Nortel Networks NN43001-563 - Manual (Page 102)

102 ITG engineering guidelines
supporting the other half of the Followers. This rule covers D-Channel
redundancy with two IP Trunk 3.01 (and later) routes per node.
3. Leader 0 with DCHIP but no voice ports configured supporting Leader 1
and all Followers. This rule covers very large nodes and networks with
multiple IP Trunk 3.01 (and later) routes per node.
4. Leader 0 with DCHIP and all voice ports configured supporting Leader 1
and all Followers. This configuration can only be used for smaller nodes
and networks that do not have a large call volume.
To set up an incoming voice or fax call, the Follower card must communicate
with the Follower card at the far end to set up and tear down the call.
However, the Leader card must assist the Follower card in obtaining the IP
address of the far end Follower card and provide network performance
statistics so that the Follower card can set up the call correctly. The Leader
card CPU real-time must be engineered to reserve enough capacity to
provide this call processing functionality.
Additionally, the DCHIP card sends and receives all D-channel messages
from the system to all Follower cards. In a multi-card node, the DCHIP
card CPU real-time must be engineered to reserve enough capacity to
successfully transmit and receive D-channel messages.
Card role
IP Trunk cards have various roles. Each role is affected by the amount of
traffic in varying degrees. The following card roles are listed in order from
the most impacted by call volume to the least affected by call volume:
DCHIP card role
Generally, the number of available voice ports on the IP trunk card having
the DCHIP card must be engineered as either the number of cards per
node and/or the traffic rate per node increase. Single card nodes are a
special case for DCHIP functionality, as the DCHIP traffic both originates
and terminates on the same card. This is the opposite of a multi-card node
configuration, where the DCHIP traffic originates and terminates across the
IP LAN. With IP Trunk 3.01 (and later), there is no additional work for the
DCHIP role whether the calls are Gatekeeper-routed or not.
Leader card role
The Leader card plays a role in all call termination as the owner of the Node
IP address and the resource (port) availability manager for the node. The
Leader card also maintains the functionality for QoS probing generation and
termination for the node. For this reason, the number of available voice
ports on the Leader card must be engineered inversely to the total number
of IP Trunk 3.01 (and later) nodes with QoS enabled in the IP Trunk 3.01
Nortel Communication Server 1000
IP Trunk Fundamentals
NN43001-563 01.01 Standard
Release 5.0 30 May 2007
Copyright © 2007, Nortel Networks
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