[zeromq-dev] Subports

[Pieter Hintjens]

On Tue, May 3, 2011 at 9:51 PM, Martin Sustrik <sustrik at 250bpm.com> wrote:

> Ah, right! No, the idea is to have many TCP connection sharing same
> destination port (the source port will be different for every connection
> though).

Yes. Standard TCP in every sense, and on top of that, 0MQ-level
negotiation to say, "ok, I've connected to port 5555 but please, I
really want to talk to service XYZ!", which the 0MQ layer above TCP
handles to send that specific connection to the socket that bound on
port 5555 specifying service XYZ.

Typical use case, a forwarder device that has 'frontend' and 'backend'
sockets, could run over a single port with two named services. Today,
requires two ports. With a single port, it becomes *much* easier to
construct topologies. The device is at address 192.168.55.123:5560,
period.

There are many applications for this. E.g. encrypted / plain traffic
across one port, versions of a protocol across one port, etc. It's an
extremely valuable asset in a smart transport layer, IMO.

Martin, please don't abandon because it only works in one process.
That fits perfectly with every actual use case I can think of, and
there are loads of them...

-Pieter