Description Page 33 of 378
ITG Trunk 2.0 ISDN Signaling Link (ISL) Description, Installation and Operation
Card combinations
The Leader and DCHIP, or Follower and DCHIP, functions can reside on a
single card or multiple cards. If a Follower card is equipped with a DCH PC
card, it can function as a DCHIP ITG Trunk card. As a ITG Trunk node
becomes larger with more trunk traffic, loa d balan cing s hould be configu red.
When load balancing is required, the Leader and DCHIP functionality are
placed on separate cards which are assigned the least call traffic. For the
largest ITG Trunk nodes and networks, the Leader and DCHIP cards can be
partially configured with trunk ports or have no trunk ports at all.
An example configuration that allows for redundancy and backup is the
following:
•Card 1: Leader and DCHIP #1
•Card 2: Backup Leader and DCHIP #2
•Card 3: Follower #1 – 24 trunks connected with DCHIP #1
•Card 4: Follower #2 – 24 trunks connected with DCHIP #2
To support more trunks, more DCHs can be added. Each DCHIP card can
support a maximum of 15 NT0961AA 24-Port Follower cards. This limit is
due to the maximum limit of 382 trunks in an ISL route.
Note: Each DCHIP controls a separate group of Follower cards. If a
DCHIP fails, its associ at ed Foll o wer s ar e rem ove d fr om ser vic e as wel l.
For very large nodes, it is recommended that Follower cards be spread
across multiple DCHIPs, in order to provide so me resilienc y by allowing
the ITG node to continue handling calls if one DCHIP fails.
A DCHIP card and all of the ITG ISL Trunk cards connected with it belong
to one Leader card. This means that the cards also belong to a single
customer. The group of ITG ISL Trunk cards connected with one Leader is
referred to as an ITG Node. If a single Meridian 1 system has multiple
customers requiring IP trunk connectivi ty, a sepa rate ITG node is require d for
each customer. Multiple DCHIPs can be configured for each node.
Note: All DCHIPs in an ITG node must be configured with the same
DCH protocol. If the user wants to use multiple DCH prot ocols , the user
must configure multiple ITG nodes.