Page 315 - Optical Communications Essentials

Source: Optical Communications Essentials

Chapter
18

Network Management

A telecommunications service provider typically will offer a legal contract
known as a service-level agreement (SLA) to its business customers. The terms
of the SLA state that the service provider guarantees a measurable quality of
service (QoS) to the customer. For example, an SLA may guarantee to a cus-
tomer that the service will be available 99.999 percent of the time with a desig-
nated bit error rate (BER) within a monthly or annual time period. If the SLA
guarantees are not met, the customer usually will receive a rebate. Thus there
is a financial incentive for the service provider to manage and monitor the key
performance parameters of the network very closely. The performance and
operations management of a network requires the ability to configure and moni-
tor network devices quickly and easily so that connections and services are
always available. Early detection of changes in network status is critical in
avoiding potential problems. This requires the use of sophisticated instruments
and software-based diagnostic tools.
Thus, once the hardware and software elements of an optical network have
been installed properly and integrated successfully, they need to be managed to
ensure that the required level of network performance is met. In addition, the
network devices must be monitored to verify that they are configured properly
and to ensure that corporate policies regarding network use and security proced-
ures are being followed. This is carried out through network management, which
is a service that uses a variety of hardware and software tools, applications, and
devices to assist human network managers in monitoring and maintaining net-
works. The International Organization for Standardization (ISO) has defined five
primary conceptual areas of management for networks. These functional areas
are performance, configuration, accounting, fault, and security management.
In an actual system, different groups of network operations personnel normally
take separate responsibilities for issues such as administration aspects, per-
formance monitoring, network integrity, access control, and security. There is
no special method of allocating the various management functions to particular

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