Nortel Networks NN43001-563 - Manual (Page 41)

IP trunk card description 41
In a multi-card IP Trunk 3.01 (and later) node, the Active Leader is busier
than the Follower cards. As a result, the channels on the Follower cards
are used first. Only after most of the channels on the Follower cards and
Backup Leader card are in use does the Active Leader card assign an
incoming call to itself.
After a channel on a card has been selected, the Active Leader sends a
message to the selected IP trunk card telling it to reserve a channel for the
new call. The Active Leader redirects the call to the selected IP trunk card.
All subsequent messages are sent directly from the remote VoIP gateway
node to the selected card.
Backup Leader
The Backup Leader card steps in when the Leader is out-of-service. This
minimizes service interruptions.
D-channel IP gateway
The ITG-Pentium 24-port or Media Card 32-port trunk card with D-channel
IP gateway (DCHIP) functionality (DCHIP card) is connected by the RS-422
cable to the Multi-purpose Serial Data Link (MSDL) card on the Meridian
1/CS 1000M Large Systems. It connects to the SDI/DCH Card on Small
Systems. The DCHIP Card is equipped with a DCH PC Card. The DCH PC
Card provides the RS-422 and LAPD functionality that is required for the
D-channel (DCH) interface to the system. The DCHIP Card is the network
side of the system ISL D-channel connection. The card is a tandem node in
the switch network, providing a single-to-multi-point interface between the
Meridian 1/CS 1000M and the IP Trunk 3.01 (and later) network. See
Figure
5 "IP Trunk 3.01 (and later) architecture" (page 42) .
Nortel Communication Server 1000
IP Trunk Fundamentals
NN43001-563 01.01 Standard
Release 5.0 30 May 2007
Copyright © 2007, Nortel Networks
.