Ok, thanks for the explanation and doc reference. My A node spawns the B nodes in the first place, so I guess I can either (1) assign the identity out-of-band at spawn time and have the B use it, or (2) have B handshake once at start up to allow A to associate the zmq-assigned identity. After that B just receives and sends on DEALER; without other sockets connected there is no load balancing on B's end. Node A uses the identity association to send to a particular B and to recognize which B is sending when it receives a message.
-Jake On Wed, Feb 14, 2018 at 4:25 PM, Patrik Wenger <pad...@gmail.com> wrote: > Hi Jake > > In fact, most ZMQ socket types do some sort of load balancing when > connected with multiple other sockets. See [1], especially the "Outgoing > routing strategy" and "Incoming routing strategy" in the table for each > socket type. TL;DR if the socket allows receiving messages and is connected > to multiple other sockets, it will try to read from all of those sockets > "fairly". If the socket allows sending messages and is connected to > multiple other sockets, it will usually round-robin when sending. > > Of course PUB (and RADIO) will not round-robin, but "fan out" instead, > meaning all connected sockets will receive every message. > > And ROUTER is an exception too: When sending, it uses the first message > part (set by the application) to determine the correct receiver. This > allows you to send a message to one specific connected socket. When > receiving, it prepends a message part that identifies the socket which sent > the message. Your application will have to inspect that first part to know > who is its sender. These two things will have to happen in your A node. The > DEALER sockets in your B nodes will have to set an identity to be > distinguishable in A's ROUTER socket. > > Regards, > Patrik > > [1] http://api.zeromq.org/4-2:zmq-socket > > On 14.02.2018 20:17, Jake wrote: > > Isn't ROUTER-DEALER load balancing though? I've used it in a > REQ-ROUTER-DEALER-REP set up > but in that case the REQ -> ROUTER send does not target a particular > handler on the other side, it > just goes to an arbitrary one and the ROUTER makes sure the reply goes > back to the original sender. > How would my sender (an A node) target a particular B node to receive a > message? > > -Jake > > On Wed, Feb 14, 2018 at 12:34 PM, Justin Azoff <justin.az...@gmail.com> > wrote: > >> On Wed, Feb 14, 2018 at 12:28 PM, Patrik VV. <pad...@gmail.com> wrote: >> > Hi >> > >> > Not sure why Justin suggested using a ROUTER-Socket on each side. >> >> Ah yes, I misread the original message. For "one-to-many" you would >> use router-dealer. router+router would be more for many-to-many where >> each node runs the same code and there is no obvious master node. >> >> >> -- >> - Justin >> _______________________________________________ >> zeromq-dev mailing list >> zeromq-dev@lists.zeromq.org >> https://lists.zeromq.org/mailman/listinfo/zeromq-dev >> > > > > _______________________________________________ > zeromq-dev mailing > listzeromq-dev@lists.zeromq.orghttps://lists.zeromq.org/mailman/listinfo/zeromq-dev > > > > _______________________________________________ > zeromq-dev mailing list > zeromq-dev@lists.zeromq.org > https://lists.zeromq.org/mailman/listinfo/zeromq-dev > >
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