Any special multicast considerations before enabling Multicast Routing

[Brian Maxwell]

I have a video application using Multicast and have been given a VLAN to use.  Hardware is Catalyst C3850 switches.  All on the same VLAN.  The customer requested that management interfaces on the switches be configured on the same VLAN as everything else so all addresses are on VLAN 1100 (their assignment).

Multicast works fine on the flat portion of the network.  IGMP Snooping was enabled by default and I've set our core switch as the Multicast Querier for VLAN 1100 and set the other switches to look to it as querier.

The customer now wants to use the application on their network which requires Multicast to be routed.  Near as I can tell, there isn't any configuration changes I need to make to get it working.  I did find that once they get Multicast routing running it may be desirable to remove my querier.

Question 1:  Am I missing something that is needed on my portion of the network?

He's trying to set the router to PIM-Sparse per our product requirements.  I see that my learning mode is pim-dvmrp though I don't think I have the ability to change it until multicast routing is enabled.

Question 2:  Is there something that I can do now to put my switches into pim sparse?

Thanks,

[Brian Maxwell]

Just in case, here is output of sh ip igmp snooping:

Global IGMP Snooping configuration:
-------------------------------------------
IGMP snooping : Enabled
IGMPv3 snooping (minimal) : Enabled
Report suppression : Enabled
TCN solicit query : Disabled
TCN flood query count : 2
Robustness variable : 2
Last member query count : 2
Last member query interval : 1000

Vlan 1:
--------
IGMP snooping : Enabled
IGMPv2 immediate leave : Disabled
Multicast router learning mode : pim-dvmrp
CGMP interoperability mode : IGMP_ONLY
Robustness variable : 2
Last member query count : 2
Last member query interval : 1000
Vlan 1100:
--------
IGMP snooping : Enabled
IGMPv2 immediate leave : Disabled
Multicast router learning mode : pim-dvmrp
CGMP interoperability mode : IGMP_ONLY
Robustness variable : 2
Last member query count : 2
Last member query interval : 1000

[Joseph W. Doherty]

Near as I can tell, there isn't any configuration changes I need to make to get it working.

That would seem unusual, as multicast routing normally requires some configuration changes, as its not enabled by default.

What would need to be done would depend on your current configuration and how you want to "do" multicast routing.

I.e. without know more, cannot answer your first question.

You mention of DVMRP might be a wrinkle.  Cisco routers (at least those I've used) don't fully support it.

 I did find that once they get Multicast routing running it may be desirable to remove my querier.

Yea, perhaps more so than even desirable.  Your multicast router gateway should assume the role of querier.

Question 2:  Is there something that I can do now to put my switches into pim sparse?

You can enable PIM Sparse on your interfaces, but there's more to setting up multicast than that.  Again, unclear what you have in place now.

[Brian Maxwell]

Sorry if I was unclear.

What I have in place now:  A flat network with one switch configured for IGMP Snooping Querier.  The only other commands issued on the other switches is to tell them that the core switch is IGMP Snooping Querier.

What the customer is trying to do:  Enable Multicast Routing on an Juniper / Avaya router.  (I am not privy to it's configuration and I am not trying to do any routing using my Cisco hardware).

I'm not sure how to quote in the forum but regarding your comments:

Once they have Multicast routing enabled, I'd set the router address as the querier

How can I enable PIM-Sparse on a flat network?  This is what i've been unable to find so far.

Based on my research, it's enabled on the router rather than the layer 2 switches.  Is that not correct?

thanks,