Multi-Tech Systems MVP-3010, MVP-2400, MVP-2410 manual 485

MultiVOIP User Guide Embedded Gatekeeper

Summary of

H.323 RAS* Messages (Registration, Admission, & Status)

of the H.225 Call Signaling Protocol

In a gatekeeper-controlled H.323 network, when call is made, the RAS channel between gatekeeper and endpoint is the first logical channel opened.

Admission Control	With an ARQ, an endpoint asks to participate
Messages	in a phone call. The gatekeeper can either
	grant the request (by sending an ACF
	message )
	or deny the request
	(by sending an ARJ message). When
	admission is granted, the endpoints
	participating in the call can exchange (H.225)
	call signaling messages directly between
	themselves.
	When the call is done, each endpoint, in turn,
	requests disengagement (DRQ) and is
	granted disengagement (DCF) by the
	gatekeeper.
ARQ	Admission Request.
ACF	Admission Confirmation.
ARJ	Admission Rejection.
DRQ	Disengagement Request.
DCF	Disengagement Confirmation.
Bandwidth Control	With a BRQ, an endpoint requests a certain
Messages	amount of digital bandwidth for a call.
	If the gatekeeper grants the request,
	it returns a BCF message.
	If the gatekeeper denies the request,
	it returns a BRJ message, typically because all
	allocated data channels are in use.
	If a bandwidth request is rejected, it is possible
	for a call to be conducted
BRQ	Bandwidth Request
BCF	Bandwidth Confirmation
BRJ	Bandwidth Rejection

*RAS in H.323 has nothing to do with the Remote Access Service that is used in ordinary TCP/IP networks.

485