What Ronaldo said is correct. I think it is important to note that the MA has nothing to do with receiving requests from clients -- All the MA does it announce the RPs. The RPs take the requests from the clients. Regarding the DR, Ronaldo is correct.
On Tue, Jul 14, 2009 at 4:15 PM, RONALDO NASCIMENTO <[email protected]>wrote: > Hi, > > My understanding is that the DR election takes place only because you may > have multiple routers on a given network (i.e., LAN) so one needs to be > elected, a DR, in order to send/receive IGMP report messages to RP and > minimize traffic that way. > > The Mapping Agent (MA) learns and build tables showing respective group > address and RP address. It sends a multicast message "RP-Discovery" to > 224.0.1.40 group and from there routers can learn which are the RP's for the > respective group. > > Ronaldo Nascimento > > > > > > ------------------------------ > From: [email protected] > To: [email protected]; [email protected] > Date: Mon, 13 Jul 2009 13:20:08 +0000 > Subject: [OSL | CCIE_RS] please help in understanding multicast > > > > Hi, > I need help in understanding IP multicasting specially sparse > mode.... bit confused > In sparse mode we have a RP and Maping Agent (MA). RP announces its self > to MA and MA receives the request from clients to join a specific multicast > group for which RP is configured or MA announcing. Source send the source > active message to the RP for multicast group it has. Now my question is that > whats the function of PIM DR how it works I just know that PIM DR is elected > on the bases of higher priority or the higher IP Address. > how PIM DR works in relation with RP or MA > If I am not wrong Source sends unicast packets to PIM DR for specific > group then DR sends those packets to RP and then RP register itself with DR. > if its right then its mean Source dosent communicate with RP ?? > Please someone help > > Thanks > > > ------------------------------ > Windows Live™ Photos: it's easy to store and manage your photos online. See > how.<http://windowslive.com/Online/Photos?ocid=TXT_TAGLM_WL_CS_PH_store_manage_072009> > ------------------------------ > See all the ways you can stay connected to friends and > family<http://www.microsoft.com/windows/windowslive/default.aspx> > > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > -- Regards, Joe Astorino - CCIE #24347 R&S Technical Instructor - IPexpert, Inc. Cell: +1.586.212.6107 Fax: +1.810.454.0130 Mailto: [email protected]
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