Low Level Reader Protocol

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The Low Level Reader Protocol ( LLRP ) is a protocol for communication with RFID readers via TCP . The LLRP was ratified by EPCGlobal in order to standardize the interface between RFID applications and RFID readers; it is therefore in the application layer of the OSI model . The current version is LLRP Standard v. 1.0.1.

The aim of the LLRP is to make all standard features of communication between an RFID reader and an RFID tag in accordance with the EPCGlobal tag protocol EPC Class 1 Gen 2 usable in communication between RFID readers and RFID applications. Furthermore, RFID readers should be able to be controlled (e.g. activated and deactivated) and configured (e.g. changing the number and emitted power of the connected antennas) using this protocol. The LLRP should be able to be used regardless of the applicable regulations (e.g. which power may be emitted in which frequency ranges).

The protocol is modular, flexible and expandable - on the one hand to allow future developments to flow into the protocol with little effort, on the other hand to enable manufacturers of RFID readers to expand the protocol with manufacturer-specific commands.

functionality

The communication units between the client and the RFID reader (which has the role of the server in the LLRP ) are called messages . Messages can be sent from the client to the reader as well as from the reader to the client. After the connection has been established, communication goes through the following phases:

  1. The client asks the reader which features are supported by the reader
  2. The client configures the reader (e.g. sets the frequency to be used)
  3. (optional) The client changes the reader parameters for communication with the tags (e.g. access password for writing to the tags)
  4. The reader searches for tags in its reading field and carries out the operations specified by the client
  5. The reader ends the interaction with the tags
  6. The reader reports the results of the operations performed to the client

The first three steps are not absolutely necessary for further operations. For example, the client can have the reader carry out several write operations in succession, but phases 1 and 2 only have to be run through once.

Individual evidence

  1. ↑ LLRP Standard v. 1.0.1 (PDF; 2.9 MB)

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