[zeromq-dev] 0MQ experimental OpenPGM support

Pieter Hintjens ph at imatix.com
Tue Jan 20 16:39:49 CET 2009


On Tue, Jan 20, 2009 at 4:37 PM, Martin Sustrik <sustrik at fastmq.com> wrote:

> The difference is that PGM tx window is rolling on with every message you
> send - thus, if consumer requests retransmission of a packet that was
> already rolled out of the window "connection" breaks. With TCP sender will
> be blocked when tx window is full. In other words, PGM is somehow less
> reliable than TCP.

You're saying that on saturated networks, PGM will drop packets but
continue working while TCP/IP will block.  And on unsaturated
networks, PGM will be as good but obviously with the multicast
advantages?

This sounds great, especially for time sensitive data that loses its
value when it gets old.

Do we know when data is lost?  Sorry if these questions are answered
somewhere already...

-Pieter



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