Subject: Re: Handling of Setup message by Gatekeeper.

From: "ronald h. davis" <[email-masked]>
Date: Wed, 10 Mar 1999 10:44:21 -0600

[email-masked] wrote:
> 
> I agree that GK is responsible only for the endpoints whixh exist in its
> zone. And also that it can not administer endpoints in other zones. But the
> scenarios mentioned in the query are all valid scenarios. GK CAN receive
> Setup message without any RAS signalling taking place before that. So it
> can not terminate h225 signalling channel because of absence of RAS
> channel.
> 

i think that i don't understand what you're trying to say.  the setup
message is an h.225 call signalling message, not a ras message.

-- 
  __  ______  __  / __/ |       lucent technologies, naperville il, usa
_/ (_(_) / (_(_/_/_(_/  .       [email-masked]
"if you ain't the lead dog, the scenery never changes"  -- edmund wilson

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This message came from the IETF IPTEL Working Group Mailing List.

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From: "ronald h. davis" <[email-masked]>
Date: Wed, 10 Mar 1999 10:44:21 -0600

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From: [email-masked]
Date: Wed, 10 Mar 1999 10:48:33 +0530

Hi Davis,
    Thanks for your inputs.

In contrast to what you said, I think RAS signalling is must for all the
endpoints in any GK's zone. RAS signaling is not required for endpoints,
outside the zone. Now when GK receives a Setup message, it doesn't know
whether it is from its own zone or from outside. Before doing any further
checks, it needs to check that. And as I mentioned in my previous mails, to
do that, it needs to maintain a static databse of its zone. But there is no
mandatory field in Setup message,giving source info. So basic question is
how to perform this check.

regards,
Ritu.

_____________________________________________________________________
Ritu Gupta                                   |       email:
[email-masked]
Senior Software Engineer,       |                   [email-masked]
Hughes Software Systems,     |       phone: 91-80-2286390/91/92(W)
Banglore, Karnataka                  |                    91-80-3374075(H)
INDIA.                                            |       Fax    :
91-80-2286393
_____________________________________________________________________
Restlessness and discontent are the first necessities of progress.

"ronald h. davis" <[email-masked]> on 03/09/99 11:32:19 PM

To:   [email-masked]
cc:   [email-masked], [email-masked]
Subject:  Re: Handling of Setup message by Gatekeeper.

[email-masked] wrote:
               [scenarios deleted]
> In all these cases, gatekeeper will receive Setup message without
receiving
> ARQ message. So how can gatekeeper check whether ARQ is expected from the
> endpoint, which sent the Setup or not? No field in the Setup message seem
> to give this information. If gatekeeper doesn't check for this, that
means
> even the endpoints in its own zone can bypass gatekeeper for RAS
> signalling?
>
> Any help/information on this issue will be appreciated.
>
the gatekeeper is only responsible for arq/acf/arj with endpoints within
its zone.  all endpoints within the zone establish a ras channel (over
which these messages are sent) with their gatekeeper.
endpoints in other zones don't establish a ras channel with this
gatekeeper.  thus, when calls are received from outside of the zone
the recipient (be through the direct or gatekeeper routed call model)
has no idea how the calling endpoint came upon sending the setup
message.
this statement may be controversial but it is my opinion that h.323
is lan-oriented, so if you think of gatekeepers as administering
bandwidth allocation, &c for endpoints on different lans it would
be difficult for a gatekeeper to perform this administration for
a different lan.  and it would be even harder for a gatekeeper to
perform such administration over a wide area network consisting of
a number of zones.
this fact leads me to believe that the ras channel should be *optional*
for h.323 gatekeepers.  to abstract your scenarios further it is
possible that gatekeepers could act as application layer routers, in
which case they are terminating h.225 signalling and h.245 media control
channels for endpoints with which they have no ras channel.
--
  __  ______  __  / __/ |       lucent technologies, naperville il, usa
_/ (_(_) / (_(_/_/_(_/  .       [email-masked]
"if you ain't the lead dog, the scenery never changes"  -- edmund wilson

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