"H.323 Annex E".

Unanswered Question
Aug 16th, 2007

Has anybody known where Cisco uses "H.323 Annex E". Recently there is a psirt announced on the following link


one of the vulnerability is attacked on "H.323 Annex E" which is udp 2517. But I never seen this being used in Cisco world. Anybody knows this? Thanks

I have this problem too.
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gogasca Thu, 08/16/2007 - 21:13

H.323 Annex E - Faster Connection Method

This Annex specifies the optional use of UDP instead of TCP, and the optional use of fixed-format packet encoding instead of the

more processor-intensive ASN.1 encoding.

It is supported from 12.2(11)T.

conf t

voice service voip


session transport udp

For restrictions refer this,


ciscoforum Fri, 08/17/2007 - 07:35

Thanks. I know that by default it uses tcp 1720. So when we configure it as udp, it will use udp port 2517?


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