COMSPHERE 3600 Series Data Service Units
D-6 March 1999 3610-A2-GB41-60
Digital Bridge ConfigurationScenarios
The following scenarios describe four possible backup
processes, which are used in typical customer networks:
automatic partial backup, multipoint dial backup with
tributary digital-sharing device, and network management
controlled backup. Read these scenarios; each contains
descriptions that are common to many applications.

Automatic Partial Backup

The assumed configuration for an automatic partial
backup scenario (Figure D-3 shows when dial backup is
not active, while Figure D-4 shows when dial backup is
active) is as follows:
•Network is a 3-drop DDS multipoint network
operating at 9600 bps.
•Customer wants automatic backup controlled by the
tributary DSUs.
•Three central-site DBM-Vs are dedicated to the
control DSU and are connected to its digital bridge.
•The control and tributary DSUs are configured for
mixed diagnostics.
•Tributary DBMs are configured for 9.6 kbps
operation, automatic backup, no fallback, backup
on network fault, Network Time-out period of
1 minute, outgoing call setup with password
security, and automatic restoration of DDS after
5 minutes.
•Central-site DBM-Vs are configured for 9.6 kbps
operation, no fallback, and auto-answer with
password security.
•Digital bridge is configured as a central-site bridge,
has Bridge Rate set to =DSU, has Ports DCE (first
port of the digital bridge) through Prt4 active and
configured for Host contention, taking its timing
from the DDS clock.
•When a failure occurs in the network serving two of
the drops, the two affected DSUs display a network
fault (Alrm LEDs light at the affected DSUs and
begin DDS TimeOut for dial backup). The NMS
and control DSU display a Tributary Time-out
alarm for the two tributaries. Data transmission to
the other drop is not affected.
Figure D-3. Digital Bridge Configuration: Automatic Partial Backup – Dial Backup

Not

Active