Westermo MR Series - Manual (Page 168)

168 6622-3201
Web Interface and Command Line Reference Guide www.westermo.com
Confi gure > ISDN LAPD > LAPD n 4.53
Link Access Protocol D (LAPD) is the protocol used for ISDN D-channel signalling and call set up.
Using the Web Page(s)
The Configure > ISDN LAPD folder expands to list separate pages for the LAPD0, LAPD1 and
LAPD2 instances. LAPD2 is normally reserved for ISDN call control. LAPD0 and LAPD1 can be
used as required for SAPI16 traffic, i.e. D-channel X.25. The configuration pages allow you to set the
following parameters for each instance.
Enabled:
Setting this parameter to No will disable the LAPD instance. This may be necessary if you have
an installation where two or more units are connected to the same ISDN “S” bus. In this case,
only one of the units may be configured for D-channel X.25 on TEI1, SAPI16. On each of the
other units you must disable any LAPD instance for which the TEI is set to 1 in order to pre-
vent it from responding to X.25 traffic on that TEI that is actually destined for another unit.
DTE/DCE mode:
When the DTE/DCE mode parameter is set to DTE, the unit will behave as a DTE. This is the
default value and should not be changed for normal operation across the ISDN network. If your
application involves using two units back-to-back, one of the units should have the DTE mode
value set to DCE.
Keep active:
When this parameter is set to “Yes”, the unit will try to reactivate a D-channel connection after
dis connection by the network by transmitting SABME frames. If it is unable to reactivate the
connec tion after retrying the number of times specified by the N400 counter, it will wait for 1
minute before repeating the retry sequence.
If this parameter is set to “No”, the unit will not attempt to reactivate a D-channel link follow-
ing deactivation by the network.
Reactivate secs:
This parameter specifies the number of seconds a deactivation has to be present before the
LAPD instance will try to reactivate itself.
N400 counter:
This is the standard LAPB/LAPD retry counter. The default value is 3 and it should not normally
be necessary to change this.
RR timer (ms):
This is a standard LAPB/LAPD “Receiver Ready” timer. The default value is 10,000ms (10 sec-
onds) and it should not normally be necessary to change this.
Deactivation:
This parameter can be set to “Active” or “Passive”. When set to “Passive”, the unit will not
deacti vate a LAPD session when an X.25 PAD session is terminated using the log command. To
enable automatic deactivation of a LAPD session the option should be set to “Active”.
T1 timer (ms):
This is the standard LAPB/LAPD timer. The default value is 1000 milliseconds (1 second) and it
should not normally be necessary to change this.
T200 timer (ms):
This is the standard LAPB/LAPD re-transmit timer in milliseconds. The default value is 1000
milli seconds (1 second) and it should not normally be necessary to change this.