As the application of optical modules in optical communication becomes more and more extensive, the speed, packaging, power consumption and functions are all developing in the direction of high speed, small size, low power consumption and multi-function. When you search the SFP, you always see that 'DDM support'. So what is DDM?What does DDM mean？Now let's talk about the Digital Diagnostic Monitoring (DDM) function.
![What is DDM?]( "What is DDM?")
Definition of DDM
DDM (Digital Diagnostic Monitoring), formulated by the industry organization SFF Committee, works in accordance with the standard parameters defined by the SFF-8472 multi-source protocol, and regulates the standard values or ranges that the software and hardware of optical modules and network equipment need to follow. The interoperability of the products offered between network equipment suppliers and optical module suppliers is ensured. DDM is a real-time parameter monitoring technology for optical modules, including operating voltage, operating temperature, received optical power, transmitted optical power and laser bias current.
Functions of DDM
In addition to monitoring parameters, DDM also has other functions such as alarming, fault prediction and fault location.
1. Alarming: When the environmental parameters of the optical modules exceed the specified standard range, an alarm will be sent to the system, indicating that the module is in a bad state, the transmitter will stop sending data, and the receiver will also refuse to receive data.
2. Fault prediction: To predict the degradation of the laser by monitoring the bias current of the laser, so as to ensure that the service is switched to the standby link or the optical modules that may fail before the fault occurs, so it plays a big role in predicting the life of the optical modules .
3. Fault location: Through comprehensive analysis of alarm signs or alarm conditions, monitoring parameter information and optical module pins, etc., the location of link faults can be quickly located, thereby reducing the repair time of system fault.
How to View DDM Information
There are two main ways to view the DDM information of an optical module: SNMP and commands.
1. SNMP, the Simple Network Management Protocol, is a standard protocol specially used for IP network management of network nodes. The optical module DDM information like the received optical power and transmitted optical power can be read through SNMP.
2. Due to different brands of equipment suppliers, the MIB (Management Information Base) and OID (Object Identifiers) of SNMP are different, some devices can obtain DDM information directly through simple commands. For example, enter the Display command on a Huawei switch.
After reading the above content, you should have a preliminary understanding of DDM. Basically the optical modules provided by BEIHAI all have DDM functions, and are widely compatible with major brands of switches. You can buy with confidence! Of course, you can also contact our customer service for confirmation before purchasing.