Operation Manual

Reserving B Channels
NT/MPRI – 4 Special NT/MPRI Settings 70
Controller Settings
1. Make sure that the DSS1 driver for the ISDN-Controller to be used
by the leased line is installed.
2. Use the “Configuration / Server Settings / ISDN- and ADSL-Con-
trollers” menu command in the NT/MPRI Manager to select the
ISDN-Controller intended for the leased line.
3. Activate the “Leased line” option and select from the list the line
type “Digital 64S2 (2*64K)”.
4. Reserve the first and second B channels for the newly created di-
al-up connection and save your settings.
5. Select an additional ISDN-Controller from the “Configuration /
Server Settings / ISDN- and ADSL-Controllers” menu in the
NT/MPRI Manager and activate the option “Primary-rate Access”.
Save your settings.
Configuring a Dynamic Leased Line at the Remote Site
Now configure the dynamic leased line at the remote site in exactly the
same way as you did for the local site.
4.3 Reserving B Channels
The B channels of the ISDN-Controllers used by the NT/MPRI are
grouped in a pool and shared among all call destinations. This makes
for extreme flexibility and allows optimum utilization of the available
channels. The connection setup is also independent of specific ISDN B
channels. ISDN leased lines and ADSL connections are exceptions to
this, as their call destination settings link them to a certain ISDN-Con-
troller and to a certain B channel/time slot.
At any given time there may be more logical ISDN connections to re-
mote destinations than there are ISDN B channels available. This is
possible because the inactivity timeout automatically clears down idle
physical ISDN connections, freeing the B channels they occupied in the
NT/MPRI for use by other call destinations. The physical connection is
restored as soon as packets are requested from or queued for the re-
mote system.
If the majority of the call destinations have been configured to main-
tain a logical ISDN connection after an inactivity timeout, then the sys-
tem administrator must make sure that enough B channels are always
available (clear logical connection later then physical or never).
ntmpri-e.book Seite 70 Donnerstag, 28. Februar 2002 11:26 11