363-206-295
Technical Specifications
10-40
Issue 1
December 1997
DDM-2000 OC-12 System Reliability Predictions
1
0
Example:
The unavailability of one two-way DS3 channel within one DDM-2000 OC-12 system configured to
multiplex DS3 to OC-12, located in an uncontrolled environment, is 0.499 minutes per year (that is,
fraction of time per year when the DS3 channel is unavailable). The mean time between outage of
the DS3 channel is 483 years (that is, average length of time until a DS3 outage occurs).
Notes
:
1. Hardware failure rates are calculated per the RPP method, TR-NWT-000332, Issue 4,
"Reliability Prediction Procedure."
2. The environmental factor for the CO = 1.0 and for the RT = 1.5, per TR-NWT-000332, Issue 4,
"Reliability Prediction Procedure."
3. Bellcore criteria (Outage Requirements and Objectives) is based on TA-TSY-000418, Issue 3,
"Generic Reliability Assurance Requirements for Fiber Optic Transport Systems." Outage is in
minutes per year.
4. Mean time to repair is assumed to be 2 hours for the CO and 4 hours for RT environment.
Table 10-21. DDM-2000 OC-12 System Reliability Prediction (Note 1)
Application
Environment
(Note 2)
Bellcore Criteria (Note 3)
Prediction
(Outage,
min/yr)
MTBF
Years
(Note 4)
Requirement
Objective
DS3 to OC-12
DS3 to OC-12
CO
RT
1.75
5.25
0.25
0.75
0.163
0.499
736
483
EC-1 to OC-12
EC-1 to OC-12
CO
RT
1.75
5.25
0.25
0.75
0.253
0.764
473
314
OC3 to OC-12
OC3 to OC-12
CO
RT
1.75
5.25
0.25
0.75
0.0015
0.0131
61,900
13,760
OS Interface TL1/X.25
CO
14
7.1
16.9
