[Asterisk-Dev] Increasing reliability on lossy connections

[Mike M]

On Wed, Jan 12, 2005 at 09:27:51PM -0500, Steve Totaro wrote:
> > Actually  it's a small form of the PCR error correction method used on
> > satellite links.  Preventive Cyclic Retransmission periodically resends
> > unacknowledged PDUs until they are ack'd.
> 
> Same for connection oriented protocols and TCP.

Not exactly. Those protocols retransmit when there is an explicit form
of a nack.  In PCR there is no NACK because the latency is usually quite
high.  In PCR the protocol assumes that if an ack didn't come in n units
of time, then it's best to send another and let the far end deal with 
possible duplications.