Nortel 1000 Description, Installation And Operation Manual page 37

IP Trunk 3.01 (and later) supports Gatekeeper Registration and Admission
Signaling (RAS) and Call Admission Signaling. IP Trunk 3.01 (and later)
interworks with CS 1000S or CS 1000M, which fulfills the role of a
Gatekeeper. Using H.323 RAS, IP Trunk 3.01 (and later) uses RAS
Messaging to register with the Gatekeeper if provisioned to do so. IP Trunk
3.01 (and later) then processes calls by scanning its Directory Number (DN)
information. If the call is not resolved using the local Address Translation
Protocol Module (ATPM) and IP Trunk 3.01 (and later) is registered with a
Gatekeeper, then IP Trunk 3.01 (and later) routes the call to the Gatekeeper.
Administrators use OTM 2.1 (and later) to configure the IP address of a
CS 1000S or CS 1000M node with a capability of "CS 1000S" in the ATPM
dialing plan table. This enables the IP Trunk 3.01 (and later) node to directly
call the CS 1000S or CS 1000M node.
The IP Trunk 3.01 (and later) node is subordinate to the Gatekeeper for all
calls requiring the Gatekeeper. The IP Trunk 3.01 (and later) node registers
with the Gatekeeper according to H.323 protocol, requests admission, accepts
the reply according to H.323 protocol, and handles the call based on the
returned message from the Gatekeeper.
A CS 1000S or CS 1000M node consists of two components:
• Call Server – used for call control of CS 1000S or CS 1000M gateways
• Signaling Server – used for protocol analysis
The CS 1000S/CS 1000M Gatekeeper accepts the registration of multiple IP
trunk cards implicitly in a single RRQ. This means that all Follower cards are
registered at the same time as the Leader card, because the
CS 1000S/CS 1000M node returns an endpointIdentifier assigned by the
Gatekeeper to that node. Later, a request to establish a call to a
Gatekeeper-controlled endpoint receives in the response the
enpointIdentifier of the endpoints that was provided at registration.
Note: The CS 1000S/CS 1000M gateways interwork with the IP Trunk
3.01 (and later) gateway resident function which generates the
FACILITY redirect. The FACILITY redirect is used when calls
terminate at an IP Trunk 3.01 (and later) node. The CS 1000S/CS 1000M
gateways do not use this redirection themselves.
Overview of IP Trunk 3.01
IP Trunk Description, Installation, and Operation
Page 37 of 644