On 25 Jan 2012, at 12:06, Bela Ban wrote:



On 1/25/12 12:58 PM, Mircea Markus wrote:

On 25 Jan 2012, at 09:42, Bela Ban wrote:



On 1/25/12 9:51 AM, Dan Berindei wrote:

Slightly related, I wonder if Manik's comment is still true:

    if at all possible, try not to use JGroups' ANYCAST for now.
Multiple (parallel) UNICASTs are much faster.)

Intuitively it shouldn't be true, unicasts+FutureCollator do basically
the same thing as anycast+GroupRequest.


No, parallel unicasts will be faster, as an anycast to A,B,C sends the
unicasts sequentially
Thanks, very good to know that.

I'm a a bit confused by the jgroups terminology though :-)
My understanding of the term ANYCAST is that the message is sent to *one* of the A,B,C. But from what I read here it is sent to A, B and C - that's what I know as MULTICAST.


No, here's the definition:
* anycast: message sent to a subset S of members N. The message is sent
to all members in S as sequential unicasts. S <= N
* multicast: cluster-wide message, sent to all members N of a cluster.
This can be done via UDP (IP multicast) or TCP
* IP multicast: the network level datagram packet with a class D address
as destination
* broadcast: IP packet sent to all hosts on a given range same host,
subnet or higher)
Thanks for the clarification Bela. I've been using wikipedia[1]  as a reference and the terms have a slightly different meaning there.

[1] http://en.wikipedia.org/wiki/Anycast#Addressing_methodologies