What is the best PIM mode for a campus video network? There are several relevant factors:

  1. All video is local to the campus.
  2. Click to view needs to be fast as possible (Life safety issues)
  3. Sources are intermittent.
  4. Bandwidth is not a concern in the selection as the campus is overbuilt in this regard. (shared tree is not required).
  5. Source and receiver are often on the same VLAN.
  6. Equipment can handle as many (S,G) entries as needed.
  • Approximately how many multicast sources are there, and what kind of core routers do you have? #6 is an issue more often than you think.
    – Ron Trunk
    Commented Feb 6, 2014 at 19:29
  • There are between 700 to 1000 cameras routing is accomplished between 4 4500-Xs in the campus.
    – henklu
    Commented Feb 6, 2014 at 20:05
  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Commented Aug 8, 2017 at 15:54

1 Answer 1


I’ve recently experienced a large network meltdown because of #6 using sparse mode, so maybe I’m a little gun-shy, but I wouldn’t recommend it for the number of cameras and the type of core routers you have. The problem occurred because lots of multicast sources (actually, first hop routers) were sending register packets to the rendezvous point, and the core processor couldn’t handle it all.

I would use SSM if your application will support it, or else use Bi-dir multicast.

  • Unfortunately the campus is currently running sparse mode and has never run right. I am currently looking to do a redesign and have considered SSM and just confirmed that the application will support it.
    – henklu
    Commented Feb 6, 2014 at 21:39
  • 2
    SSM is the way to go. If you know all of the possible sources in advance you can also configure SSM maps which would install "permanent" IGMP states on your 4500-x's. The benefit of this is that the Mroutes for the associate ssm map/igmp state are also "permanent". This can help IGMP converge rather quickly on a network. Commented Feb 7, 2014 at 14:52
  • SSM for stability.
    – Everton
    Commented Feb 10, 2014 at 17:39

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