroute or trunking the vlan) and any idea why it's not working? I'm at the end of my rope now...

Thanks!

 

[spidey07]

The best way is you are going to have to take a serious look at design. Multicast routing is not something you just want to turn on - it can have processor implications as well as showing things you weren't really aware of. Oh, and dense mode is evil - avoid at all costs. This is where you need to call in some help - be it from cisco or a consultant.

 

[cpals]

Yeah, we have Embarq looking at it (our vendor), but I like learning on my own and would be impressive to my boss if I figured it out myself. They're giving us a very long ETA of 2-3 months to implement and my boss is in a hurry.

 

[spidey07]

Well be careful, if you want to learn there is a whole book on multicast by ciscopress which would be helpful. There is a real possibility of crashing the whole thing if you don't configure it properly. There should be some good documentation on running PIM and putting the corresponding interfaces in sparse mode. You'll need to setup at least one rendezvous point. That should get the actual mcast routing going. Also make absolutely certain that IGMP snooping is enabled on ALL switches, you run the risk of flooding all that video traffic to every port.

I'll just reiterate that this is something that should be designed from the ground up understanding all the implications and then implemented.

 

[cpals]

Thanks... as usual, very helpful. I'll probably just end up letting them do it. I'm still new to Cisco, but learning mostly on my own. In August I am scheduled to get my CCENT and then I believe after that I just have to take the second test to get my CCNA.