Configuring X.25 Interface Supplementary Parameters - HPE FlexNetwork MSR Series Comware 5 Layer 2 - Wan Access Configuration Manual

Configuring X.25 interface supplementary parameters

Introduction to X.25 interface supplementary parameters
It is necessary to configure certain supplementary X.25 parameters in some special network
environments. The following sections are related to the following supplementary parameters.
•
X.25 layer 3 delay timer
X.25 protocol defines a series of timers to facilitate its procedure. After X.25 sends a control
message, if it does not receive the response before the timer expires, X.25 protocol will take
measures to handle this abnormal event.
timers.
Table 5 X.25 Layer 3 timer
Procedure name
Restart
Call
Reset
Clear
Register
T28 is a "Registration request sending" timer which is only defined on DTE for dynamically
requesting the network for optional services or stopping these services. Its default value is 300
seconds, which cannot be changed.
•
Attributes related to X.25 address
To establish an SVC with a call, X.25 address is needed, which adopts the address format
specified in ITU-T Recommendation X.121. An X.121 address is a string of 1 to 15 digits. Some
attributes related to X.121 address are as follows:
•
Alias of interface
When an X.25 call is forwarded across multiple networks, different networks will likely make
some modifications on the called address as needed, such as adding or deleting the prefix. In
such cases, the destination address of a call that reaches X.25 interface might be inconsistent
with X.121 address of the destination interface (because the destination address of this call is
modified within the network); still the interface should accept this call. For this purpose, one or
more alias names must be specified for this interface.
To meet the requirements of different networks, X.25 defines nine match types and their
relevant alias string formats, as shown in
Table 6 Alias match modes and meanings
Matching mode
free
free-ext
left
Table 5
Timer name
DTE side
T20
T21
T22
T23
T28
Table
Description
Free matching, the alias string is
in the form of 1234.
Extended free matching, in
which the alias string is in the
form of ...1234..
Left-most matching mode, in
which the alias string is in the
form of $1234.
318
lists the names and procedures of these
DCE side
T10
T11
T12
T13
N/A
6.
Example
"1234" will match 561234,
1234567 and 956123478, but
will not match 12354.
"...1234 .." will match
678123459, but will not match
68123459, 67812345 and
6781234591.
"$1234" will match 1234567 and
12346790, but will not match
3123478 and 123784.