Lucent Technologies 8.2

DEFINITY ECS Release 8.2

Administrator’s Guide

555-233-506 Issue 1

April 2000

Features and technical reference

1595Wideband Switching

If the algorithm cannot find an available facil it y wi thi n t he t r unk group that meets

these constraints, then the call is blocked from using this trunk group. In this c ase,

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).

This same hunt algorithm, when offered any other call (other than a 1,920-kbps

call) attempts to preserve idle facilities by selecting trunk(s) in a partially

contaminated facility if one exists. If the ban dwidth required by this call cannot be

satisfied by any partially contaminated faci lity, then the call is placed on av ai la ble

trunk(s) within an idle facility, thus contaminating the facility. Again, facilities are

selected via the trunk group’s facility list and with PN preference, and trunk(s)

within a facility are selected based on the direction of channel search

administered. Note that on a T1 facility, a D-channel is not considered a busy

trunk and results in a facility with a D-channel always being partially

contaminated. On an E1 facility, however, a D-channel is not considered a busy

trunk because H11 and H12 calls may still be placed on that facility; an E1 facilit y

with a D-channel and idle B-channels is considered an idle facility.

H12

Since H12 is 1,920 Kbps which is comprised of 30 B-channels, a 1,920-kbps call

can only be carried on an E1 facility. As with H11, the hunt al gorit hm uses a f ix e d

allocation scheme with channel 1 being the fixed starting point. Hence, an H12

call always is carried on B-channels 1 to 15 and 17 to 31 on an E1 facility (as

illustrated in the following table). When offered any other c al l (other than a

1,536-kbps call), the algorithm behaves as it does when H11 is optioned.

When a trunk group is administered to support H0, the algorithm to satisfy a call

requiring 384 Kbps of bandwidth also uses a fixed allocation scheme. Unlike the

H11 fixed scheme which only supports a single fixed starting point, the H0 fixed

DS0s Comprising Each Channel

Facility ISDN

Interface H11 H12

23B + D

24B (NFAS)

1-24

30B + D

31B (NFAS)

1-15, 17-25

1-15, 17-31