Developing rma requirements
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Transcript of Developing rma requirements
DEVELOPING RMA REQUIREMENTS
UNIT – II
Developing RMA Requirements RELIABILITY: (consistency" or "repeatability")
the ability of a system or component to perform its required functions under stated conditions for a specified period of time.
MAINTAINABILITY: performing a successful repair action within a given
time. Used to Maintenance the operations. measures the easy and speed which a system
operational status after a failure occurs. to perform its required functions under stated
conditions for a specified period of time.
AVAILABILITY: in the sense of available useful work. which a system, subsystem or
equipment is in a specified operable and committable state.
MEASURE OF RELIABLILITY: Indicates the frequency of failure
of the network and its components.
MTBF: Mean Time Between Failures
MTBCF: Mean Time Between Mission-Critical Failures
MTBF: Mean Time Between Failure.
A basic measure of reliability. It is the predicted elapsed
time(period of time) between inherent failures of a system during operation.
MTBF is computing the failure rate, which is estimated through testing or analysis in terms of failures per hours of operation.
MTBCF : Mean Time Between Critical Failure. It is sometimes referred to as "mission
reliability" It is a subset of MTBF because it only counts
those failures that result in a mission abort or mission failure.
It is a term used when redundancy exists in a system.
It is often used to differentiate system reliability from series mean time between failure (MTBF).
MEASURE OF MAINTAINABILITY: Statistical measure of the time to
restore the system fully operational status. Once it has experienced a fault.(after repaired)
MTTR: Mean Time To Repair: repairing a failure system consists of detection, isolation (separation) of the failure.
MEASURE OF AVAILABILITY: Relationship between the MTBF, MTBCF,
MTTR. A common measure of availability is
expressed in terms of percent of uptime or downtime.
For example, a request for proposal (RFP) : from a potential customer may state a
required uptime of 99.999% (commonly known as “five nines”).
UP-TIME : Time during the computer is
operational(ON). DOWN-TIME : Time during the computer is NOT
operational(OFF). Availability in terms of uptime and
downtime is measured Per week, per month, or per year based on total amount of time for that period.
Analyzing a network’s availability gives us the
ability to schedule preventive maintenance and replace.Other measures of availability include uptime, downtime, error, and loss rates.
The relationship shown as:
A = (MTBCF) / (MTBCF + MTTR)OR
A = (MTBF) / (MTBF + MTTR)
UPTIME MEASURED OVER DIFFERENT TIME PERIODES
UPTIME: 99% : system to be down quite a bit of
time. 99.9% : 10m applications
stalling(enclose/stand) for several seconds.
99.99% : covers uptime requirements. 9.999% : system being to push
operational limits, network is highly reliable.
DOWNTIME : 99% : considered as low performance.
Measuring uptime
Services are measurable , configurable and verifiable within the system.
Measuring uptime divided into 3 parts: When should it be measured? Where should it be measured? How should it be measured?
Developing DELAY requirements: Interaction Delay(INTD) Human Response Time(HRT) Network Propagation Delay(NPD) End – To – End delay Rountrip Delay Delay variations
Developing CAPACITY requirements
Estimates Data Rates: PDR – peak data rate. MDR – Minimum data rate. SDR – sustained data rate.
Developing supplement : Operational suitability Supportability RMA Workforce