From: Kevin M. Woods (kev@xxxxxxx)
Date: Tue May 23 2000 - 04:32:54 GMT-3
Think of PIM (or DVMRP, MOSPF, etc.) as you would an IGP routing protocol.
If you don't run OSPF then MC won't be able to reach MS. The same is true
for routing multicast, e.g. without PIM, MS cannot reach any group members
such as MC.
The 224.0.0.5 is a "link-local" address. All addresses in the range
224.0.0.0/24 should never be forwarded by a router _and_ should have a TTL
of 1 as an extra precaution. No configuration is necessary as the drivers
for the interface and other software take care of these addresses for you.
(All multicast addresses are taken care of in this fashion, but any router
should know not to forward packets to 224.0.0.0/24).
Any group addresses will work on a single segment. All one needs is a way
of getting interfaces to join the group requested. In this case multicast
routing is not needed. The multicasts will be seen whether the network is
shared or switched (which means you can get multicast to work across
network boundaries without multicast routing if all of the networks are in
the same VLAN).
Kevin
// I am starting to look at multicast routing a little closer now. I have a
// question about its functionality. If I have the following configuration
// MS---(e0)R1(s0)-------(s0)R2(e0)----(e0)R3(s0)-------(s0)R4(e0)----(e0)R3(s0
// )-------(s0)R5(e0)----(e0)R6(s0)-------(s0)R7(e0)------MC
// Where MS is a multicast server and MC is a multicast client, do I need to
// enable multicast routing on all routers and pim on all router interfaces?
// I know that I receive multicast traffic on my internet connection but my isp
// is not routing multicast traffic explicitly. That is, to say, it is not
// running pim. What about 224.0.0.5 (ALLSPFROUTERS)? You dont have to
// enable multicast routing to get that across your network. Where do you have
// to enable it and where dont you have to enable it?
//
// I am so confused!!! Any help is greatly appreciated!
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Earl Aboytes
// Senior Technical Conultant
// GTE Managed Solutions
// 805-381-8817
// earl.aboytes@telops.gte.com
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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