Editing Synchronous optical networking (section)

===Overall functionality===
Network management systems are used to configure and monitor SDH and SONET equipment either locally or remotely.

The systems consist of three essential parts, covered later in more detail:
* Software running on a ''network management system terminal'', e.g. workstation, dumb terminal or laptop housed in an exchange/central office.
* Transport of network management data between the ''network management system terminal'' and the SONET/SDH equipment, e.g. using TL1/Q3 protocols.
* Transport of network management data between SDH/SONET equipment using ''dedicated embedded data communication channels'' (DCCs) within the section and line overhead.

The main functions of network management thereby include:
;Network and network-element provisioning
:In order to allocate bandwidth throughout a network, each network element must be configured. Although this can be done locally, through a craft interface, it is normally done through a network management system (sitting at a higher layer) that, in turn, operates through the SONET/SDH network management network.
;Software upgrade
:Network-element software upgrades are done mostly through the SONET/SDH management network in modern equipment.
;Performance management
:Network elements have a very large set of standards for performance management. The performance-management criteria allow not only monitoring the health of individual network elements, but isolating and identifying most network defects or outages. Higher-layer [[network monitoring]] and management software allows the proper filtering and troubleshooting of network-wide performance management, so that defects and outages can be quickly identified and resolved.

Consider the three parts defined above: