COMSPHERE 3600 Series Data Service Units
4-20 March 1999 3610-A2-GB41-60
•Case 5 – Aggregate Switched Backup for TDM
Circuits (Figure 4-15). A point-to-point TDM
circuit can be backed up using the aggregate switch
capability of the DSU. This may be useful if the
DBMs are shared via an external switch.
In this example, the control DSU should be
configured so that AggrSwitch (Aggregate Switch)
is enabled and AgSw Timing (Aggregate Switch
Timing) is set to Aggr. The DBM-S connected to
the aggregate switch port must have Diag Type
(Diagnostic Type) set to None or Disr.
The DSU will take its timing from the Switched 56
DBM when in Dial Backup mode. The DBM-S
should be commanded to dial the remote DBM
using the Dial command, and to activate the data
over the backup line using the switch to Dial
(→Dial) command.
The DSU should then be commanded to switch data
to the backup port using the Backup (Bkup)
command. When this is done, the DSU will
transmit the aggregate data stream (including data,
framing, and diagnostics) through the aggregate
port. To terminate dial backup, send a DrBU
command to the DBM-S and the DSU.
NOTE
During full backup switching (for
aggregate versions only),
diagnostic commands are
routed over the aggregate port
to the remote DSU or DBM.
Only two tests are available to
test the DDS facility: Digital Test
(DT) and Bit Error Rate Test
(BERT).
Figure 4-15. Case 5 – Aggregate Switched Backup for TDM Circuits Configuration