Avaya Communication Manager Administrator's Manual page 466

Managing Data Calls
Wideband Switching
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).
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 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 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 may route to a
different trunk group preference and be subject to another algorithm based on the wideband options
administered.
466
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
Administrator's Guide for Avaya Communication Manager
H12
-
-
1-15, 17-31
1-15, 17-31
November 2003