Page 461 - Handbook of Modern Telecommunications

3-252 CRC Handbook of Modern Telecommunications, Second Edition

3.10.4.5.2 Service Subscription Lifecycle Support
Assurance support for the service subscription lifecycle provides us with what is often called service
monitoring or service management. The focus here is to monitor the end-to-end services being delivered
to customers, whether individually per customer or aggregated across customer groups.
While fault and performance management need to have components that are domain-specific, we also
need to have a consolidated view across all domains. This is important since a fault in one domain can
cause faults in other domains. Through facilities such as cross-domain root cause analysis, consolidated
operations provides the ability to understand the underlying cause of a number of related failures. Through
service impact analysis, it provides a mechanism to identify which services are affected by a fault.
Service quality management monitors whether the services delivered match the customer expecta-
tions. This goes beyond Service-Level Agreement (SLA) monitoring. Not all customers will have a for-
mal SLA. However, every customer has expectations about the service quality. These will be set either by
a formal SLA, by the service provider’s marketing department, or by the competition. In any case, not
meeting the service expectations results in dissatisfied customers and churn.
This does not imply that every customer’s individual service level delivered for every service session
must be monitored. While this may be practical for some services, it may be prohibitively expensive and
thus not cost effective for other types of services. In many cases, especially with mass-market consumer
services, the requirement is to have an aggregate view across the customer base, with the ability to focus
on particular customers when required.
Finally, the service subscription lifecycle also needs to deal with incidents and problems. While the tools
for resource and service-level incident/problem management may differ, they need to work together.

3.10.4.5.3 Service Offer Lifecycle Support
The assurance aspects of the service offer lifecycle provide information that can help ensure that the
business expectations are being met. This information is generally not directed toward the operations
department but rather toward the line of business managers responsible for the various products.
For example, service offer monitoring will monitor if the service expectations being negotiated in
SLAs or set by the marketing department are reasonable. If the expectations are too high, then either the
services or infrastructure needs to be improved to meet the expectations or the expectations need to be
lowered. If the expectations are too low, then the service provider may be able to market more aggressive
service expectations (thus gaining competitive advantage) or reduce costs by scaling back the require-
ments on the infrastructure.
3.10.4.6 Usage
The TMF talks about FAB, or fulfillment, assurance, and billing. While that makes for a nice acronym,
the term billing is too limiting for what is really involved. While billing for the services delivered is criti-
cal, much more needs to be provided than just billing. This is captured by using the broader term usage.
Figure 3.10.6 provides an overview of usage functions.
The usage area is traditionally handled by the BSS and not the OSS. However, since there is a move
toward convergence of OSS and BSS, we provide an overview of the usage functionality here.
Usage mediation collects usage data from the infrastructure and correlates this into usage data for
each service session. While the primary use of this information is billing for usage, the usage records
often contain additional valuable information, such as session quality, which can be used by the assur-
ance processes.
While usage mediation is sufficient for postpaid billing, prepaid and pay now billing schemes require
charge control mechanisms that can authorize session initiation based on account balance, terminating
the session if necessary when a balance is exhausted.
For postpaid billing, charging and billing translates the session usage information into bills for indi-
vidual customers. This includes rating the usage or each session and aggregating it into a periodic bill.