Nortel Networks NN43001-563 - Manual (Page 24)

24 Overview of IP Trunk 3.01
On startup, if the IP Trunk 3.01 (and later) Leader is provisioned to use a
Gatekeeper, it seeks out and locates the Gatekeeper using RAS signalling
and then registers with the Gatekeeper using an RRQ. As part of the
registration process, the IP Trunk 3.01 (and later) Leader registers using the
registration handling flag to determine how to proceed.
The Gatekeeper and IP Trunk 3.01 (and later) re-register on a regular basis,
based on the Time To Live (TTL) configured for the IP path.
The Gatekeeper is the final authority on the TTL values. The Gatekeeper
can override the provisioned value of IP Trunk 3.01 (and later) and require
the IP Trunk 3.01 (and later) gateway to change its TTL value to match that
required by the Gatekeeper.
Depending on the Gatekeeper type (for example, Gatekeepers other than
CS 1000M), if the Gatekeeper flag in the dial plan file indicates the need for
multiple IP Trunk 3.01 card IP addresses (flag value = 0), the RRQ includes
all IP addresses for the node. These additional IP addresses are reserved
exclusively for calls to the Gatekeeper. By sending all the IP addresses in
the RRQ, the Gatekeeper is able to determine the origin of the admission
requests. These addresses are used when the Gatekeeper considers
the endpointIdentifier sent to the gateway in the RRQ confirmation to
be insufficient to confirm that the Admission Request (ARQ) belongs to a
gateway registered with that Gatekeeper. The Gatekeeper rejects any ARQ
from an unknown end-point.
CS 1000M requires an endpointIdentifier match and does not care about
the IP addresses. Therefore, the Gatekeeper flag is unnecessary for CS
1000M.
On startup, the message flow between the IP trunk card serving as the IP
Trunk 3.01 (and later) Active Leader and the Gatekeeper is as follows:
1. Gatekeeper Request (GRQ) – From the Active Leader to the
Gatekeeper, using the provisioned Gatekeeper IP address. The Optivity
Telephony Manager (TM 3.1) configuration indicates where the IP
Trunk 3.01 (and later) node must look for its Gatekeeper, but this is
not necessarily the actual Gatekeeper address the node uses for call
processing.
Some Gatekeepers use a "virtual IP address" to screen the fact that
the Gatekeeper with which the gateway registers has internal standby
controllers. In this case, the request might go to a Gatekeeper server
that determines the correct virtual IP address. The Gatekeeper’s
internal Message Forwarding process sends the messages to the
current active Gatekeeper node.
CS 1000M do not require a Gatekeeper Request from IP Trunk 3.01
(and later); therefore, no Request or Confirm is sent.
Nortel Communication Server 1000
IP Trunk Fundamentals
NN43001-563 01.01 Standard
Release 5.0 30 May 2007
Copyright © 2007, Nortel Networks
.