Nortel ISDN Signaling Link, Описание, установка и эксплуатация

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Description Page 29 of 378
ITG Trunk 2.0 ISDN Signaling Link (ISL) Description, Installation and Operation
• Backup Leader
• D-channel IP gateway (DCHIP)
The ITG ISL Trunk card roles identify which systems are active
systems/standby systems and which are client systems. The Active Leader
has a Node IP address on the voice interface. This Node IP is an alias IP which
is added to the original IP address on the voice interface. Other machines in
the network use the Node IP to keep track of the Active Leader.
Each Meridian 1 is usually configured with the following:
• one ITG ISL Trunk card that acts as an Active Leader
• one ITG ISL Trunk card that acts as a Backup Leader
• at least one ITG ISL Trunk card that provides DCHIP functionality
• one or more ITG ISL Trunk cards identified as Followers.
In the MAT ITG application, the term Leader 0 refers to the ITG ISL Trunk
card initially configured to perform the role of the Active Leader. The term
Leader 1 refers to the ITG ISL Trunk card that is initially configured to
perform the role of Backup Leader. The Active Leader and Backup Leader
exchange the Node IP address when the Active Leader goes out-of-service.
The term Active Leader indicates the Leader 0 or the Leader 1 card that is
performing the Active Leader role.
Leader 0 or Leader 1 can have the Active Leader status. On system power-up,
Leader 0 normally functions as the Active Leader and Leader 1 as the Backup
Leader. At other times, the Leader card functions reverse with Leader 1
working as the Active Leader and Leader 0 working as the Backup Leader.
The Leader, Backup Leader, Follower, and DCHIP cards communicate
through their E-LAN connections.
Follower
A Follower card is an ITG ISL Trunk card which converts telephone signals
into data packets and data packets into telephone signals. Follower cards also
provide dialed number to IP address translation.