User manual

7 LAPB and X.25 configuration
Nortel Secure Router 8000 Series
Configuration -WAN Access
7-16 Nortel Networks Inc. Issue 5.3 (
30 March 2009)
Figure 7-7 X.25 channel division
1
LTC
LIC
HTC
HIC
LOC
HOC
4095
PVC range
Incoming-only channel range
unused
Two-way channel range
unused
Outgoing-only channel range
unused
1
LTC
LIC
HTC
HIC
LOC
HOC
4095
PVC range
Incoming-only channel range
unused
Two-way channel range
unused
Outgoing-only channel range
unused
For the meanings of these six parameters, refer to Table 7-1.
Table 7-1 Description of X.25 channel range delimitation parameters
Parameter Description
LIC Lowest Incoming-only Channel
HIC Highest Incoming-only Channel
LTC Lowest Two-way Channel
HTC Highest Two-way Channel
LOC Lowest Outgoing-only Channel
HOC Highest Outgoing-only Channel
Each range (except PVC ranges, it is 1 to (lic-1)) is defined by two parameters respectively
working as upper limit and lower limit. The parameters are in the range of 1 to 4095
(including 1 and 4095). The parameters are correct only if the following conditions are met:
In strict ascending order, i.e. 1 lic hic < ltc htc < loc hoc 4095.
If the upper limit (or lower limit) of a range is 0, then the lower limit (or upper limit)
shall also be 0, (which indicates this range is disabled to use).
Note the following points:
On the two sides (DTE and DCE) of a physical connection, these six parameters of
X.25 must be symmetric, as different settings at the two sides may result in an
improper procedure and cause transmission failures.
You should first set the range of the unidirectional call in channel, then set the range
of bidirectional call-in channel, and finally set the range of unidirectional call-out
channel.
In the configuration process, you should determine to implement the correct settings
of parameters. (Pay attention to the default settings of each parameter on the basis of
assuring an ascending order.)