All things related to multicast

[Bob Riddle <>]

actually, Dan could be describing the way the AG currently works - where there are multiple sources to the same multicast "stream".  In that case having a "load balancer" might be able to decide which "sources" to let flow into your network.

Perhaps a load balancer might limit, by bandwidth the number of multicast groups you will permit to flow into your network.  Normally, when you "leave" a multicast session, it takes several minutes for the edge router to notice & quit sending the flow.  Thus, if you leave a multicast session & join another, leave it & join another ... you could have a period of time when you have more streams being pushed across your network than you have capacity to handle ...

Dan Pritts wrote:

On Mon, Jan 24, 2005 at 11:36:21AM -0500, Charles R. Anderson wrote:
  

On Mon, Jan 24, 2005 at 11:20:37AM -0500, Jay Young wrote:
    

One of our groups on campus is using a real media server to stream media 
across campus, they have it setup to use multicast as well. They are 
wanting to setup a load balancer in front of multiple servers.
      

Why load balance multicast?  No matter how many clients, you still 
have only one stream transmitted from the server...
    

I would imagine that they want to load-balance the servers to
support unicast clients - and don't want to set up a separate server
infrastructure just for multicast.

I don't know enough about how real server handles multicast but one
thing i would look for is the possibility that different clients will
request multicast when connected to different servers, and each server
will then send its own multicast stream, probably with entertaining (but
not desirable) results.  Ideally your load balancer will know enough
about the realserver protocol to redirect all multicast requests to a
designated multicast source.


danno
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dan pritts - systems administrator - internet2
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