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
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