3Com 10014299 Configure Additional Parameters Datagram Transmission, X25 pvc pvc-number protocol

208CHAPTER 16: CONFIGURING LAPB AND X.25

process and it always exists. An address mapping will be created implicitly while a permanent virtual circuit is created.

To create/delete a permanent virtual circuit, perform the following tasks in interface view.

Table 247 Create/Delete permanent virtual circuit

Configure Additional

Parameters of X.25

Datagram Transmission

Operation	Command
Create a permanent virtual circuit	x25 pvc pvc-number protocol
	protocol-address x121-address
	x.121-address [ option ]
Delete a permanent virtual circuit	undo x25 pvc pvc-number

The format of this command shows that while a permanent virtual circuit is created, an address mapping is also created for it. Similarly, the protocol-addressand x.121-addressin the command also refer to the destination address. While creating a permanent virtual circuit, some attributes of the PVC can also be selected via the option. This [option] is a subset of [option] in the command "x25 map...... [option]".

For configuration example of permanent virtual circuit, refer to subsequent sections.

The Configuration additional parameters of X.25 datagram transmission includes:

■Specify the maximum idle time of SVC

■Specify the maximum number of SVCs that is associated with the same address mapping

■Specify the pre-acknowledgement of packet

■Configure X.25 user facility

■Set the length of virtual circuit queue

■Broadcast via X.25

■Restrict the use of address mapping

■Configure the interface with the standby center

The X.25 of the 3Com Router series allows adding some additional characteristics, including a series of optional user facilities stipulated in ITU-T Recommendation X.25.

This section shows how to configure such additional characteristics, including the options in the two commands of "x25 map ......" and "x25 pvc......". Please

select and configure these additional characteristics according to the actual needs, X.25 network structure and the services provided by service provider.

1Configure SVC maximum idle time

Specify a time period, and if SVC is idle within this period (no packet interaction), then X.25 of the 3Com Router series will automatically clear this SVC to avoid unnecessary expenses. Before the data packet is sent next time, this SVC will be reestablished. So the activation of this characteristic will not affect data transmission.

In the interface view, this task can be accomplished in two different ways. For details, refer to the table as follows.