ity gaps and SNMP version 2 fixed some security issues regarding privacy of data, authentication, and access control. Information cannot be represented in a detailed and organized manner meet- ing the requirements of next generation network and management due to the simple design. 6.3 Overview of TL1 (Transaction Language 1) The TL1 was developed by Bellcore in 1984 as a man-machine language for network management. The basic intend was to create an open protocol for Fundamentals of EMS, NMS and OSS/BSS managing elements. It consists of a set of ASCII instructions that are human readable. Since TL1 does not require any decoders or debuggers, it has become the preferred CLI (command line interface) for equipment manufacturers. TL1 does not have any message encoding and it does not have an associated infor- mation model. Most of the documentation on TL1 standards was developed by Telcordia. There is a wide range of standard TL1 messages out of which four types com- prise the majority of TL1 communication. They are: Message Explanation Autonomous These are asynchronous messages sent from the messages network element to notify the occurrence of an event. Similar to Trap in SNMP. Input/command These are messages sent from the management messages application to the network element. Output/response These are replies sent by the network element to the messages management application in response to an input/ command message. Acknowledgment These are brief messages from the network element to messages the management application acknowledging the receipt of a TL1 command. Some more specialized standard messaging with TL1 includes provisioning mes- sages and protection switching messages. Advantages of TL1 CLI: Operators and management applications can compose input message and directly interpret responses and events. Delay activation: This feature allows execution of a request at a predeter- mined time. ATAG (autonomous message tag): This tag helps to identify loss of messages in a sequence. Acknowledgment: As per TL1 standa