What is DDM and DOM used in Optical SFP/SFP+ Transceivers?

What is DDM (Digital Diagnostic Monitoring)?

DDM or Digital Diagnostic Monitoring is a management technology which allows operators to monitor several parameters of a fibre optic transceiver, such as optical input/output levels, temperature, laser bias current and supply voltage. All of these parameters can be monitored in real-time.

Examples of optical modules supporting DDM are the Small Form Factor Pluggable modules such as SFP and SFP+ for 1Gbps to 10Gbps and up to 25Gbps capacity

SFP / SFP+ Optical Module with DDM / DOM Monitoring features
SFP module with DDM / DOM Feature

What does the DDM do exactly?

DDM is capable of providing component monitoring on transceiver applications in great detail. The system that is used is an extension of the interface defined in GBIC specification (GBIC being a type of transceiver).

The interface itself is capable of generating alarms and warning flags which alert the host system when operating parameters fall outside of a set of ‘normal operating’ rules. This allows the end user to isolate faults and predict failure.

What is DOM?

DOM or Digital Optical Monitoring is used to monitor certain parameters of an optical transceiver in real-time. This helps operators to identify the location of a fiber link failure which in turn helps to simplify the maintenance process and improve overall system reliability.

DOM gives you the ability to monitor the transmit and receive power of the optical transceiver module, its temperature and supply voltage. Each system can be configured to monitor transceivers that are in operation either globally or by specific port.

With DOM console message and syslog messages are sent if operation falls below or rise above the specific transceivers manufacturer thresholds.

Most modern transceivers support DOM functions.

Schematic diagram of Optical SFP/SFP+ module with DDM / DOM features
Schematic diagram of Optical SFP/SFP+ module with DDM / DOM features available on the (0) (1) and (2) pins

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