Multicast routing with IP Base Image

[l.buschi]

Hello,

I have a network composed by two building. Each building has its own distribution layer realized with 3850 IP Base Catalyst.

The two building are layer 3 connected.

How can I route multicast traffic without IP service licenze on 3850?

Tks Johnny

[Joseph W. Doherty]

Where do you route unicast?

[l.buschi]

All unicast routing is done by each catalyst 3850 (distribution switches) with ip base license.

[Joseph W. Doherty]

Then you might have a problem w/o the IP Services license.

[roor · Accepted solution]

Hi ,

Complete multicast routing is supported with the ipservices license on 3850 . IPBase supports PIM stub. Please see the link below for details:

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/software/release/3se/multicast/configuration_guide/b_mc_3se_3850_cg/b_mc_3se_3850_cg_chapter_0111.html#reference_1B9A754AFA654F01A8DEF269EEEBBAF9

HTH,

Roopa

[l.buschi]

So if I have my multicast servers behind an IP service router, all my buildings with IP Base router can use PIM stub to route multicast?

Thank you very much for your help

[Joseph W. Doherty]

I haven't used PIM stub, and hopefully Roopa will also respond, by I would suspect PIM stub would only work for you if you have another full feature router "above" your 3850s.  I.e. if your 3850s directly connect, I suspect it won't help w/o upgrading their feature licenses.

On the otherhand, your OP did mention the 3850s were at your distribution layer.  If your 3850's route indirectly through some core layer that interconnects your site, you might be able to work that with PIM stub.

Again, though, not being familar with the feature, I wonder if it is meant to complement the unicast stub routing feature.

[Jon Marshall]

Joe rightly says it is meant to compliment the unicast stub routing issue and looking at the 3850 configuration guide it says you must use unicast stub routing to use it.

This is slightly different than the 3650/3750 guide where it says you should use it but you could actually configure static multicast routes to bypass it and so there may have been a workaround.

Not being able to test it I can't say.

The PIM stub feature basically says you can only use PIM in passive mode on your SVIs because there is an assumption that there will be no PIM neighbors in those vlans.

So your 3850s should not be transit devices for multicast traffic ie. multicast traffic should not be routed to a 3850 and then on to another L3 device.

But you can configure full PIM on L3 routed ports.

The idea is as Joe again points out that you connect your 3850s to a L3 device running full PIM and then multicast traffic can be routed to and from the 3850s.

Because your 3850s are directly connected using L3 routed ports by the sounds of it I did think you may be able to run full PIM on those and then you could route between the two and with the 3650/3750s this may have worked because as I said above the docs only said you should run unicast stub routing not that you had to.

However the 3850 docs do seem more definitive in saying you have to run it.

Jon

[MikeJLove]

Are there any multicast design guides around anymore?