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

290 C 14: X.25
HAPTER
Configuring X.25
Interface Supplementary
Parameters
LAPB C
AND ONFIGURATION
To do...
Set the modulo
Set the sizes of VC input
window and output
window
Set the maximum sizes
for input and output
packets on the interface
It is necessary to configure certain supplementary X.25 parameters in some special
network environments. The section is related to these supplementary parameters.
X.25 layer 3 delay timer
X.25 protocol defines a series of timers to facilitate its procedure. After X.25 sends
a control message, if it does not receive the response before the timeout of the
corresponding timer, X.25 protocol will take corresponding measure to handle this
abnormal event. The names and corresponding procedures of these timers are
shown in the following table.
Table 5 X.25 Layer 3 timer
Procedure name
Restart
Call
Reset
Clear
Register
T28 is "Registration request sending" timer that is only defined on DTE for
dynamically requesting the network for optional services or stopping these
services. Its default value is 300 seconds, which cannot be changed.
Attributes related to X.25 address
To establish a SVC with a call, X.25 address is needed, which adopts the address
format specified in ITU-T Recommendation X.121. An X.121 address is a string of
0 to 15 digits. Some attributes related to X.121 address are as follows:
1 Alias of interface
When an X.25 call is forwarded across multiple networks, different networks will
likely make some modifications on the called address as needed, such as adding or
deleting the prefix. In such cases, the destination address of a call that reaches
X.25 interface may be inconsistent with X.121 address of the destination interface
(because the destination address of this call is modified within the network), still
the interface should accept this call. For this purpose, one or more alias names
must be specified for this interface.
Use the command...
x25 modulo { 8 | 128 }
x25 window-size
input-window-size
output-window-size
x25 packet-size input-packet
output-packet
Timer name
DTE side
T20
T21
T22
T23
T28
Remarks
Optional
Defaults to 8
Optional
By default, input-window-size is 2
and output-window-size is 2
Optional
By default, input-packet is 128
bytes and output-packet is 128
bytes
DCE side
T10
T11
T12
T13
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