Cisco Cisco Packet Data Gateway (PDG) Documentation Roadmaps
Redundancy and Availability Features
▀ Mean Time Between Failure and System Availability
▄ Cisco ASR 5000 Series Product Overview
OL-22937-01
System Availability
System-level Mean Time To Failure (MTTF), is the average interval of time that a component will operate before
failing. Reliability information is based on the number of overall anticipated failures of the individual components, in
conjunction with any redundancy schemes employed to minimize the impact of such failures.
failing. Reliability information is based on the number of overall anticipated failures of the individual components, in
conjunction with any redundancy schemes employed to minimize the impact of such failures.
The following table provides service availability calculations (based on reliability modeling) for the ST16 and ASR
5000 platformsASR 5000 platform.
5000 platformsASR 5000 platform.
Table 39.
Platform Service Availability Calculations
Platform
Operational Uptime
Yearly Downtime
MTTF
(%)
(minutes)
Hours
Years
ST16
99.999173
4.35
336,180
38.37
ASR 5000
99.999978
0.12
14,077,473
1605.91
One suggestion to help improve overall system availability is to institute an on-site spares program, wherein key
components are housed locally with the deployed equipment. The following section defines a recommended spares
program and quantities for the system.
components are housed locally with the deployed equipment. The following section defines a recommended spares
program and quantities for the system.
Mean Time To Repair (MTTR) is the amount of time needed to repair a component, recover the system, or otherwise
restore service after a failure. System availability calculations are based on the industry standard of four hours.
restore service after a failure. System availability calculations are based on the industry standard of four hours.