How to Check the Optical Transceiver Rate? How to Choose the Correct Rate?

With today’s high traffic growth, data centers are undergoing massive capacity upgrades and expansions, thus the demand for optical transceivers is increasing. In order to meet the needs of different rate networks and application environments, optical transceivers with different transmission rates are available in the market. In view of the fact that some users who have just entered the communications industry are not clear how to view the rate of optical transceivers, this article will briefly explain how to view the rate of optical transceivers and how to choose it.

What are the Optical Transceiver Rates? How to See It?

Optical transceiver rate refers to the number of bits of data transmitted per second (bit), in Mb/s and Gb/s. The rate of optical transceivers on the market today usually ranges from 100Mb/s to 400Gb/s, with common transmission rates of 100Mb/s, 1Gb/s, 10Gb/s, 25Gb/s,40Gb/s, 100Gb/s and 400Gb/s. According to the different transmission rates, optical transceivers can be divided into 100Base optical transceiver (i.e. 100Gb/s), 1G optical transceiver (i.e. Gigabit optical transceiver), 10G optical transceiver (i.e. 10Gb/s), 25G optical transceiver, 40G optical transceiver, 100G optical transceiver and 400G optical transceiver, etc. So in the face of different transmission rates of optical transceivers, and how to identify its rate? View the method as follows.

Method 1

The most intuitive and fastest way to check the speed of an optical transceiver is to check the model name on the label of the optical transceiver. The model name on the label of the optical transceiver generally contains the package form of the optical transceiver, rate, wavelength and transmission distance and other basic parameters, so when we get the optical transceiver, we can first check the model name of the optical transceiver to identify its rate. For example, the model name of NADDOD 10G optical transceiver is SFP-10GSR-85, where 10G means its transmission rate is 10Gbps.



Different manufacturers’ naming rules may differ, but the meaning of the code is basically the same. Users who are not clear about such naming rules can refer to the following table.

Method 2

If the label of the optical transceiver is accidentally lost, we can first determine its package type and rate through the appearance of the optical transceiver initially, and then obtain the optical transceiver rate by reading the DDM information of the optical transceiver.

1. Judgment of Optical Transceiver Package Type

Compared with the optical transceivers developed in the early stage, the optical transceivers nowadays show small size characteristics. Taking NADDOD optical transceiver as an example, we will first teach you how to determine the package type of the optical transceiver based on its size.

(1) SFP series optical transceiver (i.e. 100G/1G/10G/25G) SFP series optical transceiver size is the same, such as the appearance and size of the gigabit transceiver and 10G optical transceiver. sfp series optical transceiver size aspect ratio is 56.5x13.9mm, the pull ring is shorter and fit on the optical transceiver shell body. Earlier 10G XFP/X2/XENPAK optical transceivers are larger than SFP series optical transceivers, with aspect ratios of 77.7x8.5mm, 91.1x36mm, 115.2x36mm respectively, where XFP optical transceivers have the shortest pull ring and X2/XENPAK optical transceivers have no pull ring.

(2) QSFP series optical transceivers (i.e. 40G/100G) QSFP series optical transceivers have the same size, such as 40G QSFP+ optical transceivers and 100G QSFP28 optical transceivers have the same appearance and size. QSFP series optical transceivers have a dimensional aspect ratio of 7818.35mm, and the pull ring is longer and extends outside the shell compared to SFP series optical transceivers. Earlier 100G CFP/CFP2/CFP4 optical transceiver size is larger than QSFP series optical transceiver size, and its aspect ratio is 126.7913.6mm, 107.541.5mm, 9221.5mm respectively, and all of them have no pull ring design.

(3) QSFP-DD series optical transceiver (i.e. 400G) QSFP-DD series optical transceiver size is slightly larger than QSFP optical transceiver size, and its aspect ratio is 92.9*16.42mm, and its pull ring also extends to the outside of the shell, but it is shorter than QSFP series optical transceiver pull ring.



In general, we can identify the package and rate of the optical transceiver by its size and the length of the pull ring. Commonly, SFP series optical transceivers have the smallest size and the shortest pull ring, QSFP-DD optical transceivers have the largest size and longer pull ring than SFP series optical transceivers, and QSFP series optical transceivers have in-between sizes and the longest pull ring.

2. Read the DDM Information

After the initial identification of the package type and rate of the optical transceiver by its appearance, the DDM information of the optical transceiver can be read to obtain its rate. The DDM information of optical transceiver contains the information of optical transceiver type, transmission rate and central wavelength, etc. After users plug the optical transceiver into the switch, they can read the DDM information on the switch to check the rate of the optical transceiver. Take Huawei switch as an example for the specific operation.

Execute the command display transceiver [ interface interface-type interface-number | slot slot-id ] to view the information of the optical transceiver on the device interface. As shown in the figure, 1000_BASE refers to the optical transceiver rate of 1Gbps.



However, not all optical transceivers support querying DDM information, so it is best to confirm whether the optical transceiver has this function before querying.

How to Choose Different Rate of Optical Transceivers?

The package form, transmission distance and application range of different rate optical transceivers are different, so the selection needs to be based on the actual application environment. The following table shows the main application scope of different rate optical transceivers.



In addition to considering the actual application environment, the port rate and package type of the device (e.g., switch) can also be considered in conjunction. The port rate of the device should be the same as the optical transceiver rate, but there are different package types of ports for the same port rate device, so you also need to consider whether the device is compatible with the optical transceiver.

Can a High Speed Optical Transceiver be Used in a Low Rate Port Switch?

The answer is “no”. Because low-rate port switches may not be compatible with high-rate optical transceivers, for example, SFP port switches are not compatible with SFP+ optical transceivers, so generally speaking, high-rate optical transceivers cannot be used in low-rate port switches. So some people may ask, can low-rate optical transceivers be used in high-rate port switches? This depends on whether the high-speed port switch supports adaptive multi-rate, if the high-speed port switch supports adaptive multi-rate, usually can be used, at this time the link rate is low rate. However, from a professional point of view, considering the normal use of the network, it is still recommended that you choose to use an optical transceiver with the same port rate and package as the device.