Isdn For Resilience - Bay Networks Nautica 200 Reference Manual

NauticaRS Release 4.1 Reference Guide

ISDN for Resilience

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The Nautica Series routers only open the connection when data is
being passed across the ISDN network and close the connection
when no data is being transmitted. When data is transmitted again
after a period of inactivity, the Nautica router automatically opens
the connection. It does this so quickly that, in most situations, you
will not realize that the connection to the remote unit has been
closed.
ISDN means that you no longer need to lease 64 Kb/s or
lower-speed lines to interconnect LANs. The Nautica Series can
take advantage of widespread ISDN availability by providing
several Basic Rate ISDN interfaces or a Primary Rate ISDN
interface (providing up to 30 "B" channels in Europe or 23 "B"
channels in North America). ISDN links can be used to replace
leased lines (as backup if a leased line fails) or in addition to
leased lines (for extra bandwidth as needed).
ISDN is the most cost-effective and responsive means of
providing resilience to line failure. The Nautica Series can be
configured to respond to line failures by connecting to one or
more ISDN channels. Service is usually restored within 3 to 7
seconds, which ensures that users are not interrupted.
The Multilink facility allows data to be shared evenly across all
available links (leased and ISDN), and also allows multiple ISDN
channels to back up a higher-speed leased line. If configurable
load thresholds on any link are exceeded, the Nautica Series
router can be configured to dial up additional bandwidth using
64 Kb/s ISDN channels between router pairs. This greatly
increases the flexibility of network configurations, allowing peak
demand to be covered only when it occurs.
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