Lucent Technologies 8.2

DEFINITY ECS Release 8.2

Administrator’s Guide

555-233-506 Issue 1

April 2000

Managing data calls

429Wideband Switching

Note that on a T1 facility, a D-channel is not considered a busy tr unk and results in

a facility with a D-channel always being pa rtially 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 facility 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 algorit 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

shown in the following table). When offered any other call (o ther 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

scheme supports 4 (T1) or 5 (E1) starting points. The H0 algorithm searches for

an available quadrant within a facility based on the direction of trunk or hunt

administered. If the algorithm cannot find an available quadr ant within an y facilit y

allocated to this trunk group, then the call is blocked from using this trunk group.

Again, based on GRS administration, the call may route to a dif f er ent t run k group

preference and be subject to another algorithm based on the wideband options

administered.

Note that a D-channel is considered a busy trunk and results in the top most

quadrant of a T1, B-channels 19 to 24, always being partially contaminated. This

is not true for NFAS.

If this H0 optioned trunk group is also administered to support H11, H12, or N x

DS0, then the system also attempts to preserve idle facilities. In other w ords, when

offered a narrowband, H0, or N x DS0 call, the system searches

partially-contaminated facilities before it searches to idle facilities.

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