DEVELOPING SERVICE METRICS

UNIT - TWO

developing service metrics Service metrics: To measure and how to improve

customer interactions and satisfaction. To help analyze trends and overall

performance of Services and Service Management processes.

Performance thresholds and limits and performance characteristics are measured.

developing service metrics Service metrics are either actual

measurable quantities or measured quantities in the network.

Performance characteristics must be configurable, measurable and verifiable within the network.

The types of service metrics you use will depend on your design and the types of equipment.

developing service metrics Service metrics for RMA include: Reliability: in terms of Mean Time Between

Failures (MTBF) and Mean Time Between Mission-Critical Failures (MTBCF)

Maintainability: in terms of Mean Time To Repair (MTTR)

Availability: in terms of MTBF, MTBCF, MTTR.

Optionally Uptime and Downtime (as a percent of total time).

developing service metrics 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.

it can be calculated as the arithmetic mean (average) time between failures of a system.

where all failures that occur over an operating period are counted.

It is sometimes referred to as logistics reliability because it determines the number of spares that you will need to replace items (e.g., parts, assemblies, etc.) that fail.

developing service metrics 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).

developing service metrics Service metrics for capacity include:

Data rates, Peak Data Rate(PDR)Sustained Data Rate(SDR)Minimum Data Rate(MDR)Data sizes:

Burst sizes and durations.

developing service metrics Service metrics for delay include:

End to end or Round-trip delayLatencyDelay variation

Service metrics can be described in terms of variables in network devices:Simple network management protocol(SNMP) Common management information protocol(CMIP)

Examples of variables used as service metrics include:Bytes in/out (per interface)IP Packets in/out (per interface)Dropped Internet control message protocol(ICMP)Service Level agreement (SLA) metrics(per user)

○ Capacity limit.○ Burst tolerance.○ Delay.○ Downtime.

Important terms for definition

FRAME RELAY:Standardized WAN specifies physical and

logical of digital telecommunication channels using packet switch methodology.

Designed for transport across Integrated Service Digital Network(ISDN) Infrastructure.

Important terms for definition

UP-TIME :Time during the computer is operational.

DOWN-TIME :Time during the computer is NOT

operational. CELL LOSS RATIO :

Field of ATM (Asynchronous transfer mode), cell header, indicate the ratio of discarded cells to that are transmitted successfully.

Important terms for definition

CMR:Cells received at the end point that was not

originally transmitted by source end, associated with given traffic load and destination.

PACKET LOSS RATIO:Rate at which packet of data travelling across

a network failed to reach destination.○ ACTIVE – specify link information of packet of

priority○ PASSIVE – know only source and destination.

Important terms for definition

PACKET ERROR RATE:Number of incorrectly received data

packets/ total no of received packets. BIT ERROR RATE:

The number of bit errors is the number of received bits of data stream over a communication channel has been altered due to noise interference, distortion or bit synchronization errors.

Important terms for definition

BURST TOLERANCE:Parameter defined by ATM FORUM (ATM in

Telecommunication network) for ATM traffic management.○ Ex: VBR determines the size of the maximum

burst of contiguous cells that can be transmitted.

MEASUREMENT TOOLS

Various tools to help measure service metrics:Utility ping(TCP/IP)Roughly measures round-trip delays

between selected sources and destinations in the network.

Trace-route:○ path traces.

TCP dump:○ Tool to analyze TCP traffic.

WHERE TO APPLY SERVICE METRICS

It is useful when trying to isolate and track problems in the network.

Especially when there are multiple groups responsible for the network.

Used to separate responsibilities between

An End –to-End provider, A WAN service provider, and other

immediate providers.

THANK YOU