The designated router was added for backward compatibility with IGMPv1. IGMPv1 had does not have a querier process and relies on whatever routing protocol you are using to elect the designated router to control IGMP queries. IGMPv2 added the capability to query for neighbors seperate from the multicast routing protocol and hence the designated router is a non-issue. I believe Doyle Vol.II has a real good explanation of this.
HTH, Scott CCIE #9340 ""Priscilla Oppenheimer"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > Oh, I'm sorry I gave you the basic answer when you're looking for an > advanced answer! Can someone help us out here? This is beyond me. Thank-you! > > Priscilla > > richard dumoulin wrote: > > > > I already read this in your awsome certification study guide > > (congrats, it was very helpful). But I was not asking for this. > > I am actually confused by two terms: IGMP querier and Multicast > > Designated Router. > > I have read somewhere that an IGMP querier is elected in a > > multiaccess network (ie ethernet) to query the hosts for their > > multicast group membership. The router with the lowest IP > > address is elected as the querier. > > > > But it is also said that a Designated Router is elected (the > > one with the higher IP address) to query the hosts for their > > multicast group membership, and in case of PIM Sparse mode, it > > also sends the join and leave multicast group membership to the > > RP. > > > > My confusion comes from the fact that there will be two routers > > querying the hosts ?? > > > > Regards. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=51471&t=51458 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
