Subject: [MMUSIC] RTSP: a question about dest_addr parameter of RTSP 2.0

From: Kylin Wei <[email-masked]>
Date: Thu, 16 Nov 2006 18:53:34 +0800

Dear all,

Follow is the origin text of draft-ietf-mmusic-rfc2326bis-13.txt P97
>The lack of the dest_addr parameter indicates that the server
>SHALL send media to same address for which the RTSP messages
>originates.
>Transport: RTP/AVP;unicast;dest_addr=":8000"/":8001"

Can this work in Symmetry NAT condition? The mapped transport "dest_addr" IP
may be not equal the RTSP originates IP.

Kylin Wei 

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From: Magnus Westerlund <[email-masked]>
Date: Mon, 20 Nov 2006 13:56:19 +0100

> may be not equal the RTSP originates IP.

Not without an actual NAT traversal mechanism. The reason is that unless 
media is sent over the RTSP TCP connection there is no pinholes open. 
And if you do run a real traversal mechanism then you are likely to be 
able to provide the full address of the NAT.

Instead the mechanism is to allow for cases when providing the address 
does not make sense.

Cheers

Magnus Westerlund

IETF Transport Area Director & TSVWG Chair
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