Re: [boost] Re: RPC library

From: Iain Hanson (Iain.Hanson_at_[hidden])
Date: 2005-03-09 11:25:34

On Wed, 2005-03-09 at 10:22 -0500, Caleb Epstein wrote:
> On Wed, 9 Mar 2005 08:45:52 +0000 (UTC), Jarl Lindrud
> <jlindrud_at_[hidden]> wrote:
> 
> > > As for messaging vs RPC, I think the same thing applies; it is easier to
> > > build an RPC layer on top of messaging than the other way around.
> > 
> > If you have oneway RPC's, why would it be difficult to build messaging on top of
> > that? The two seem to me to be almost the same thing.
> 
> Messaging is often built on top of a broadcast or multicast transport,
> so one does not need to locate or connect to a remote endpoint in
> order to publish messages.

In most, if not all messaging systems you do have connect to an end
point. The remote server provides various QoS and you need to register
your subject or channel and whether you are a push or a pull publisher.
Oh 8-) I think I'm re-inventing the CORBA Notification service. What a
surprise.

>   I don't think one-way RPCs are an adequate
> replacement for publish-subscribe semantics like these if you have a
> large fanout.
Simple one-way RPCs don't have a return value and can't throw exceptions
an so there not a good way for messaging if you want QoS other than best
efforts. The fan out is irrelevant using multi-cast.

/ikh