Infiniband optical modules SDR/DDR/QDR/FDR/EDR/HDR/NDR
Dec 08, 2025|
What are EDR and FDR?
There's a type of switch in data centers called an Infiniband switch, which looks like this.
Regardless of their network protocols, for optical modules, EDR and FDR represent the rates of a pair of differential lines.
| Abbreviation | Full Name | Differential Line Rate |
|---|---|---|
| SDR | Single Data Rate | 2.5 Gb/s |
| DDR | Double Data Rate | 5 Gb/s |
| QDR | Quad Data Rate | 10 Gb/s |
| FDR | Fourteen Data Rate | 14 Gb/s |
| EDR | Enhanced Data Rate | 25 Gb/s (actually 25.78125 Gb/s) |
| HDR | High Data Rate | 50 Gb/s (actually 53.125 Gb/s) |
NDR - Next Data Rate, the rate is still unknown, it's the next generation rate.
In our 100G optical modules, there's a category called CXP. C stands for 12 in hexadecimal, X for 10 in Roman numerals, and P stands for hot-swappable.
This type of module can be used in Infiniband's QDR (Quick DR), which is a single-channel 10Gb/s rate.
There are 12 channels, totaling 120 Gb/s.
Then there's the QSFP28, which can be used for EDR, with a single channel speed of 26Gb/s. Q has 4 channels, for a total of 104Gb/s.
If we convert Infinband to an optical module, we can view it like this:
| Rate Type | Single Channel (Gb/s) | 4 Channels (Gb/s) | 12 Channels (Gb/s) |
|---|---|---|---|
| SDR | 2.5 | 10 | 30 |
| DDR | 5 | 20 | 60 |
| QDR | 10 | 40 | 120 |
| FDR | 14 | 56 | 168 |
| EDR | 26* | 104 | 312 |
| HDR | 50* | 200 | 600 |
This type of switch does not account for a large proportion of data centers. Of the 100G optical modules in data centers, about 4% are used for Infiniband, and the majority are Ethernet switches.