Configuring X.25; Configuring X.25 Interface Parameters - 3Com MSR 50 Series Configuration Manual

286 C 14: X.25
HAPTER

Configuring X.25

Configuring X.25
Interface Parameters
LAPB C
AND ONFIGURATION
To do...
Enter system view
Enter interface view
Configure link layer
protocol as LAPB
Configure the modulo
Configure LAPB
window parameter K
Configure LAPB
parameter N1
Configure LAPB
parameter N2
Configure the system
timers T1, T2 and T3 in
LAPB
X.121 address
If the device is used for X.25 switching, this task can be skipped. If it is connected
to X.25 public packet network, you must set an X.121 address for the connected
X.25 interface according to the requirements of the ISP. As defined in ITU-T
recommendation X.121, an X.121 address is a string of 1 to 15 numbers.
X.25 operating mode
Layer 3 of X.25 supported by your device can work in either DTE mode, or in DCE
mode. The format of the datagram is alternative, either IETF or nonstandard.
Note that an X.25 public packet switching network requires the device to access
the network as DTE and to be encapsulated with the IETF format generally.
Therefore, the operating mode of X.25 should be DTE and the encapsulation
format should be IETF. When two routers are connected back to back through
serial interfaces, ensure that they are using the same encapsulation format and are
respectively working as the DTE and DCE.
X.25 virtual circuit range
The X.25 protocol can create multiple logical virtual connections over a physical
link between DTE and DCE. These virtual connections are called Virtual Circuits
(VCs) or Logic-Channels (LCs). Up to 4095 virtual circuits can be established by
Use the command...
system-view
interface interface-type
interface-number
link-protocol lapb [ dce |
dte ] [ ip | multi-protocol ]
lapb modulo { 8 | 128 }
lapb window-size k-value
lapb max-frame n1-value
lapb retry n2-value
lapb timer { t1 t1-value | t2
t2-value | t3 t3-value }
Remarks
-
-
Required
By default, the link layer protocol is
PPP. When LAPB is configured, the
interface works as DTE with upper
layer as IP.
Optional
Defaults to 8
Optional
Defaults to 7
Optional
The default N1 is calculated
according to the MTU, upper layer
and modulus value.
Optional
Defaults to 10
Optional
By default:
T1 is 3000 milliseconds
■
T2 is 1500 milliseconds
■
T3 is 0 second
■