Avaya Communication Manager Administrator's Manual page 553

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 algorithm uses a fixed 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
(other than a 1,536-kbps call), the algorithm behaves as it does when H11 is optioned.
Facility
T1
T1
E1
E1
H0
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 quadrant within
any facility allocated to this trunk group, then the call is blocked from using this trunk group.
Again, based on GRS administration, the call might route to a different trunk 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 words, when offered a narrowband, H0,
or N x DS0 call, the system searches partially-contaminated facilities before it searches to idle
facilities.
N x DS0
For the N x DS0 multi-rate service, a trunk group parameter determines whether a floating or a
flexible trunk allocation scheme is to be used. The algorithm to satisfy an N x DS0 call is either
floating or flexible.
Floating (Contiguous) — In the floating scheme, an N x DS0 call is placed on a contiguous
●
group of B-channels large enough to satisfy the requested bandwidth without any
constraint being put on the starting channel (that is, no fixed starting point trunk).
DS0s Comprising Each
Channel
ISDN H11
Interface
23B + D -
24B (NFAS) 1-24
30B + D 1-15, 17-25
31B (NFAS) 1-15, 17-25
Wideband Switching
H12
-
-
1-15, 17-31
1-15, 17-31
Issue 2.1 May 2006 553