Hehehe, it's becoming clearer and clearer each time :)) Misunderstanding may be due to my bad english.
Anyway, thank you Kent for the help. Kent Yu wrote: > > ""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=51547&t=51458 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
