with the complex environments that are needed to develop and maintain other pro- tocol interfaces, for which development cycles of 9-12 months cause the interfaces to fall behind hardware enhancements. Finally, TL1 is scalable, as it is capable of working with highly scalable management systems such as Bellcore's standard net- work monitoring and analysis system. End-to-end management support for networks of TL1 devices is desirable, including device agent and management applications along with full support for TL1 device management. In the case of AdventNet, this support includes: open APIs and Java bean components for managing TL1 devices a TL1 web-based craft interface on the client side northbound OSS TL1 interface on the server a multi-protocol configuration engine with TL1 support support for TL1 devices in the fault, configuration, assurance, provisioning and security management (FCAPS) and service management applications. As with SNMP and CLI, the TL1 protocol facilitates communication between a managed device, a device with a TL1 agent and a TL1 manager. The TL1 agent on the managed device serves to provide access to data stored on the managed device. The TL1 manager uses this access to monitor and control the managed device. TL1 protocol communicates via TCP with which data are sent and received as TL1 messages in the form of a byte stream. We give an overview of the TL1 Browser from AdventNet to show how TL1 is used by network management OSS. 5.5 TL1 browser The TL1 Browser is a GUI application that can be used to query TL1 devices. It allows the user to view and operate on data that are available through a TL1 agent on a managed device, and manage the device. After starting the browser, a user can connect to any TL1 device and enter any TL1 command in the input message field. To permit a better view of the data available on the TL1 agent, a TL1 file is usually provided with the manager application. This TL1 file contains messages requesting data such as recent activity and faults which can be used to 