Hey Jay, Try to disassociate the function of the DR from multicast sources. The DR has to do with multicast clients really. The DR basically has control of a segment that has multiple multicast routers on it for things like joins/leaves. A multicast source is going to send a SA message to the RP no matter where it is in the network. That doesn't have to do with the DR.
Remember -- DR in multicast is very similar to how it is in OSPF -- It just takes control of things when you have multiple routers on a segment. This is a seperate process from the SA messages and registration process between a source and the RP On Wed, Jul 15, 2009 at 8:06 AM, M Jay <[email protected]> wrote: > Hi, > finally someone replied me back :) thanks .. > > Ronald , is this means that Source directly sends SA messages to RP ? or > it sends these messages to DR and throgh DR RP gets the message ? > > > > > > Message: 8 > > Date: Tue, 14 Jul 2009 20:15:29 +0000 > > From: RONALDO NASCIMENTO <[email protected]> > > Subject: Re: [OSL | CCIE_RS] please help in understanding multicast > > To: <[email protected]>, > > <[email protected]> > > Message-ID: <[email protected]> > > Content-Type: text/plain; charset="windows-1252" > > > > > > 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. > > _________________________________________________________________ > > Show them the way! Add maps and directions to your party invites. > > http://www.microsoft.com/windows/windowslive/products/events.aspx > > -------------- next part -------------- > > An HTML attachment was scrubbed... > > URL: > http://onlinestudylist.com/pipermail/ccie_rs/attachments/20090714/4cdf23b0/attachment.htm > > > > End of CCIE_RS Digest, Vol 42, Issue 81 > > *************************************** > > ------------------------------ > Windows Live™ SkyDrive™: Get 25 GB of free online storage. Get it on your > BlackBerry or > iPhone.<http://windowslive.com/online/skydrive?ocid=TXT_TAGLM_WL_SD_25GB_062009> > > _______________________________________________ > 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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