Transaction Language 1

Transaction Language 1 (TL1) is a widely used management protocol in telecommunications. It is a cross-vendor, cross-technology man-machine language, and is widely used to manage optical (SONET) and broadband access infrastructure in North America. TL1 is used in the input and output messages that pass between Operations Systems (OSs) and Network Elements (NEs). Operations domains such as surveillance, memory administration, and access and testing define and use TL1 messages to accomplish specific functions between the OS and the NE. TL1 is defined in Telcordia Technologies (formerly Bellcore) Generic Requirements document GR-831-CORE.

Contents

History

TL1 was developed by Bellcore in 1984 as a standard man-machine language to manage network elements for the Regional Bell Operating Companies (RBOCs). It is based on Z.300 series man machine language standards. TL1 was designed as a standard protocol readable by machines as well as humans to replace the diverse ASCII based protocols used by different Network Element (NE) vendors. It is extensible to incorporate vendor specific commands.

Telcordia OSSs such as NMA (Network Monitoring and Analysis) used TL1 as the element management (EMS) protocol. This drove network element vendors to implement TL1 in their devices.

Language overview

TL1 Messages

The TL1 language consists of a set of messages. There are 4 kinds of messages:

  1. Input message - This is the command sent by the user or the OSS.
  2. Output/Response message - This is reply sent by the NE(Network Element) in response to an input message.
  3. Acknowledgment message - This is an acknowledgment of the receipt of a TL1 input message and is sent if the response message will be delayed by more than 2 seconds.
  4. Autonomous message - These are asynchronous messages (usually events or alarms) sent by the NE.

TL1 message structure

TL1 messages follow a fixed structure, and all commands must conform to it. However, the commands themselves are extensible and new commands can be added by NE vendors.

These are some of the message components:

TL1 input message

Example:

ENT-USER-SECU:MyNE:sridev:101::password;

Structure:

TL1 input message
Command code Staging block Payload block
Verb modifier1 modifier2 TID AID CTAG General block Data block
ENT USER SECU MyNE sridev 101 password

TL1 output message

Example:

MyNE 04-08-14 09:12:04
M 101 COMPLD
"UID=sridev:CID=CRAFT,UAP=1:"
;

Structure:

TL1 output message
Response Header Response Id Response block Terminators
SID Date Time M CTAG Completion code
MyNE 04-08-14 09:12:04 M 101 COMPLD "UID=sridev:CID=CRAFT,UAP=1:" ;

TL1 acknowledgment message

Example:

OK 101
>

Structure:

TL1 acknowledgment message
Acknowledgment code CTAG Terminator
OK 101 >

TL1 autonomous message

Example:

MyNE 04-08-14 09:12:04
A 101 REPT EVT SESSION
"root:NO,"
 ;

Structure:

TL1 autonomous message
Auto Header Auto Id Auto block Terminators
SID Date Time Alarm code ATAG Verb
MyNE 04-08-14 09:12:04 A 101 REPT EVT SESSION

TL1 Surveillance and Maintenance Messages

TL1 also has application messages for NE and transport surveillance functions. The messages and functions cover a wide variety of NE types, user needs, and supplier innovations.

Telcordia GR-833, TL1 Surveillance and Maintenance Messages contains the generic functions and messages that pertain to the following generic types of NEs:

An NE address consists of two types of parameters, routing and access. The maintenance functions can be grouped into the following six categories:

GR-833 provides detailed descriptions of commands and responses in the TL1 format.

External links