Nortel 1000 Description, Installation And Operation Manual page 57

The Leader, Backup Leader, Follower, and DCHIP cards communicate
through their ELAN subnet connections. For more information, see "Internet
Protocols and ports used by IP Trunk 3.01 (and later)" on
Follower
A Follower card is an ITG-Pentium 24-port trunk card and/or Media Card
32-port trunk card which converts telephone signals into data packets and
data packets into telephone signals. For outgoing calls, Follower cards
provide dialed number-to-IP address translation.
Active Leader
The Active Leader card is an IP trunk card that acts as a point of contact for
all other Meridian 1/CS 1000M systems in the network.
The Active Leader card is responsible for the following:
• distributing incoming H.323 calls to each registered Follower card in its
node and balancing load among the registered cards for incoming IP calls
• IP addresses for other cards in its node (see "Interactions among card
functions" on page
• serving as a time server for all IP trunk cards in its node
• performing network monitoring for outgoing calls in its node
• voice processing
All calls from a remote VoIP gateway node are first presented to the Active
Leader card. The Leader card maintains a resource table of all the IP trunk
cards in its node. The Active Leader card consults its internal IP trunk card
resource table to determine which card has the most idle channels and is the
least busy. Based on that information, the Active Leader card selects the card
to receive the new call.
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.
System description
62)
IP Trunk Description, Installation, and Operation
Page 57 of 644
page 174.