Developing service metrics

1. UNIT - TWO

2. 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.

3. 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.

4. 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).

5. 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.

6. 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).

7. 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.

8. developing service metrics
 Service metrics for delay include:
 End to end or
 Round-trip delay
 Latency
 Delay variation
 Service metrics can be described in
terms of variables in network devices:
 Simple network management protocol(SNMP)
 Common management information protocol(CMIP)

9.  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.

10. 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.

11. 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.

12. 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.

13. 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.

14. 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.

15. 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.

16. 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.

17. THANK YOU