Cabletron Systems SmartSwitch SBU128 User Manual page 8

SBU128
User Manual
User
Equipment
SBU128
Figure 1.1 SBU128 sits in the data path
During normal operating conditions, user data passes over the DLC, with
the SBU128 remaining transparent to the system. If a failure occurs on
the DLC, this is detected by the SBU128. After a user defined elapsed
time, the SBU128 dials a remote SmartSWITCH BACKUP unit via the
ISDN line. Upon verification of an acceptable connection the data is
then re-directed over this backup path.
The backup operation is user configured for either automatic or manual
initiation. While the backup data circuit is in use the SBU128 monitors
the failed DLC line and upon detection of its recovery clears the ISDN
call, when data is returned to the DLC line (main leased circuit).
Note that the SmartSWITCH BACKUP product range was previously
known as the CyberBACKUP range, denoted by 'CBU' instead of 'SBU'.
1–2
ISDN
(Backup Circuit)
Digital Leased Circuit
N N
T T
U U
(Main Circuit)
User
Equipment
SBU128
80-10200000-01