ODVA has released the attached publication - Guidelines-for-Using-Device-Level-Ring-DLR-with-EtherNetIP that details the protocol support for DLR. Be sure to check the ODVA website for any updated versions of this publication.


It’s important to note that the DLR protocol resides at the Data Link layer (2) of the OSI model while the EIP protocol resides@ 5&6 between the transport layer (4) and the Application Layer (7).

 

 

A picture containing text, screenshot, font, brand Description automatically generated    A picture containing text, screenshot, font, businesscard Description automatically generated

 

Since DLR protocol operates at Layer 2 (in the OSI network model), the presence of the ring topology and the operation of the DLR protocol are transparent to higher layer protocols such as TCP/IP and CP 2/2, with the exception of a DLR object that provides a configuration and diagnostic interface.

 

The EIP protocol stack provides support for DLR via interface objects, Hardware and software needed at the Data Link Layer are not within the scope of the EIP protocol. Pyramid Solutions does not distribute logicware for an FPGA which provides the DLR functionality on layer 2.

 

A diagram of a device level ring object Description automatically generated

 

I hope this helps to clarify the differences between the hardware layer protocols such as DRL and the higher layer protocols such as Ethernet IP.