3Com 10014299 manual Configure Lapb, By default, the Lapb modulus is Modulo

198CHAPTER 16: CONFIGURING LAPB AND X.25

Figure 61 Relations among LAPB, X.25 and X.25 switching

Inter-network protocol

X.25 switching

X.25

LAPB

Configure LAPB LAPB configuration includes:

■Configure the link protocol of the interface to LAPB

■Configure LAPB protocol parameters

1Configure the Link Layer Protocol of the Interface to LAPB Perform the following command in the interface view.

Table 229 Configure the link layer protocol of the interface to LAPB

Operation	Command
Configure the link layer protocol of the interface to	link-protocol lapb [ dte
LAPB	dce ] [ ip ]

If not specified, the working mode of LAPB is DTE by default.

2Configure LAPB Protocol Parameter

a Configure LAPB operating mode (also called modulo)

There are two LAPB modulus: Modulo 8 and Modulo128. Each data frame (I frame) is numbered by sequence, the number can be any from 0 to modulo minus 1, and the sequence number is selected periodically within the range of the modulo.

In the interface view, configure as follows:

Table 230 Configure LAPB frame numbering mode

Operation	Command
Configure LAPB frame numbering mode (also called	lapb modulo { 128 8 }
modulo)
By default, the LAPB modulus is Modulo 8.

bConfigure LAPB parameter K

The parameter K in the LAPB window represents the maximum number of I frames numbered in sequence that is to be identified by the DTE or DCE in any specified time.

In the interface view, configure as follows:

Table 231 Configure LAPB window parameter K

	Operation	Command
	Configure LAPB window parameter K	lapb window-size k-value
	Restore the default value of LAPB window parameter	undo lapb window-size
	K
By default, k is 7.
c Configure LAPB N1, N2