From: William Nellis (nellis_iv@yahoo.com)
Date: Thu Nov 08 2007 - 01:57:49 ART
Going many -> Few then Few -> Many gets around the o^N problem you'll have in going many -> many...
ie, why does OSPF work the same way w/ having routers advertise LSA to DR/BDR only to have them readvertise it? Removes full mesh issues...
Realistically... i dunno. Probably has to do w/ limited processing power at the time AutoRP was invented, and being able to have beefier MA's do the computations. By having RP's just say "hey, I'm an RP", you can have them focus on doing RP stuff... like decapsulating registers. Then you have an MA do calculatoins for (what could be many c-RP), then advertise results of calculations out to all other routers who just follow orders. Otherwise, every router has to do calculations. May not be too much of an issue today... but... autoRP came out in the day of the 2500...
Thats my theory, but yeah, i know what you mean.
-------------------------------------------------------
r/s
William Nellis IV
nellis_iv@yahoo.com
----- Original Message ----
From: "Wollmann, Bruno RQHR" <Bruno.Wollmann@rqhealth.ca>
To: ccielab@groupstudy.com
Sent: Wednesday, November 7, 2007 9:29:19 PM
Subject: OT: Multicast Auto-RP
The document I'm reading right now while studying multicast and auto-rp
says that "all Cisco routers automatically join the Cisco-discovery
(224.0.1.40) group in order to receive group-to-RP mapping information
being multicast by the Mapping Agents in the network". The mapping
agent then advertises the C-RP with the highest IP address as the RP.
My question is, why bother with this step? Why don't the routers just
join the RP-announcement (224.0.1.39) group and learn the candidate RP's
right from the candidates themselves and then chose the one with the
highest IP address on their own. Why not learn it right from "the
horse's mouth" rather than a mapping Agent?
Anyone know the answer or have a logical explanation?
If you want to read what I'm reading for yourself check out page #7 at
ftp://ftp-eng.cisco.com/ipmulticast/training/Module6.pdf
thanks
Bruno
This archive was generated by hypermail 2.1.4 : Sat Dec 01 2007 - 06:37:28 ART