3Com 10014299 manual Set X.25 layer 3 timer delay

204CHAPTER 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.

1Configure 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

	Timer name
Procedure name	DTE side	DCE side
Restart	T20	T10
Call	T21	T11
Restore	T22	T12
Clear	T23	T13
Register	T28

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

Operation		Command
Set the timer delay value of restart procedure		x25	timer tx0 seconds
Default value (second): DTE: 180	DCE: 60
Cancel the set timer delay value of restart procedure		undo x25 timer tx0
Set the timer delay value of call procedure		x25	timer tx1 seconds
Default value (second): DTE: 200	DCE: 180
Cancel the set timer delay value of call procedure		undo x25 timer tx1
Set the timer delay value of restore procedure		x25	timer tx2 seconds
Default value (second): DTE: 180	DCE: 60
Cancel the set timer delay value of restore procedure		undo x25 timer tx2
Set the timer delay value of clearing procedure		x25	timer tx3 seconds
Default value (second): DTE: 180	DCE: 60
Cancel the set timer delay value of clearing procedure		undo x25 timer tx3

2Configure 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