[infinispan-dev] DIST.retrieveFromRemoteSource

[Bela Ban]

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)


-- 
Bela Ban
Lead JGroups (http://www.jgroups.org)
JBoss / Red Hat