Avaya Communication Manager Administrator's Manual page 1771

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 illustrated 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 four (T1) or five (E1) fixed 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
may route to a different trunk group preference and be subject to another algorithm based on the
wideband options administered.
This same trunk or hunt algorithm, when offered any narrowband or N x DS0 call, attempts to preserve
idle quadrants by choosing a trunk(s) in a partially contaminated quadrant if one exists. If a partially
contaminated quadrant capable of carrying the call does not exist, then the call is placed on available
trunk(s) within an idle quadrant, thus contaminating the quadrant. Again, facilities are selected via the
trunk group's facility list and with PN preference, and a trunk(s) within a facility is selected based on the
direction 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 this algorithm
also attempts to preserve idle facilities. In other words, when offered a narrowband, H0, or N x DS0 call,
the algorithm 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).
Administrator's Guide for Avaya Communication Manager
November 2003
DS0s Comprising Each Channel
ISDN
Interface H11
23B + D -
24B (NFAS) 1-24
30B + D 1-15, 17-25
31B (NFAS) 1-15, 17-25
Feature Reference
Wideband Switching
H12
-
-
1-15, 17-31
1-15, 17-31
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