Lucent Technologies 8.2

DEFINITY ECS Release 8.2

Administrator’s Guide

555-233-506 Issue 1

April 2000

Managing data calls

428Wideband Switching

Given this facility list concept, the algorithms have the ability to se arch for tru nks,

by facility, in an attempt to satisfy the bandwidth requirements of a given

wideband call. If one facility does not have enough a v ai lable b andwidth t o support

a given call, or it is not used for a given call due to the constrain ts pres ented i n the

following section, then the algorithm searches the next facility in the trunk group

for the required bandwidth (if there is more th an one facility in the trunk group).

In addition to searching for channels based on facilities and required bandwidth,

Port Network (PN) preferential trunk routing is also employed. This PN routing

applies within each algorithm at a higher priority than the constraints put on the

algorithm by the parameters listed later in this section. In short, all facilities that

reside on the same PN as the originating endpoint are searched in an attempt to

satisfy the bandwidth of a given call, prior to searching any facilities on another

PN.

Direction of trunk/hunting within facilities

You can tell the system to search for available channels in either ascending or

descending order. These options help you reduce glare on the channels because

the system can search for channels in the opposite direction to that used by the

network. If an ISDN trunk group is not optioned for wideband, then a cyclical

trunk hunt based on the administration of trunks within the trunk group is still

available.

H11

When a trunk group is administered to support H11, the algorithm to satisfy a call

requiring 1,536 Kbps of bandwidth uses a fixed allocation scheme. That is, the

algorithm searches for an available facility using the following facility-specific

channel definitions:

■T1: H11 can only be carried on a facility without a D-channel being

signaled in an NFAS arrangement (B-channels 1-24 are used).

■E1: Although the 1,536 Kbps bandwidth could be satisfied using a number

of fixed starting points (for example, 1, 2, 3, and so forth), the only fixed

starting point being supported is 1. Hence, B-channels 1-15 and 177-25

always are used to carry an H11 call on an E1 facility.

If the algorithm cannot find an available facility within the trunk that meets these

constraints, then the call is blocked from using this trunk group. In this case, the

call may be routed to a different trunk group preference via Generalized Route

Selection (GRS), at which time, based on the wideband options administered on

that trunk group, the call would be subject to another hunt algorithm (that is, either

the same H11 algorithm or perhaps an N x DS0 algorithm described in a later

paragraph).