[zeromq-dev] Heartbeats and/or keep-alives

[Martin Sustrik]

Marcelo,
> Coming at it from another angle, I understand that TCP itself supports 
> keep-alives via empty ACK packets. Would a very simple solution be to 
> expose the SO_KEEPALIVE socket option via a corresponding 
> ZMQ_KEEPALIVE? Of course, this would only be supported when using 
> "tcp://..." bindings, which may be the only time you'd need it, anyway.

That would be the best solution, as the only sane place to implement 
keepalives is OSI level 4. However, TCP specs (RFC1122) specify that 
keepalive timeout is at least 2 hours. It's a long-known and widely 
discussed problem with TCP. It have been solved in SCTP, but again, not 
everybody is willing to switch to SCTP, etc.

Martin