Question on a NAT traversal requirement

OKUBO Sakae okubo at MXZ.MESH.NE.JP
Tue Aug 22 04:09:55 EDT 2006

Dear NAT traversal experts,

TTC (The Telecommunication Technology Committee) is now working on 
Technical Paper "Requirements for Network Address Translator and 
Firewall Traversal of H.323 Multimedia Systems" to convert it to a 
Technical Report in Japanese language.

I have a question on how to interpret the following part:

9.3	Requirements on Signalling and Media Streams
b)	NAT traversal mechanisms for H.323 multimedia systems shall 
support no less than ITU-T H.323v3, H.245v7, H.225.0v4, and H.235v3. 
All later versions of H.323, H.245, H.225.0 and H.235 may be 

Take an example of H.323 that has now v6. Which of the following 
statements are true?

NAT traversal

1/ shall not support v1 or v2.
2/ may support v1 or v2.
3/ shall support v3.
4/ shall support v3 and in addition may support any combinations of 
v4, v5 and v6.
5/ shall support v3 and may support v4, or (v4 and v5), or (v4, v5 and v6).

In other words, NAT traversal with the following support conforms to 
this requirement:

a/ v3
b/ v4
c/ v5
d/ v6
e/ v3, v4
f/ v3, v5
g/ v3, v6
h/ v3, v4, v5
i/ v3, v4, v5, v6
j/ v4, v5
k/ v4, v6
l/ v4, v5, v6
m/ v5, v6

Best regards,

e-mail: okubo at
         (<== sokubo at, valid until 31 March 2007)
Visiting Professor
Global Information and Telecommunication Institute (GITI)
Waseda University
Waseda University, YRP Ichibankan 312        Tel: +81 46 847 5406
3-4 Hikarinooka, Yokosuka-shi, Kanagawa-ken  Fax: +81 46 847 5413
239-0847 Japan
                       H.323 videoconferencing: arranged by advice

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