TL1 Protocol: Introduction

Transaction Language1 (TL1) is an ASCII-based management protocol mainly used for managing telecommunication networks. It manages most of the broadband and access networks and is increasingly being used worldwide for newer management applications. Despite its low profile, TL1 today remains the only widely implemented, vendor-independent telecom management protocol.

TL1 serves as a primary interface between the network element and the manager application, and is used to operate, administer, and maintain the network. 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. The data (TL1 messages) are sent and received in the form of byte stream.

The TL1 implementation on the device side and also on the management application allows the user to perform the following functions.

• Alarm and Network monitoring

• Performance monitoring

• Network security and administration

• Retrieving inventory data

Standards Compliant

AdventNet TL1 API is compliant with the Bellcore GR-831-CORE document "Operations Application Messages - Language for Operations Application Message".

Types of Messages

TL1 specifies four types of messages as follows,

• Input Message  is a command from an OS or other source (i.e. manager) to a Network Element (i.e. Agent). The message requests the NE to perform some action.

• Response Message is a detailed reply (or set of replies) to an input command. It contains information indicating whether the command was executed successfully and any data needs to be returned to the OS/user.

• Acknowledgment Message is a short reply from the NE indicating that an input command message is being acted upon or has been immediately rejected. The essential purpose of an acknowledgment is to reassure a user that the NE has received a command that takes a long time to execute.

• Autonomous Message are generated by the NE either on a periodic basis or to report any unusual occurrence of an event in the device.