On Mar 5, 2010, at 12:04 PM, Martin Sustrik wrote: > Martin Lucina wrote: > >> Yes, but once you introduce sequence numbers you're going to need a >> handshake to initialise those, which means a "virtual connection" of some >> sort, and if you want to do that using multicast I guess you'll end up with >> something like PGM anyway :-) > > No. You need no negotiation. Receiver just has to handle first seqnum it > sees as beginning of the stream and wait for following packet. Any > larger seqnum means the stream is disrupted at that point. Any lower > seqnum means the sender was restarted. > > It may cause some hickups when packets are reordered, but that doesn't > really matter, it's unreliable anyway. >
Yes. My intent isn't trying to use Zeromq to build reliability on top of the unreliable multicast. It's more as an abstract framework for switching the underlying transport to deliver "multicast" message. > Of course, multiple senders would make a mess. > I think that should be pushed to the application layer to decide. Zeromq as a framework wouldn't have a better idea on how to handle that anyway. After all, we're talking about multicast... >> I guess the answer depends on what applications Chris has in mind. > > Definitely. The applications I have in mind belong to the category where message is idempotent and only the latest "version" is important. So, if message was lost, a later version will arrive in the next period anyway. Old version that arrives out of sequence will be discarded by the app. Chris > > Martin > _______________________________________________ > zeromq-dev mailing list > [email protected] > http://lists.zeromq.org/mailman/listinfo/zeromq-dev _______________________________________________ zeromq-dev mailing list [email protected] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
