Nortel Networks NN43001-563 - Manual (Page 68)

68 System description
Recent releases of TM 3.1 that are properly configured, with all applicable
patches and the fix integrated, have the default for new systems set to 128
ms. This results in all new nodes being given the correct default value.
However, it will not change the value on systems that are already configured
unless the user deliberately changes the value.
IP Trunk 3.01 includes an enhancement to accommodate this issue. Since
a 32-ms ECAN tail delay is usually only provisioned "by default" and not
by deliberate user programming, the IP Trunk 3.01 application maps an
ECAN tail delay of 32 seconds to the corrected default of 128 ms. This
addresses the vast majority of users who want the optimum available ECAN
performance. However, a small number of users, for various reasons, may
want the 32-ms tail delay.
Users that can accept poorer echo performance and really want a 32 ms
delay can use a value of 8 ms, which the IP Trunk application maps to 32
ms. A delay of 8 ms is completely unacceptable to end users, so this does
not result in any loss of user capabilities. In addition, a value of 16 ms,
which is also unsatisfactory, is mapped to a delay of 64 ms, maintaining the
same two-to-one ratio with the next lower value in both the TM 3.1 and IP
Trunk environment. (In this case, the 8 ms value is half the 16 ms, and the
32 ms value is half the 64 ms value.)
Table 8 "Echo canceller tail delay mapping from OTM to IP Trunk 3.01"
(page 68)
shows the mapping between the delay value configured in TM
3.1 and the actual delay value used in IP Trunk 3.01. The actual configured
delay value can be displayed using the CLI command
itgCardShow . If
the TM 3.1 value is mapped, "Default - xxx" is displayed, where "xxx" is
the mapped value. If the TM 3.1 value is 64, 96, or 128 ms, "Value from
TM 3.1 - xxx" is displayed.
Table 8
Echo canceller tail delay mapping from TM 3.1 to IP Trunk 3.01
Provisioned in TM 3.1 (in ms) Value used by IP Trunk 3.01
8 32
16 64
32 (default value in IP Trunk 3.01 and
earlier) 128 (default value in IP Trunk 3.01)
64 64
96 96
128 (default value in IP Trunk 3.01) 128 (default value in IP Trunk 3.01)
Nortel Communication Server 1000
IP Trunk Fundamentals
NN43001-563 01.01 Standard
Release 5.0 30 May 2007
Copyright © 2007, Nortel Networks
.