Subject: Re: [linux-audio-dev] Re: Audio synchronization, MIDI API
From: Steve Harris (S.W.Harris_AT_ecs.soton.ac.uk)
Date: Sun Sep 12 2004 - 23:02:19 EEST
On Sat, Sep 11, 2004 at 10:25:53AM -0700, Andrew Burgess wrote:
> >In pratice people dont really demand hard realtime and it will be OK, but
> >the maximum time taken to transmit a UDP packet is unbounded, it uses
> >exponential backoff IIRC.
>
> That sounds like TCP. I think UDP is send and forget, if you want guaranteed
> delivery or sequencing you need a higher protocol like TCP.
>
> Or are you thinking of ethernet level collision detect and retransmit? Does
> that go on forever (unbounded)?
I dont think so, but IP (including UDP) does. There is a difference
between raw ethernet packets and UDP.
Ethernet has checksums to detect problems (maybe in;c forward correction),
but AFAICR it doesnt retransmit on its own, I would imagine that that is
why the commercial audio-over-ethernet systems work.
- Steve
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