Not the way the RPCDispatcher in JGroups works.  I always pass in a List of buddies, and usually this list would have 1 element (if n=1).  Either way, even if n=3 in a 500 node cluster the multicast is inefficient.

(moving this to the JBC dev list)
--
Manik Surtani

Lead, JBoss Cache
JBoss, a division of Red Hat

Telephone: +44 7786 702 706
Yahoo/AIM/Skype: maniksurtani

On 5 Oct 2006, at 11:58, Ben Wang wrote:

I thought for BR, we do unicast now when there is only one buddy (the default) and switch to multicast where is more than one?

From: Bela Ban
Sent: Thursday, October 05, 2006 2:53 PM
To: Ben Wang; Brian Stansberry; Manik Surtani; Vladimir Blagojevic; Galder Zamarreno
Subject: Anycast

FYI,

currently, buddy replication generates the *same* amount of traffic as multicasting to everyone. I created a JIRA issue, anycast, which when implemented will allow for sending of messages to a subset of the membership: http://jira.jboss.com/jira/browse/JGRP-338
-- 
Bela Ban
Lead JGroups / Manager JBoss Clustering Group
JBoss - a division of Red Hat