Filter
Top Products
204 CHAPTER 16: CONFIGURING LAPB AND X.25
■ Prohibit the restart of X.25 layer 3
It is necessary to configure certain supplementary X.25 parameters in some special
network environments.
1 Configure the delay of X.25 layer 3 timer
X.25 protocol defines a series of timers to facilitate its procedure. After X.25 sends
a control packet, if it does not receive the response before the timeout of the
corresponding timer, X.25 protocol will take corresponding measure to handle this
abnormal event. The names and corresponding procedures of these timers are
shown in the following table.
Table 240 X.25 layer 3 timer
In the table, T28 is the timer of “sending register request”, and is only defined at
the DTE side. It is used to dynamically apply to stop the selective services in the
network. Its reference value is 300 seconds, and cannot be modified. Perform the
following tasks in the interface view.
Table 241 Set X.25 layer 3 timer delay
2 Configure the attribute related to X.25 address
■ To establish a SVC with a call, X.25 address is needed, which adopts the
address format specified in ITU-T Recommendation X.121. X.121 address is a
character string consists of the Arabic numerals from 0 to 9, and it is of 0 to 15
characters.
■ Configure an alias for the interface
When an X.25 call is forwarded across the network, different networks will be
likely to make some modifications on the called address according to their own
needs, such as adding or deleting the prefix. In such cases, the destination address
Procedure name
Timer name
DTE side DCE side
Restart T20 T10
Call T21 T11
Restore T22 T12
Clear T23 T13
Register T28
Operation Command
Set the timer delay value of restart procedure
Default value (second): DTE: 180 DCE: 60
x25 timer tx0 seconds
Cancel the set timer delay value of restart procedure undo x25 timer tx0
Set the timer delay value of call procedure
Default value (second): DTE: 200 DCE: 180
x25 timer tx1 seconds
Cancel the set timer delay value of call procedure undo x25 timer tx1
Set the timer delay value of restore procedure
Default value (second): DTE: 180 DCE: 60
x25 timer tx2 seconds
Cancel the set timer delay value of restore procedure undo x25 timer tx2
Set the timer delay value of clearing procedure
Default value (second): DTE: 180 DCE: 60
x25 timer tx3 seconds
Cancel the set timer delay value of clearing procedure undo x25 timer tx3