[Asterisk-biz] h323 is a dying standard?

[Emilio Panighetti]

Actually:

H.323 is an ITU-T Umbrella specification, in the same fashion as ISDN 
protocol or the SS7 standard is for TDM networks.
SIP is a protocol pushed by the IETF, so it doesn't have lots of the 
baggage of a traditional telephony protocol and is engineer around the 
HTTP/HTML communication concept.

I agree that H.323 might be over engineered, but it offers some nice 
features that I don't see in SIP, like it carries the full Q.931 
completion codes in the same way ISDN or SS7 does. It uses TCP instead 
of UDP but that is better when metering calls with millisecond 
precision. It also lessens the chance of hung calls by IP network 
congestion, etc.

Working with H.323 for the past 5 or so years, I agree that SIP is so 
much simpler to work with, and H.323 seems more complex that needs to 
be, but once it works, is very, very solid.

H.323 wasn't created by Cisco. Actually, circa 1998, when Cisco came 
out with AS5300 routers, most others were using proprietary 
technologies. H.323 was being pushed mostly for video-conferencing 
systems (reason why Polycom is an early adopter of H.323).
SIP is fairly new compared to H.323/H.245 and was originally developed 
for multiparty conferencing at Columbia U.
Because SIP is maturing, and is easier to work with and has some call 
control features that were designed from the ground up as an IP 
protocol, it will over time replace H.323, and many carriers are 
migrating to SIP. A prime example is Level3, which operates exclusively 
in SIP.
Most 'big iron' hardware actually does SIP.
Legacy equipment like Vocaltec or Clarent are actually Windows-PC 
based, and never did H.323 too well anyways (Because of their 
proprietary software stack, not because of the ill-choice of OS). 
(Hint: Maybe somebody could make * run on these legacy hardware), and 
IMHO weren't well suited to compete with appliances from Cisco, etc.

E.

On Jan 26, 2005, at 9:36 PM, Kenneth Long wrote:

> <my $0.02>
>
> H.323 was Created/Chaired/Dominated by Cisco Systems.
> SIP was invented by Telcordia/Others to compete and
> take market share away.
>
> Same goes with MGCP (cisco) versus MEGACO (nortel).
>
> The value of the protocol depends on who is selling
> what. Nothing more.
>
> </my $0.02>
>
>
> --- Michael Bielicki <cypromis at gmail.com> wrote:
>
>> On Wed, 26 Jan 2005 15:24:17 -0800, Tracy R Reed
>> <treed at copilotconsulting.com> wrote:
>>> On Wed, Jan 26, 2005 at 02:35:35PM -0800, Alex Pui
>> spake thusly:
>>>> On page 25 of Paul Mahler's "VOIP Telephony with
>> *", he said "While H323
>>>> support is present in Asterisk, H323 is a dying
>> standard. Whenever possible
>>>> you should use a more modern interface like SIP
>> or IAX".
>>
>> H.323 is the primary inter operator and termination
>> protocol. As Craig
>> Southeren correctly stated at the GUUG Telephony
>> Summit it simply
>> refuses to die :D You will find that to push large
>> quantites of
>> traffic to close to any place in this world you will
>> require H.323 and
>> nobody in that league will accept anything but
>> H.323.
>>
>> Just my 2cents EUR
>>
>> cheers
>> Michael
>>
>>
>> -- 
>> Michal Bielicki
>> http://www.asterisk.com.pl/
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>
>
>
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