Lucent Technologies 8.2 User Manual

Page of 1707
DEFINITY ECS Release 8.2
Administrator’s Guide  
555-233-506  
Issue 1
April 2000
Managing data calls 
429
Wideband Switching 
15
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.
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.
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.
DS0s Comprising Each Channel
Facility
ISDN
Interface
H11
H12
T1
T1
23B + D
24B (NFAS)
-
1-24
-
-
E1
E1
30B + D
31B (NFAS)
1-15, 17-25
1-15, 17-25
1-15, 17-31
1-15, 17-31