""richard dumoulin"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > In an ealier statement, you said that a DR PIM router does not query hosts, > right ? If you do not agree, I can quote it.
I can quote this myself, here is what I said:" As we mentioned yesterday, only routers speak PIM, I am not sure where you got the impression that PIM DRs query the hosts, routers only use IGMP to query the hosts." If you read the last sentence, what I meant was PIM DRs do not talk PIM to hosts, I did mention it only uses IGMP to query hosts. Your email gave me the impresson you believed PIM DR queries hosts using PIM, if that was not what you meant, I guess I just misunderstood it. >You argued that the rfc did > not mentioned anything about having a PIM router IGMP querying hosts. Please quote this for me, I do not remember I said this. >So > based on this quote (I did not checked the rfc), I assumed that Cisco IOS > implemented it his own way (as usual, that's the purpose of an rfc) and had > a DR PIM router query hosts too. But my conclusion, after this useful > discussion, is that in case of having IGMP v2, the PIM router will not query > hosts. But the IGMP v2 will. For IGMP v2, PIM DR may or may not be the IGMP querier, for v1, it is. Again, the first place I read you saying PIM DR queries the hosts, I thought you meant they use PIM to do that. > > Another conclusion is that I still have a lot to study. RFC's, Cisco press > books, etc ... Same for everybody, I guess. Kent > > > ----- Original Message ----- > From: "Kent Yu" > To: "richard dumoulin" ; > Sent: Friday, August 16, 2002 9:45 PM > Subject: Re: Multicast DR and IGMP querier [7:51458] > > > > Sorry I still do not get it, this is not an added capability from IOS, > this > > is stated in RFC. > > In your early email, you questioned: > > > > >>>With IGMP version 2 it > > > > > seems you do not need it. But what happen then if you have both IGMP > > v2 > > > > and > > > > > PIM DR's ?? Do they both query the hosts ? > > > > I am not sure what the question means, the interface either runs IGMP v2 > or > > v1, if it is running v1, the DR selected by the PIM sends IGMP query > > messages. If it is running > > v 2, the lower ip is the querier, in v 2 it does not matter who the DR > is. > > > > It is also a bit confusing the way Routing TCP/IP Volume II describes DR > ( I > > have not checked with the book, just based on your quote), it first says > > PIM-DM does not need a DR, this is right, but it also says: " This is the > > role of the PIM-DM (and PIM-SM) designated router ", IMHO, this is not > very > > accurate, the role of DR in DM is for IGMP v1 but in SM, as you mentioned > in > > your yesteardy's email is mainly responsible for forwarding the join/prune > > messages to the RP, of course, it is also useful for IGMP, if v1 is > running. > > > > Kent > > > > ----- Original Message ----- > > From: "richard dumoulin" > > To: "Kent Yu" ; > > Sent: Friday, August 16, 2002 2:10 PM > > Subject: Re: Multicast DR and IGMP querier [7:51458] > > > > > > > Ok, > > > > > > " PIM-DM elects a designated router on multiaccess networks. The > protocol > > > itself does not need a DR, but recall that IGMPv1 does not have a > querier > > > process and relies on the routing protocol to elect a DR to manage IGMP > > > queries. This is the role of the PIM-DM (and PIM-SM) designated router " > > > > > > Chapter 5 page 484 of Routing TCP/IP Volume II > > > > > > > > > Regards. > > > > > > Note: Scott is right, Multicast is wonderfully explained in this book. I > > > just have to find time to read all that books ;)) > > > ----- Original Message ----- > > > From: "Kent Yu" > > > To: "richard dumoulin" ; > > > Sent: Friday, August 16, 2002 7:06 PM > > > Subject: Re: Multicast DR and IGMP querier [7:51458] > > > > > > > > > > If that's the case, I am confused too, could you show us the link from > > > cisco > > > > explaining this > > > > added capability you mentioned? From reading your email, I am not even > > > clear > > > > what this added capability it is about. > > > > > > > > > > > > Thanks > > > > Kent > > > > > > > > ----- Original Message ----- > > > > From: "richard dumoulin" > > > > To: > > > > Sent: Friday, August 16, 2002 11:29 AM > > > > Subject: Re: Multicast DR and IGMP querier [7:51458] > > > > > > > > > > > > > Here it is !! That was my confusion, because it seems that this > > > > capability > > > > > was added in order to query IGMP version 1 hosts. With IGMP version > 2 > > it > > > > > seems you do not need it. But what happen then if you have both IGMP > > v2 > > > > and > > > > > PIM DR's ?? Do they both query the hosts ? > > > > > > > > > > Any Multicast expert right there ? > > > > > > > > > > Regards. > > > > > ----- Original Message ----- > > > > > From: "Kent Yu" > > > > > To: "richard dumoulin" ; > > > > > Sent: Friday, August 16, 2002 4:42 PM > > > > > Subject: Re: Multicast DR and IGMP querier [7:51458] > > > > > > > > > > > > > > > > Do you mean that in IOS if a router is running PIM and is a DR, > it > > > will > > > > > > query even if it sees IGMP query messages from another router with > > > lower > > > > > ip > > > > > > address? > > > > > > > > > > > > Kent > > > > > > > > > > > > ----- Original Message ----- > > > > > > From: "richard dumoulin" > > > > > > To: "Kent Yu" ; > > > > > > Sent: Friday, August 16, 2002 10:34 AM > > > > > > Subject: Re: Multicast DR and IGMP querier [7:51458] > > > > > > > > > > > > > > > > > > > RFC's are great, but have to look also at how Cisco IOS > implements > > > the > > > > > > rfc. > > > > > > > PIM DR's use IGMP to query the hosts too !! > > > > > > > > > > > > > > Regards. > > > > > > > ----- Original Message ----- > > > > > > > From: "Kent Yu" > > > > > > > To: "richard dumoulin" ; > > > > > > > Sent: Friday, August 16, 2002 4:20 PM > > > > > > > Subject: Re: Multicast DR and IGMP querier [7:51458] > > > > > > > > > > > > > > > > > > > > > > Richard, > > > > > > > > > > > > > > > > As we mentioned yesterday, only routers speak PIM, I am not > sure > > > > where > > > > > > you > > > > > > > > got the impression that PIM DRs query the hosts, routers only > > use > > > > IGMP > > > > > > to > > > > > > > > query the hosts. > > > > > > > > > > > > > > > > I think as many have suggested, nothing is better than reading > > the > > > > > > specs, > > > > > > > in > > > > > > > > this case, RFC 2117 should explain this pretty well. > > > > > > > > > > > > > > > > HTH > > > > > > > > Kent > > > > > > > > > > > > > > > > ----- Original Message ----- > > > > > > > > From: "richard dumoulin" > > > > > > > > To: > > > > > > > > Sent: Friday, August 16, 2002 3:47 AM > > > > > > > > Subject: Re: Multicast DR and IGMP querier [7:51458] > > > > > > > > > > > > > > > > > > > > > > > > > Raj Santiago wrote: > > > > > > > > > > > > > > > > > > > > Hi Richard, > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Okay your question is basically what is a "IGMP querier > and > > > > > > > > > > Multicast Designated Router" > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Igmp querier is the router in charge to see if any hosts > > want > > > > > > > > > > to listen to a multicast stream. > > > > > > > > > > > > > > > > > > > > Designated Router is the router is charge to facilitate > pim > > > > > > > > > > join, prune and register messages(This also depends on > the > > > > > > > > > > mode of pim your running, im being very abstract here); > > > > > > > > > > Basically the multicast routing part. > > > > > > > > > > > > > > > > > > But it seems to me that the DR will also query the hosts!! > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Under IGMP version 1, the router with the highest ip > address > > > > > > > > > > was BOTH the IGMP querier and Designated Router. > > > > > > > > > > > > > > > > > > > > Under IGMP version 2, the router with highest ip address > is > > > the > > > > > > > > > > DR and the router with the lowest ip address is the IGMP > > > > querier. > > > > > > > > > > > > > > > > > > If I am right, both the DR and the querier will query the > > hosts > > > ?? > > > > > > > > > > > > > > > > > > > > > > > > > > > Cheers. > > > > > [EMAIL PROTECTED] > [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=51544&t=51458 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
