ARQ/ACF

[Tom-PT Taylor]

Sorry, Radhika, nowhere in this is a GK sending an ARQ to another GK

> -----Original Message-----
> From: Roy, Radhika R, ALTEC [SMTP:rrroy at ATT.COM]
> Sent: Friday, August 28, 1998 7:03 PM
> To:   ITU-SG16 at MAILBAG.INTEL.COM
> Subject:      Re: ARQ/ACF
>
> Hi Santo:
>
> Section 8.1.6.(3/27/98 - Contact Person G. Thom - Editor) - Thanks,
> Radhika
>
> 8.1.6 Optional Called Endpoint Signalling
> The procedures defined in 8.1.4 and 8.1.5 show that when a called endpoint
> is registered to a Gatekeeper, a Setup message is initially sent to the
> called endpoint from the calling endpoint or the calling endpoint's
> Gatekeeper. If the called endpoint's Gatekeeper wishes to use the
> Gatekeeper
> routed call model, it returns its own Call Signalling Channel Transport
> Address in the ACF. The called endpoint then uses the Facility message to
> redirect the call to the called endpoint's Gatekeeper's Call Signalling
> Transport Address. These procedures assume that the calling endpoint or
> calling endpoint's Gatekeeper only knows the called endpoints Call
> Signalling Channel Transport Address. This address may have been received
> in
> an LCF sent in response to an LRQ requesting the address of the called
> endpoint or it may be known through out of band methods.
> If the called endpoint's Gatekeeper desires a Gatekeeper routed call
> model,
> it may return its own Call Signalling Transport Address in the LCF. This
> will allow the calling endpoint or calling endpoints Gatekeeper to send
> the
> Setup message directly to the called endpoints Gatekeeper, thus
> eliminating
> the redirection process.
> An example of this scenario is shown in Figure 24/H.323. In this example,
> both endpoints are registered to different Gatekeepers, and both
> Gatekeepers
> choose to route the call signalling (similar to the case in Figure
> 23/H.323).  Endpoint 1 (calling endpoint) sends an ARQ (1) to Gatekeeper
> 1.
> Gatekeeper 1 multicasts an LRQ(2) to locate called Endpoint 2. Gatekeeper
> 2
> returns an LCF(3) with the Call Signalling Channel Transport Address of
> itself. Thus, Gatekeeper 1 will subsequently send a Setup (6) message to
> Gatekeeper 2's Call Signalling Channel Transport Address and Gatekeeper 2
> will send a Setup (8) message to Endpoint 2.  Endpoint 2 initiates the ARQ
> (9)/ACF (10) exchange with Gatekeeper 2. Endpoint 2 then responds to
> Gatekeeper 2 with the Connect (12) message which contains its H.245
> Control
> Channel Transport Address for use in H.245 signalling.  Gatekeeper 2 sends
> the Connect (13) message to Gatekeeper 1 which may contain the Endpoint 2
> H.245 Control Channel Transport Address, or a Gatekeeper 2 (MC) H.245
> Control Channel Transport Address, based on whether the Gatekeeper 2
> chooses
> to route the H.245 Control Channel or not.  Gatekeeper 1 sends the Connect
> (14) message to Endpoint 1 which may contain the H.245 Control Channel
> Transport Address sent by Gatekeeper 2, or a Gatekeeper 1 (MC) H.245
> Control
> Channel Transport Address, based on whether the Gatekeeper 1 chooses to
> route the H.245 Control Channel or not.
>
>  <<...>>
>
>
        [Taylor, Tom [CAR:B318-I:EXCH]]  <snip>