[zeromq-dev] What exact networking problems ZMQ does solve?

[Justin Cook]

Artem,

This is a problem that every network developer faces. Did my message make it to its destination? If I send a message, is it likely to make it to the recipient?  

Fortunately, there are patterns to use to increase reliability, but even then there is no way to be 100% sure that when a message is sent, it will flow across the infrastructure and be delivered with 100% certainty without an acknowledgement.

You cannot _instantly_ get an indication a server failed — or the associated infrastructure — unless you have a steady stream of bytes going across the wire, and they suddenly stop. If you want to know a node went down, you will need heartbeat messages. There are a few ways to do this.  

Please look at the paranoid pirate example and this:

http://zguide.zeromq.org/page:all#Heartbeating  

--  
Justin Cook


On Wednesday, 11 December 2013 at 09:59, artemv zmq wrote:

> Okay. Thanks for your thoughts. Again, I read the guide, and I know on practice what's pub/sub/push/pull/ .. and so on.  
>  
> But let me ask one more time very concrete and simple question. I want to develop a client/server appl. Okay. I pick dealer/router pattern. Fine. Now my requirement is following:  
> if server is unaccessible (wrong ip address, server is not online, server was online and then went offline, etc.) -- in this case I want to get (_instantly_) some indication that client can't send a message because server is unaccessible. It's clear? Again, I don't want to await for reply, I want to know right now that I can't send a message.  
>  
> Realistically, this is very classic networking issue :) So, how can ZMQ help me? Or is it possible/eligible et al to implement transactional (not batching!) applications on ZMQ?
>  
>  
> BR
> -artemv
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> 2013/12/11 Bruno D. Rodrigues <bruno.rodrigues at litux.org (mailto:bruno.rodrigues at litux.org)>
> > zeromq.org (http://zeromq.org) - learn the basics - http://zeromq.org/intro:read-the-manual - the guide - http://zguide.zeromq.org/page:all  
> >  
> > I just gave you a short description of how Ømq is solving the network problems for me.  
> >  
> > On Dec 11, 2013, at 6:59, asif saeed <asif.lse2 at gmail.com (mailto:asif.lse2 at gmail.com)> wrote:  
> > > Hi Bruno,
> > >  
> > > On Wed, Dec 11, 2013 at 12:38 AM, Bruno D. Rodrigues <bruno.rodrigues at litux.org (mailto:bruno.rodrigues at litux.org)> wrote:
> > > > Xsub xpub for distribution load balancing
> > >  
> > >  
> > > What is Xsub xpub? Could you please explain these terms or give me a link to an online resource where these terms are explained in detail?
> > >  
> > > Thanks in advance,
> > > -Asif
> > >  
> > >  
> > >  
> > >  
> > >  
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