3com MSR 20-20 참조 매뉴얼

tcp peer ip: 10.1.1.1, peer port: 1998

tcp local ip: 10.1.1.2, local port: 1024

socket keepalive period: 5, keepalive tries: 3

come interface name: Serial1/0-10.1.1.1-1024

go interface name: Serial1/0 

lapb max-frame n1-value

Interface view

n1-value: N1 value of the LAPB parameter in bits, in the range 1096 to 12104. It is 
the maximum value of a frame expected from the DTE or DCE, 8 times the value 
of MTU plus the protocol header.

Use the lapb max-frame command to configure the LAPB N1 parameter.

Use the undo lapb max-frame command to restore the default.

The default value of N1 is calculated according to the MTU, upper layer protocol 
and modulo, as shows below:

The default value of N1 varies with MTU and modulo.

For example, upon system initialization, the upper layer protocol is IP, modulo 8 
and MTU 1500, so the default value of N1 is (1500+4)*8 = 12032. If the modulo 
is set to 128, then the default value of N1 is (1500+5)*8 = 12040. You can use the 
undo lapb max-frame command to restore the new default. For the same 
reason, N1 changes with the change of MTU.

# Set the LAPB N1 parameter to 1160 on Serial 2/0.

<Sysname> system-view

[Sysname] interface serial 2/0

[Sysname-Serial2/0] lapb max-frame 1160 

Table 64   Difference between N1 and MTU (in bytes) versus upper layer protocol and 
modulo

IP/IPX 8 

4 

IP/IPX 128  5 

Multiprotocol 8 

6 

Multiprotocol 128 

7 

X.25 8 

7 

X.25 128  8