Network Operational Management

Ch 6.1 IntroductionCh 6.2 Service Problem Resolution ProcessCh 6.3 Service Quality Management Process 6.3.1 Manage life cycle of service/product portfolio 6.3.2 Monitor overall delivered Quality of a service

Nik Salleh

6.1 Introduction

• Service assurance processes are changing towards proactive support through automation, not triggered by the customer.– Improves service quality– Improves customer perception of service– Lowers cost

• To provide interactive support– Customer can see & act on service performance

6.2 Service problem resolution process

• Isolate the cause of service-affecting and non-service affecting failures, and resolve them.

• By immediate reconfiguration or other corrective actions, or long term modifications to the service design or network components.

• Initiate quality improvement efforts.• Tasks:

– isolate and resolve service problems– identify chronic failure– provide performance data– Recommend service redesign, if appropriate– Initiate escalation procedures– Analyze service quality– Generate reports about services

…Service problem resolution process6.2.1 Isolate and resolve service problems

• reactive fault management (for most cases)– driven by customers via the Problem handling

process.– fault correlation takes place, then information

automatically presented on the affected services and customers.

– Service resolution process identifies the problem, then notifies Problem handling.

…Service problem resolution process…6.2.1 Isolate and resolve service problems

Reactive fault management - steps• Detect & locate the problem (indicates that something is wrong):

by messages, events, and alarms from network components. Alarm filtering & user input help detect abnormal operations. Management applications determine location of faults.

• Determine the cause of the problem (indicates what is wrong): determine cause of problem from information generated by element managers or correlation results.

• Diagnose the root cause of problem (indicates why the problem happens): determine root cause of the problem by detailed tests, measurements, further correlation messages, alarms, events.

• Correcting the problem (indicates that the problem has been solved): by hardware & software techniques, managed objects are repaired or replaced, and operations returned to normal.

…Service problem resolution process…6.2.1 Isolate and resolve service problems

• Proactive fault management– same as Reactive fault management except in first

step (Detecting & locating the problem).– network monitoring detects abnormal performance,

then alarms the maintenance & restoration process to initiate correction.

– fault correlation: automatically diagnose network problems and determine root cause.

– Problem handling process is notified about status.– depending on severity of detected problem,

customers are notified.– Partitioning when presenting network status – allows

views to be presented for different groups

…Service problem resolution process…6.2.1 Isolate and resolve service problems

• Preventive fault management– goes one step further by allowing real time

modeling of what-if scenarios.– results from modeling can be used to

recommend configuration changes.

…Service problem resolution process6.2.2 Identify chronic failures

• Statistical evaluation of chronic service failures– collect history data on service outages, then analyze.

• Steps:– sort service outages by severity, by duration of

service impact, by outage frequency.– service providers set the priorities to tackle the

outages. (highest priority to cases with severe service impact and high frequencies).

– Network maintenance and restoration process analyze high priority items for root-cause analysis.

– from the analysis results, identify the critical network elements and their suppliers.

– copy this information for order processing.

…Service problem resolution process6.2.3 Provide performance data

• Performance data are evaluated for various layers of the Telecommunication Management Network (TMN) architecture.

• in particularly, the service, network, and element management layers.

• In physical networks– Alerts based on support infrastructure, optical sheath degradation,

optical levels, modal dispersion, BER.

• On IP & switching networks– Alerts based on utilization, latency, jitter, congestion

• correlates service performance data with network facilities and equipment for the network and network elements layers.

…Service problem resolution process6.2.4 Recommend service redesign, if appropriate

• Takes internal inputs from the previous processes and evaluates whether services must be redesigned for performance reasons.

• Uses what-if scenario service models to evaluate alternatives for various services.

• recommends to redesign service based on modeling results.

…Service problem resolution process6.2.5 Initiate escalation procedure

• Escalation procedures are prepared prior to launching services.

• Involves multiple dimensions:– service metrics that are measured and continuously evaluated

for unusual conditions.– determination of severity levels for service-related problems.– clarification of management hierarchy to determine notification

route.– setting time limits for the restoration within each severity class

• Severity levels, examples– Important, Very important, Critical, Very critical

• Potential management hierarchy, examples– Shift supervisor, Manager of duty, Site manager

…Service problem resolution process6.2.6 Analyze service quality

• Service providers analyze the trends of service quality based on data collected for service metrics.

• set thresholds for quality alarms, higher than agreed in SLAs.

…Service problem resolution process6.2.7 Generate reports about service

• Performance reporting– automatic generation of business reports showing

network, service, and process performance.– allows online access to performance by customers.– this opportunity enables customers to manage their

purchased services, providing information on network availability, service availability, and maintenance SLAs and performance.

6.3 Service quality management process

• This process supports monitoring service or product quality on a service class basis in order to determine if– service levels are being met consistently– there are any general problems with the

service or product– the sale and use of the service is following the

forecasts

…6.3 Service quality management process

• In IP-based services, the term Quality is relatively new.– the idea is to offer best effort quality depending on the

capacity constraints of networking infrastructures.

• Two alternatives with IP-based services– IntServ (integrated services)

• supports Reservation Protocol (RSVP), thus guarantees bandwidth for application network ingress and egress points.

– DiffServ (differentiated servcies)• analyzes ToS header (type of service) of IPv4 and assigns

priorities based on ToS entries.

…6.3 Service quality management process6.3.1 Manage life cycle of service / product portfolios

• Continuously evaluates the viability of products and services.

• multiple data sources must be interpreted and correlated to each other.

• Continuously evaluate products & services– recommends improvements (e.g. to increase

capacity)– if products or services are no longer feasible,

conveys this message to sales process.

…6.3 Service quality management process 6.3.2 Monitor overall delivered Quality of a Service class

• Collects input for service quality.• Evaluates a number of QoS metrics for

voice, data, and video services.• Service differentiation dictates various

thresholds for service metrics.• Monitoring results are sent to the customer

QoS management process.