Placement Of Nodes; Tie Trunk Routes; Network Call Routing - Avaya Communication Server 1000 Series Reference

Transmission planning

Placement of nodes

The first task is to choose locations for node switches. The following transmission factors
should be considered:
• Locate the node near a telco toll switching center to minimize the loop plant and short-
haul facilities between the node and long-haul facilities.
• Locate the node near the middle of its cluster of main circuit switches so most main-to-
node facilities fall in the short-haul category.
• If earth satellite facilities are used extensively, locate nodes near the earth station
facilities.
Once the nodes are designated, the remaining circuit switches are designated as main,
satellite, or tributary switches. All switches that have direct trunk groups to a node are main
circuit switches. Those switches that access a node by the main circuit switch are satellite or
tributary switches, depending on whether or not they have incoming Central Office Trunks
(COTs).

TIE trunk routes

Each pair of nodes in the network represents a potential TIE Trunk route. Traffic considerations
and tariffs determine how many routes are equipped and how many trunks are required for
each route. In general, the objectives of lowest cost and best transmission both dictate that
the number of tandem trunks required to establish any connection be kept to a minimum. Thus,
direct trunk routes should be established wherever practical.
Direct trunk routes represent a radical departure from Tandem TIE Trunk Networks (TTTNs).
For TTTNs, routing is usually organized into major trunk route highways with feeder routes.
This structure is efficient when alternate routing is not permitted, as with TTTNs, but it is not
efficient when alternate routing is supported, as with ESNs. Thus, converting a large TTTN to
an ESN can have significant impact on permitted routing.

Network call routing

Plan direct and alternate routes for routing calls so transmission can be evaluated on each
route and appropriate controls can be established on individual trunks.
table (maximum number of node-to-node routes)
36 Electronic Switched Network Reference — Signaling and Transmission
on page 37 gives the maximum number of
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Table 3: Route count
August 2011