Re: [MMUSIC] RTSP "alt-ports" are not mentioned in the RFC.

[Ross Finlayson <[e-mail]>]

(Grumple... I wish this mailing list were set up so that replies went to the mailing list by default.  Resending to the whole mailing list instead of just Magnus.)

> The question is if this port number has any benefit at all.

Yes it does.  If a RTSP server cannot use port 554 (most likely because it is running on a Unix system, but not as 'root'), then it can try using port 8554 instead.  (FWIW, our RTSP server implementation - widely used on the Internet - does this.)  As you noted, if a server uses port 8554 (or any port other than 554), then this port number will need to be included in the "rtsp://" URLs that clients use.  But it's beneficial to know - e.g., if you're managing a network's 'security' policy - that RTSP will likely be used on either port 554 or port 8554 (rather than either port 554 or some unspecified other port number).  Similarly, it's useful for network monitoring tools to know that traffic on port 8554 is likely to be RTSP.

Ross Finlayson
Live Networks, Inc.
http://www.live555.com/