Subject: Why send Prunes on Multicast addr

From: vishwas <[email-masked]>
Date: Thu, 12 Nov 98 14:05:00 PST

Hi All,
 What if we unicast the prune to the upstream rather than Multicasting it   
and facing all those overheads on timers and increase in control trafic   
by prune overrides.

It seems prunig with unicast address seem to work fine. Upstream can have   
a well defined datastructure containing a linked list of neighbors per   
outgoing interface. And when all the neighbors get pruned he can then   
prune the interface itself. And if all the outgoing interfaces get   
pruned, prune the upstream, again UNICAST.

Comments PLEASE...!!!!

Regards
S. Vishwanath
 --------------------------------------------------------------------------  
 ------------------------
Software Engineer, Future Software Pvt. Ltd, Chennai, India
Ph : +91-44-4330550 (335)
Private e-mail : [email-masked]

---

From: [email-masked] (Hal Sandick)
Date: Thu, 12 Nov 1998 17:03:36 -0500

Vishwas,

If I undersatnd you correclty, this would require a list of neighbors for
each LAN oif on  each (S,G) entry.  You'd also have to have timers for each
neighbor on each list.  This seems like way more overhead then it would save. 

Regards,

Hal

---

From: Bill Fenner <[email-masked]>
Date: Mon, 16 Nov 1998 09:14:15 PST

PIM-DM needs the multicasted prune and prune-override function for
two reasons:

1) PIM routers don't keep track of their subordinate routers; if
you have multiple equal-cost paths to a LAN, for example, Asserts
will happen and a winner will be picked but the Assert loser(s)
would have no reason to send a prune to the Assert winer.  The Assert
winner doesn't necessarily have knowledge of who the losers are.

2) The downstream routers might not know the right upstream router;
see the last paragraph of section 5.2.1 .

  Bill