streaming guru needed

Bakul Shah bakul at
Thu May 10 04:04:23 UTC 2007

> >This is not right.  The OP seem to have misunderstood rtsp.
> >It has been a while but from what I remember rtsp does not
> >have acks as it was designed to work the same way over udp
> >and tcp and A/V can tolerate loss of a few packets so no
> >sense in having acks.
> No, you're the one who's misunderstanding.  RTSP is the 'control 
> protocol'.  It always runs over TCP.

It _has_ been a while :-)  I was thinking of the media
delivery portion only, not the control portion.  In any case
rtsp does not have acks and yes technically it can be over
udp and yes, you can interleave media data on the same
session so it is not a pure control protocol either (though
you can think of it as such).

The spec says:

   An RTSP session is in no way tied to a transport-level
   connection such as a TCP connection. During an RTSP
   session, an RTSP client may open and close many reliable
   transport connections to the server to issue RTSP
   requests.  Alternatively, it may use a connectionless
   transport protocol such as UDP.

Though it is likely this was left over from some earlier rev.
I no longer recall if (one of) the starting point(s) for RTSP
was RTTP2, an internal Real Networks effort, but I assume so
given Rob Lanphier is one of the RFC authors but I don't
really know.  In any case RTTP2 could go over either UDP or
TCP and I will admit I was thinking of that!

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