3Com 10014299 manual Configure

Configure X.25 199

N1 value represents the maximum number bits of I frame that DCE or DTE wants to receive from DTE or DCE.

N2 value represents the maximum number of times that DCE or DTE tries to successfully send a frame to DTE or DCE.

Table 232 Configure LAPB N1, N2

Operation	Command
Configure LAPB parameter N1	lapb max-frame n1-value
Restore the default value of LAPB parameter N1	undo lapb max-frame
Configure LAPB parameter N2	lapb retry n2-value
Restore the default value of LAPB parameter N2	undo lapb retry

By default, n1 is 12032, and n2 is 10.

dConfigure LAPB T1, T2, T3

LAPB T1, the retransmission timer (T1) determines how long a frame that is already sent, can remain unacknowledged before retransmission. The value of T1 should be larger than the maximum interval between sending a frame and receiving its response frame. Retransmission timer is started after sending the frame but if response is not received and timer is expired then frame will be retransmitted.

LAPB T2, the receiving timer (T2) determines when to send a confirmation frame to the opposite DCE (or DTE) before T1 expires (T2<T1).

LAPB T3, the idle channel timer, determines when to report the long-time idle channel state to the packet layer. The timer value must be larger than T1 in DCE (T3>T1). If T3 is 0, it indicates that the timer is not set.

Table 233 Configure LAPB system timer T1, T2, T3

Operation	Command
Configure LAPB system timer T1, T2, T3	lapb timer { t1 t1-value
	t2	t1-value t3 t3-value }
Restore the default value of LAPB system timer T1,	undo lapb timer{ t1 t2
T2, T3	t3	}

By default, T1 is 2000ms; T2 is 1000ms and T3 is 0ms.

Configure X.25	X.25 configuration includes:
	■	Configure X.25 interface
	■ Configure X.25 interface supplementary parameter
	■ Configure X.25 datagram transmission
	■ Configure the supplementary parameters of X.25 datagram transmission
	■ Configure X.25 sub interface
	■	Configure X.25 switching

■ Configure X.25 load balancing

Besides configuring X.25, appropriate modification to some LAPB parameters in certain cases can also optimize the performance of X.25.