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Wednesday, June 21, 2006

H.325 - Is a rehash necessary ?

At the 2006 ITU-T workshop, a presentation was made on the 'next' generation of protocols 'H.325' !

The primary pitch for H.325:
a) It offers a 'centralized' model of operation, as opposed to SIP and H.323 which put intelligence in the device. SIP cannot do this (*cough* tell this to the SIP centrex guys *cough* B2B)

Secondary pitches for H.325 :
b) Reduced Complexity ( haven't we heard that before)
c) Rapid Service creation (we have seen this on marketing slideware for years)
d) Better 'capability negotiation' (which does not need a new protocol - its a behavioural change that can be adapted to any existing protocol)
e) "Truly" take advantage of IP networks (not sure what that really means)
f) Better NAT/FW traversal (enough already ! we have come to a point where Sykpe's NAT traversel works everywhere. Why bother again ?)
g) It says "SIP is largely equated to voice" (not at all, really)

And finally:

"H.325 was launched by ITU SG-16 to meet NGN requirements and overcome limitations of 'legacy' systems" - oh brother ! Join the queue please, we have 3GPP, 3GPP2, TISPAN and a bunch of other SDOs trying to 'solve the next generation' problem.

The interesting part is that H.325 is a 'new effort' with requirements being confirmed by end 2007 and 2008 being the year for the protocol definition.

We spent till 2000 battling between protocol choice for deployment (SIP vs. H.323). For good or for worse, that battle was won by SIP. Today, we have 3GPP, TISPAN, IPTV, Cable and several other forums who have brought out architectures that meet initial requirements for their respective networks. More importantly, OEMs and carriers have invested billions of dollars in getting those networks ready, with SIP support.

Is this really a time to launch YAAAPHWANH ? (Yet Another Attempt At Promoting H.323 With Another New H.325 ?)

I personally think this is an effort which is too late. Some of the problems are real - but instead of blowing off the dust of a has-been protocol and adding bells to it, why not add the missing features to SIP ?


  1. The definition of H.325 is still in progress, so it is neither centralized or decentralized.

    However, there are a lot of problems with SIP and H.323. They are 11 year old protocols that do not deliver more than just voice and video. It is virtually impossible to add any new functionaity to a SIP phone, for example. Where is app sharing? Whiteboarding? The concepts behind H.325 enable multiple application providers to provide applications that connect to H.325 and become a part of user's capabilities. Just as one example, you can use your mobile phone to view an HDTV transmission, with the video delivered directly to the TV, not to the mobile device.


  2. H.323 and SIP are "over IP" protocols designed as were designed other "over IP" protocols use for DATA over Data Networks, more or less seamless protocols. Trouble is that the aim of VoIP is one day or another to replace the good old PSTN voice Network. Operators will then offers full VoIP service with some portability of public phone numbers and the same level of service that PSTN was achieving. But to be able to do that, they will need another notseamless architecture and protocols as there were organized on the PSTN. H.323 and SIP are all the way through. There are both public and private at the sametime, they won't match.