Page 560 - Handbook of Modern Telecommunications

Network Organization and Governance 4-91

• High priority
• Best effort
Enterprises, usually represented by their overseer, are expected to negotiate the right service class for
each of the SAPs, maintained by various service providers.
Each group of the service classes will be characterized by quantifiable service metrics. These metrics
are included into Service-Level Agreements (SLAs).
4.5.3.3.4 Unification of Service Classes and SLAs
Customers need a transparent end-to-end (across multiple service providers) service agreement. Service
providers do have their own ideas and experiences about realistic service classes from their perspective.
To agree with deviation from these ideas is not easy. Many service providers show gaps and weaknesses
in terms of their own services; practically, there are no service portfolios or service catalogs. Even worse,
there are serious gaps in terms of supervising service KPIs for the following reasons:

• The KPIs have not yet been clearly defined
• No unification with metrics
• The tools to supervise metrics are different
• There are no concepts for measurement and supervision
• Reporting is obsolete and still batch oriented
• Status displays (e.g., service views) are not offered
• Accessing measurement data is not supported
Figure 4.5.10 shows a simple structure for one customer with two sites and with two service providers.
There are three service classes for site A, and four for site B, respectively. At the peering point, there is
no seamless transition between the different service classes. The customer is expected to negotiate each
service class with each service provider separately. There is not end-to-end service guarantee. Due to the
different number of service classes, the KPIs cannot be compared to each other.
All these shortcomings must be eliminated, or improved to some degree, at least. Otherwise, no good
results can be accomplished with multiple service providers and multiple sites of the client. If disputes
arise between customers and service providers, the overseer is in charge of arbitration.
The functions of this process step are:
• Publishing service classes
• Publishing service metrics by each provider
• Publishing measurement tools by each provider
• Exchange of existing measurement results and sample reports
• Identification of deltas (deviations) between the desired state and actual state
• Agreements about compromises
• Agreements about the common denominator of all SLAs
• Comparing process steps of service-level management
• Agreements about joint process steps, including the periodicity of reporting
4.5.3.3.5 Review of Existing SLMs
Figure 4.5.11 shows an overview of the most important activities within the service-level management
process, and identifies the following functional blocks:
Preparation of service-level agreements:
• Definition of QoS metrics
• Definition of data sources to compute QoS metrics
• Selection of measurement tools, which may be accepted by both parties
• Evaluation of test results with the measurement tool