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6620-3201
4.59 Confi gure
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PPP
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PPP n
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PPP/IP Over X25
Westermo routers can optionally support transmission of TCP/IP packets encapsulated in X.25. This
feature allows the ISDN D-channel to be used as an “always on” connection providing a permanent,
low speed Internet Protocol pipe between two Local Area Networks.
Using the Web Page(s)
These parameters are used when con
fi
guring PPP or IP over X.25.
Calling NUA:
This speci
fi
es the calling X.25 address to be used when using PPP or IP over X.25.
Default packet size:
This speci
fi
es the default X.25 packet size to use.
IP over X25 mode:
When set to “On”, this causes the unit to route IP data over X.25. Otherwise, PPP over X.25 is used.
Layer 2 interface:
This parameter is used to select whether the PPP instance will use B or D-channel X.25. If “None” is
speci
fi
ed, then PPP/IP over X.25 mode is disabled.
Layer 2 interface #:
This parameter speci
fi
es which LAPB or LAPD instance to use for the relevant PPP instance.
LCN:
The LCN parameter is the value of the
fi
rst LCN that will be assigned for outgoing X.25 CALLs. The
default is 1027.
LCN direction:
This parameter determines whether the LCN used for outgoing X.25 calls is incremented or
decremented from the starting value when multiple X.25 instances share one layer 2 (LAPB or LAPD),
connection. The default is “Down” and LCN’s are decremented, i.e. if the
fi
rst CALL uses 1024, the
next will use 1023, etc. Setting the parameter to “Up” will cause the LCN to be incremented from the
start value.
Restart delay (ms):
When the
Restarts
parameter is set to “On” the value speci
fi
ed in the Restart
delay dialog box determines the length of time in milliseconds that the unit will wait before issuing a
Restart packet. The default value is 2000 giving a delay of 2 seconds.
Restarts:
It is normally possible to make X.28 CALLs immediately following the initial SABM, UA exchange. In
some cases however, the X.25 network may require an X.25 RESTART before it will accept
X.25 CALLs. The correct mode to select depends upon the particular X.25 service to which you
subscribe.
The default value is “On”. This means that the unit will issue X.25 RESTART packets. To prevent
the unit from issuing RESTART packets set this parameter to “Off”.
