Vocality V100 Technical Manual page 106

C H A P T E R 3 C O N F I G U R I N G V 1 0 0
The card provides the V100 with a dual 64K bearer interface, either of which may be used as a permanent
connection or dialled up in response to bandwidth requests from any tributaries that are routed over it.
To use the ISDN interface as a 64K backup service to another aggregate, it should be specified as a
secondary route to a normally available primary aggregate (the corresponding unit must, of course, also
have an ISDN Link Interface fitted). If the primary route fails, all connections are then re-routed via the
ISDN interface, which will automatically dial the stored destination number.
This principle may be extended to provide top-up bandwidth on a temporary basis, simply by overbooking
bandwidth on the primary route with the ISDN interface specified as the secondary route. Then, when a
connection cannot be made over the primary route through congestion, the ISDN interface will
automatically be used. The ISDN call will be maintained until all re-routed connections are closed, even if
the primary route becomes free. Next time, the primary route will be used as normal.
LINK MODE
In normal operation the card is configured to Dial On Demand, in which case the ISDN link will be dialled
when the first request for a connection is made, for example by a voice channel or data port which is
routed over the ISDN link (See ROUTING). The ISDN connection will remain up until the last channel
clears its bandwidth request or there is no traffic activity for the configured activity timeout (SYSTEM
menu). It is also possible to specify which end makes the call by setting the other end into Answer mode
(This can be useful for billing purposes).
V100 Versatile Multiplexer Technical Manual Version 2.2
Page 106 of 231