What Is an Optical Module and Its FAQs
- Fundamentals of an Optical Module
- Appearance and Structure of an Optical Module
- What Key Performance Counters Does an Optical Module Have?
- What Are the Common Types of Optical Modules?
- How Can I Interpret the Name of an Optical Module?
- What Are the Main Causes for and Protection Measures Against Optical Module Failures?
- What Optical Modules Do CloudEngine Series Data Center Switches Support?
- Can Purchased Optical Modules Be Used on CloudEngine Series Data Center Switches?
- What Can I Do If Interconnected Optical Modules on Different CloudEngine Series Data Center Switches Cannot Communicate with Each Other?
Fundamentals of an Optical Module
As an important part of fiber-optic communication, an optical module is a photoelectric converter which converts electrical signals into optical signals and vice versa.
An optical module works at the physical layer of the OSI model and is one of the core components in the fiber communication system. It mainly consists of optoelectronic devices (optical transmitter and optical receiver), functional circuits, and optical bores. Its main function is to convert between electrical and optical signals during optical signal transmission. Figure 1-1 shows how an optical module works.
The transmit optical bore inputs electrical signals at a certain bit rate, which are then processed by the internal driver chip. After the processing, the drive's semiconductor laser diode (LD) or light emitting diode (LED) emits modulated optical signals at the corresponding rate. When the optical signals reach the receive optical bore through an optical fiber, they are converted back into electrical signals by the photodetector diode. The electrical signals are then output at the corresponding bit rate after passing the preamplifier.
Appearance and Structure of an Optical Module
There are various types of optical modules, and their appearances and structures are different. However, the basic structure of an optical module includes some common parts, as shown in Figure 1-2.
Component |
Description |
---|---|
1. Dust plug |
Protects optical fiber connectors, optical fiber adapters, optical bores of optical modules, and ports of other devices from external pollution and damage. |
2. Spring |
Ensures a proper connection between the optical module and the optical port of the device. It exists only on an SFP optical module. |
3. Label |
Displays key parameters and vendor information of an optical module. |
4. Connector |
Connects the optical module to a board for transmitting signals and supplying power to the optical module. |
5. Shell |
Protects internal components. There are two types of shells: 1*9 shell and SFP shell. |
6. Receive optical bore (Rx) |
Receives optical signals. |
7. Transmit optical bore (Tx) |
Transmits optical signals. |
8. Latch |
Used to remove or insert an optical module. For easy identification, the color of the latch varies according to the band. |
What Key Performance Counters Does an Optical Module Have?
We can measure the performance of an optical module based on its key counters. The following describes these key counters for your better understanding.
Transmitter
- Average transmit power
The average transmit power refers to the optical power output by the light source at the transmit end of the optical module under normal working conditions, which can be considered as the luminous intensity. The transmit power is related to the proportion of signal 1s in the transmitted data signals. More signal 1s indicate higher optical power. When the transmitter sends pseudo-random sequence signals, the number of signal 1s is approximately equal to the number of signal 0s. In this case, the power obtained in the test is the average transmit power, in the unit of W, mW, or dBm. W and mW are linear units, and dBm is a logarithmic unit. In communications, dBm is typically used to represent optical power.
- Extinction ratio
The extinction ratio refers to the minimum ratio of the average optical power when the laser transmits all signal 1s (emits light) against the average optical power when the laser transmits all signal 0s (does not emit light) in complete modulation mode. Based on these two parameters, the extinction ratio indicates the capability of identifying signal 0 and signal 1. As such, the extinction ratio can be considered as a measure of the laser operating efficiency. The typical minimum extinction ratio ranges from 8.2 dB to 10 dB. As shown in Figure 1-3, the laser of the optical module's transmitter converts electrical signals into optical signals based on the bit rate of the input electrical signals.
- Center wavelength of an optical signal
The center wavelength is the wavelength measured at the midpoint of a half-amplitude line in the transmit spectrum. Lasers of different types or two lasers of the same type may have different center wavelengths due to factors such as techniques and production processes. Even the same laser may have different center wavelengths under different conditions. Generally, the manufacturers of optical components and optical modules provide the center wavelength parameter, whose value is generally a range. Currently, there are three types of center wavelengths for commonly used optical modules: 850 nm, 1310 nm, and 1550 nm.
Why are they defined in these three bands? This is related to the fiber loss of the optical signal transmission medium. After continuous research and experiments, it is found that the fiber loss is likely to decrease as the wavelength increases. The fiber loss at the 850 nm wavelength is small, but the loss at the 900–1300 nm wavelength increases. The fiber loss starts to decrease at the 1310 nm wavelength and is the lowest at the 1550 nm wavelength, and the loss at the 1650 nm wavelength or higher tends to increase. As such, 850 nm is a short-wavelength window, and 1310 nm and 1550 nm are long-wavelength windows.
Receiver
- Overload optical power
Overload optical power, also known as saturated optical power, refers to the maximum average input optical power that can be received by the receiver of an optical module under a certain bit error rate (BER, which is usually 10-12). The unit is dBm.
Note that the photodetector will have saturated photocurrent when exposed to strong light. When this occurs, the photodetector needs some time to recover. In this case, the receiver sensitivity decreases, and the received signals may be misjudged, causing bit errors. Simply speaking, if the input optical power exceeds the overload optical power, the device may be damaged. Therefore, avoid direct exposure to strong light to prevent the input optical power from exceeding the overload optical power.
- Receiver sensitivity
The receiver sensitivity refers to the minimum average input optical power that can be received by the receiver of an optical module under a certain BER (BER = 10-12). If the transmit optical power refers to the luminous intensity at the transmit end, the receiver sensitivity refers to the luminous intensity that can be detected by the optical module. The unit is dBm.
Generally, a higher rate indicates poorer receiver sensitivity. That is, a higher minimum receive power means higher requirements on the receiver of an optical module.
- Receive power
The receive power refers to the average optical power range that can be received by the receiver of an optical module under a certain BER (BER = 10-12). The unit is dBm. The upper threshold of the receive power is the overload optical power, and the lower threshold is the maximum receiver sensitivity.
In general, when the receive power is lower than the receiver sensitivity, the signals may not be received normally because the optical power is too weak. When the receive power is greater than the overload optical power, signals may fail to be received because of bit errors.
Comprehensive Performance Counters
- Interface rate
The interface rate is the maximum rate of electrical signals that an optical component can transmit without bit errors. The interface rates defined in Ethernet standards include 125 Mbit/s, 1.25 Gbit/s, 10.3125 Gbit/s, and 41.25 Gbit/s.
- Transmission distance
The transmission distance of an optical module is limited by loss and dispersion. The loss of light energy is caused by absorption and dispersion of the medium and the leakage of optical signals when optical signals are transmitted over the optical fiber. This part of energy is dissipated at a certain rate as the transmission distance increases. Dispersion is generated because electromagnetic waves of different wavelengths are transmitted at different speeds in the same medium. As a result, different wavelength components of optical signals arrive at the receive end at different time points due to the accumulation of transmission distances. As a result, pulses are broadened and signal values cannot be identified.
The dispersion-limited distance of the optical module is far greater than the loss-limited distance. Therefore, the dispersion-limited distance can be ignored. The loss-limited distance can be estimated according to the following formula: Loss-limited distance = (Transmit power – Receiver sensitivity)/Optical fiber attenuation. The attenuation of optical fibers is strongly related to their types.
For CloudEngine series switches, you can run the display interface transceiver verbose command to check the general information, manufacturing information, alarms, and diagnostic information about the optical module on a specified interface, as described in Table 1-2.
Item |
Description |
---|---|
Common information |
General information about an optical module. |
Transceiver Type |
Type of an optical module. |
Connector Type |
Connector type. |
Wavelength (nm) |
Optical wavelength. |
Transfer Distance (m) |
Transmission distance. 50 µm or 125 µm indicates the diameter of an optical fiber, and OM2 indicates the level of an optical fiber. |
Digital Diagnostic Monitoring |
Whether diagnostic information of an optical module is monitored. |
Vendor Name |
Vendor name of an optical module. If HUAWEI is displayed, the optical module is a certified optical module for Huawei data center switches. If the value is not HUAWEI, the optical module is not certified by Huawei. |
Vendor Part Number |
Vendor part number of the optical module. |
Ordering Name |
Name of an optical module used for ordering. |
Manufacture information |
Manufacturing information about an optical module. |
Manu. Serial Number |
Manufacturing sequence number of an optical module. |
Manufacturing Date |
Manufacturing date of an optical module. |
Alarm information |
Alarm information about an optical module. |
Diagnostic information |
Diagnostic information about an optical module. If - is displayed, querying diagnostic information about this optical module is not supported or diagnostic information is incorrect. |
Temperature (Celsius) |
Current temperature of an optical module. |
Voltage(V) |
Current voltage of an optical module. |
Bias Current (mA) |
Bias current of an optical module.
NOTE:
If an interface that can be split has an optical module installed, the bias current of each lane in the optical module is displayed. The optical module can work properly only when the bias current of each lane is within the range from Bias Low Threshold (mA) to Bias High Threshold (mA). |
Bias High Threshold (mA) |
Upper bias current threshold of an optical module. |
Bias Low Threshold (mA) |
Lower bias current threshold of an optical module. |
Current RX Power (dBm) |
Current receive power of an optical module. NOTE:
If an interface that can be split has an optical module installed, the receive power of each lane in the optical module is displayed. |
Default RX Power High Threshold (dBm) |
Default upper threshold of the receive power of an optical module. |
Default RX Power Low Threshold (dBm) |
Default lower threshold of the receive power of an optical module. |
Current TX Power (dBm) |
Current transmit power of an optical module. NOTE:
If an interface that can be split has an optical module installed, the transmit power of each lane in the optical module is displayed. |
Default TX Power High Threshold (dBm) |
Default upper threshold of the transmit power of an optical module. |
Default TX Power Low Threshold (dBm) |
Default lower threshold of the transmit power of an optical module. |
What Are the Common Types of Optical Modules?
Classification by Transmission Rate
To meet various transmission rate requirements, optical modules with different rates are provided, including 400GE, 100GE, 40GE, 25GE, 10GE, GE, and FE optical modules.
Classification by Form Factor
A higher transmission rate depends on a more complex structure. Different form factors in different structures are provided for varying transmission rates. Huawei switches support optical modules of the following form factors: Small Form-factor Pluggable (SFP)/Enhanced Small Form-factor Pluggable (eSFP), SFP+, SFP28, Quad Small Form-factor Pluggable Plus (QSFP+), 120 Gb/s eXtended-capability Form Factor Pluggable (CXP), Centum Form-factor Pluggable (CFP), QSFP28, and QSFP-Double Density (QSFP-DD).
Form Factor |
Description |
Appearance |
---|---|---|
SFP/eSFP |
An SFP optical module supports LC fiber connectors. An eSFP optical module is an enhanced SFP optical module that supports monitoring of voltage, temperature, bias current, transmit power, and receive power. Currently, eSFP and SFP optical modules are both called SFP optical modules. |
|
SFP+ |
An SFP+ optical module is an SFP optical module with a higher rate. It is more sensitive to electromagnetic interference (EMI) because of a higher rate. To reduce EMI, SFP+ optical modules have more springs than SFP optical modules and the cages for SFP+ modules on a card are tighter. |
|
SFP28 |
Its form factor size is the same as that of an SFP+ optical module. An SFP28 port can use a 25GE SFP28 optical module or 10GE SFP+ optical module. |
|
QSFP+ |
A QSFP+ optical module supports MPO fiber connectors and is larger than an SFP+ optical module. |
|
CXP |
A CXP optical module is a hot-pluggable high-density parallel optical module, which provides 12 channels of traffic in each of the Tx and Rx directions. It applies only to short-distance multimode links. |
|
CFP |
CFP is a new optical module standard that supports high-speed transmission in data communication and telecommunications fields. The dimensions of a CFP optical module are 13.6 mm x 144.75 mm x 82 mm (H x W x D). |
|
QSFP28 |
Its form factor size is the same as that of QSFP+. Currently, 100GE QSFP28 optical modules and 40GE QSFP28 optical modules are available. |
|
QSFP-DD |
A QSFP-DD optical module is a high-speed pluggable module defined by the QSFP-DD MSA group. |
Classification by Mode
Optical fibers are classified into single-mode and multimode fibers. Therefore, optical modules are also classified into single-mode and multimode modules to support different optical fibers.
Single-mode optical modules have a typical center wavelength of 1310 nm or 1550 nm, and are used with single-mode fibers. Single-mode fibers support a wide band and large transmission capacity, and are used for long-distance transmission.
Multimode optical modules have a typical center wavelength of 850 nm, and are used with multimode fibers. Multimode fibers have lower transmission performance than single-mode fibers because of modal dispersion, but are more cost-effective. They are used for small-capacity, short-distance transmission.
The transmit power of a long-distance optical module is often larger than its overload power. Therefore, when using such optical modules, select optical fibers of an appropriate length to ensure that the actual receive power is smaller than the overload power. If the optical fibers connected to a long-distance optical module are too short, use an optical attenuator to prevent the remote optical module from being burnt. The optical attenuator is the attenuation value of the optical fiber per unit length, in dB/km.
Classification by Center Wavelength
The operating wavelength of an optical module is a range. To facilitate description, the center wavelength is used, in unit of nm.
To support transmission of optical signals in different optical bands, optical modules with different center wavelengths, such as 850 nm, 1310 nm, and 1550 nm, are provided.
Classification by Light Color
The biggest difference between colored optical modules and other types of optical modules lies in the center wavelength.
- Generally, the center wavelength of an optical module can be 850 nm, 1310 nm, or 1550 nm. The center wavelength of an optical module is simple, and the light is called gray light.
- A colored optical module carries light with different center wavelengths. This type of light is called colored light.
Colored optical modules are classified into two types: coarse wavelength division multiplexing (CWDM) and dense wavelength division multiplexing (DWDM). Within the same band, DWDM modules are available in more types and use wavelength resources more efficiently than CWDM modules. DWDM and CWDM modules allow lights with different center wavelengths to be transmitted on one fiber without interfering each other. Therefore, a passive multiplexer can be used to combine the lights into one channel, which is then split into multiple channels by a demultiplexer on the remote end. This reduces the optical fibers required. DWDM and CWDM modules are used for long-distance transmission.
Category (Example)
According to the preceding classification, the following table lists the types of some common optical modules based on different features.
Feature |
SFP-GE-LH40-SM1310 |
SFP-10G-ER-1310 |
QSFP-40G-LR4 |
QSFP-100G-CWDM4 |
QSFP-DD-400G-SR8 |
---|---|---|---|---|---|
Rate |
GE |
10GE |
40GE |
100GE |
400GE |
Form factor |
eSFP |
SFP+ |
QSFP+ |
QSFP28 |
QSFP-DD |
Mode |
Single-mode |
Single-mode |
Single-mode |
Single-mode |
Multi-mode |
Center wavelength (nm) |
1310 |
1310 |
1271, 1291, 1311, 1331 |
1271, 1291, 1311, 1331 |
850 |
Light color |
Gray light |
Gray light |
Gray light |
Colored |
Gray light |
How Can I Interpret the Name of an Optical Module?
Understanding naming conventions of an optical module help you obtain all information contained in the optical module's name. This section uses general naming conventions as an example.
Identifier |
Meaning |
---|---|
A |
Form factor type
|
B |
Rate
|
C |
Transmission distance type
|
D |
Transmission distance, in km |
E |
Module type
|
F |
Center wavelength, in nm |
What Are the Main Causes for and Protection Measures Against Optical Module Failures?
Optical modules must be operated in a standardized manner. Any non-standard operation may result in implicit damage or even permanent failure.
Main Causes for Optical Module Failures
The main causes of optical module failures are optical modules' performance deterioration due to ESD damages and optical links' unavailability incurred by optical bore contamination and damage. The possible causes of optical bore contamination and damage are as follows:
- The optical bore is exposed to the environment and contaminated by dust.
- The end face of the fiber connector is contaminated.
- The end face of the fiber connector with a pigtail is improperly used. For example, the end face is scratched.
- A poor-quality fiber connector is used.
Two main approaches are available to effectively prevent optical module failures: ESD prevention and physical protection.
ESD Prevention
ESD damage deteriorates the performance of optical components or even causes optical component failures. In addition, it is difficult to detect optical components with ESD damage. If an optical component fails due to ESD damage, this failed optical component is hard to locate within a short time.
Operation instructions
- When you transport optical modules, ensure that they are in ESD packages, and do not take them out unless necessary or place them at random.Figure 1-4 Optical modules in an ESD boxFigure 1-5 ESD labelFigure 1-6 Optical modules in an ESD bag
- Before touching an optical module, wear an ESD wrist strap or ESD gloves. Take full ESD measures when installing it.Figure 1-7 ESD glovesFigure 1-8 ESD wrist strap
- Ensure that a device is properly grounded before you test or use it.Figure 1-9 Grounded device
Do not take optical modules out of ESD packages or stack them at random without any ESD prevention measures.
Physical Protection
Lasers and thermoelectric coolers (TECs) inside optical modules can be easily broken or disconnected after collisions. Therefore, physical protections are required during optical module transportation and usage.
Use a dedicated cotton swab to gently rub the stain on an optical bore. A non-dedicated cotton swab may cause damage to the optical bore. If the cotton swab is used with excessive force, the metal in the cotton swab may scratch the ceramic end face.
Tests on installation and removal of an optical module are based on manual operations, so are the push force and pull force. Therefore, do not use tools to install or remove an optical module.
Operation instructions
- Handle optical modules gently and protect them from falling.
- When installing an optical module, push it gently by hand. When removing an optical module, unlatch it first. Never use any metal tools during installation and removal.Figure 1-10 Installing an optical module
- Use a dedicated cotton swab to clean an optical bore and do not insert any metal object into it.Figure 1-11 Cleaning an optical bore with a cotton swab
What Optical Modules Do CloudEngine Series Data Center Switches Support?
You can use the following methods to view the optical modules supported by optical interfaces on CloudEngine series switches:
- Visit the Huawei enterprise technical support website, find the desired product, obtain its Hardware Description, and navigate to "Pluggable Modules for Interfaces" in the document.
- Use the hardware query tool to view the optical modules supported based on the product and version you have selected.
The Hardware Description and the hardware query tool will be continuously updated with the product and version updates.
Can Purchased Optical Modules Be Used on CloudEngine Series Data Center Switches?
CloudEngine series switches must use optical modules that are certified for Huawei data center switches. Optical modules that are not certified for Huawei data center switches cannot ensure transmission reliability and may affect service stability. Huawei is not liable for any problems caused by the use of optical modules that are not certified for Huawei data center switches.
When certifying optical modules for Huawei switches, Huawei comprehensively verifies their functions to ensure their quality. The verification items include optical module installation and removal, transmit power, receive power, signal transmission quality, data reading, error tolerance, compatibility, electromagnetic compatibility (EMC), and environmental parameters.
Table 1-5 lists the common faults and causes when non-Huawei-certified optical modules are used.
Fault |
Cause |
---|---|
An optical module cannot be installed in an optical interface. |
Structures or sizes of some non-Huawei-certified optical modules do not comply with the Multi-Source Agreement (MSA). When such an optical module is installed on an optical interface, the size of this optical module hinders optical module installation on adjacent optical interfaces. |
The data bus on a switch stops responding. |
Some non-Huawei-certified optical modules have defects in data bus designs. Using such an optical module on a switch causes suspension of the connected data bus on the switch. As a result, data on the suspended bus cannot be read. |
Electronic devices of an optical interface are damaged. |
If a non-Huawei-certified optical module with improper edge connector size is used on an optical interface, electronic devices of the optical interface will be damaged by short circuits. |
An alarm is incorrectly reported. |
The temperature monitoring systems of some non-Huawei-certified optical modules do not comply with industry standards and report temperature values higher than the real temperature. When such optical modules are used on a switch, the system will report incorrect temperature alarms. |
Parameter or diagnostic information is incorrectly read or cannot be read. |
Some non-Huawei-certified optical modules have improper settings of the A0 page register, which can cause errors or failures when the system attempts to read parameters or diagnostic information from a data bus. |
An optical module brings electromagnetic interference to nearby devices. |
Some non-Huawei-certified optical modules do not comply with EMC standards and have low anti-interference capability. They also bring electromagnetic interference to nearby devices. |
Services are interrupted when the operating temperature of an optical module is high. |
The operating temperature ranges of non-Huawei-certified optical modules cannot meet service requirements. When they are used under relatively high temperature, the optical power decreases, resulting in service interruption. |
If the label has a Huawei logo, the optical module has been certified for Huawei data center switches.
If the label does not have a Huawei logo, run the display interface transceiver verbose command on the switch to check the vendor name of the optical module. If the value of Vendor Name is HUAWEI, the optical module has been certified for Huawei data center switches. If the value is not HUAWEI, the optical module is not certified for Huawei data center switches. Alternatively, you can send the optical module model information to Huawei technical support engineers for confirmation.
What Can I Do If Interconnected Optical Modules on Different CloudEngine Series Data Center Switches Cannot Communicate with Each Other?
Context
Theoretically, optical modules of the same connector type can be connected. In practice, pay attention to the transmit and receive power ranges and transmission distance. Table 1-6 lists the main factors that affect optical module interconnection.
Factor |
Description |
---|---|
Wavelength |
Do not interconnect optical modules with different wavelengths. Since optical modules with different wavelengths have different transmission loss and dispersion in a fiber, the transmission distances of such optical modules are different even at the same rate. Therefore, you need to select the optical modules with the same wavelength for interconnection. |
Transmission distance |
Optical modules interconnected must have the matching transmission distance. The connector specifications of optical modules vary greatly according to the transmission distance. Long-distance optical modules are expensive. When long-distance and short-distance optical modules are interconnected, optical attenuators must be used. To prevent an optical module from being burnt, the distance supported by the optical module should be longer than the length of the optical fiber connected to it. |
Rate |
The nominal rate of an optical module must be the same as the actual link rate. Low-rate optical modules are prohibited from transmitting high-rate signals. The nominal rate of an optical module must be greater than the interface rate. |
Mode |
Optical fibers and optical modules used together must work in the same mode. That is, single-mode optical fibers are used for single-mode optical modules, and multimode optical fibers are used for multimode optical modules. |
Fault Symptom
Two optical interfaces on different switches are interconnected through optical fibers. The local optical interface is Down, leading to a communication failure between the two corresponding optical modules.
Possible Causes
- The optical modules used on the switches are not certified for Huawei data center switches.
- The optical modules and optical fibers do not match.
- The local optical interface is shut down.
- The transmit power of the local optical module is too low or too high.
- The receive power of the local optical module is too low or too high.
- The two optical modules do not match.
Troubleshooting Procedure
- Check whether the optical module of the Down interface has been certified for Huawei data center switches. CloudEngine series switches must use optical modules certified for Huawei data center switches. Those that are not certified for Huawei data center switches cannot ensure service reliability, and the corresponding optical interfaces may fail to go Up.
- Check whether optical modules and optical fibers match.
- A single-mode optical module (typically with a center wavelength of 1310 nm or 1550 nm) must be used with single-mode optical fibers (typically yellow).
- A multimode optical module (typically with a center wavelength of 850 nm) must be used with multimode optical fibers (typically orange).
- Run the display interface transceiver command to check whether any alarm information has been generated for the optical module.
<HUAWEI> display interface 10ge 1/0/1 transceiver 10GE1/0/1 transceiver information: ------------------------------------------------------------------- Common information: Transceiver Type :10GBASE_SR Connector Type :LC Wavelength (nm) :850 Transfer Distance (m) :30(62.5um/125um OM1) 80(50um/125um OM2) 300(50um/125um OM3) 400(50um/125um OM4) Digital Diagnostic Monitoring :YES Vendor Name :HUAWEI Vendor Part Number :02318169 Ordering Name : ------------------------------------------------------------------- Manufacture information: Manu. Serial Number :AQG269Y Manufacturing Date :2013-10-20 Vendor Name :HUAWEI ------------------------------------------------------------------- Alarm information: -------------------------------------------------------------------
If the LOS alarm is displayed, the local optical interface does not receive signals from the remote interface. Run the display this command in the interface view to check whether the two interfaces have been shut down. If an interface is shut down, run the undo shutdown command on the interface.
- Run the display interface transceiver verbose command to check diagnostic information about the optical module on the local interface. Specifically, check whether the diagnostic information contains alarms about abnormal transmit or receive power.
<HUAWEI> display interface 10ge 1/0/1 transceiver verbose 10GE1/0/1 transceiver information: ------------------------------------------------------------------- Common information: Transceiver Type :10GBASE_SR Connector Type :LC Wavelength (nm) :850 Transfer Distance (m) :30(62.5um/125um OM1) 80(50um/125um OM2) 300(50um/125um OM3) 400(50um/125um OM4) Digital Diagnostic Monitoring :YES Vendor Name :HUAWEI Vendor Part Number :02318169 Ordering Name : ------------------------------------------------------------------- Manufacture information: Manu. Serial Number :AQG269Y Manufacturing Date :2013-10-20 Vendor Name :HUAWEI ------------------------------------------------------------------- Alarm information: ------------------------------------------------------------------- Diagnostic information: Temperature (Celsius) :33.68 Voltage (V) :3.29 Bias Current (mA) :7.97 Bias High Threshold (mA) :13.20 Bias Low Threshold (mA) :4.00 Current RX Power (dBm) :-2.15 Default RX Power High Threshold (dBm) :1.00 Default RX Power Low Threshold (dBm) :-11.90 Current TX Power (dBm) :-2.07 Default TX Power High Threshold (dBm) :1.00 Default TX Power Low Threshold (dBm) :-9.30 -------------------------------------------------------------------
The display interface transceiver verbose command displays the current transmit and receive power values of the optical module, as well as the default maximum and minimum power values.
- If RxPower Low is displayed, the strength of signals received by the local optical module is too low. As a result, the local interface may not go Up or discard packets after it is Up. In this case, check whether the distance between the two switches exceeds the maximum transmission distance of the remote optical module. If the distance is within the transmission distance of the remote optical module, check whether the optical module and optical fiber on the interface are damaged.
- If RxPower High is displayed, the strength of signals received by the local optical module is too high. The possible reason is that the distance between the two switches is short but a long-distance optical module is used on the remote end. In this case, install an optical attenuator on the remote optical module to protect the local optical module.
- If TxPower Low is displayed, the strength of signals sent from the local optical module is too low, or the optical module is faulty. This may cause low receive power on the remote optical module. Then, the remote interface may not go Up or discard packets after it is Up. In this case, contact technical support engineers.
- If TxPower High is displayed, the strength of signals sent from the local optical module is too high. This may cause high receive power on the remote optical module. If the high receive power lasts for a long time, the remote optical module will be burnt. The local optical module may have failed and you are advised to replace it.
To ensure normal communication between two interconnected interfaces that have optical modules installed, check for transmit and receive power alarms. Ensure that the transmit and receive power values of the two optical modules are in the normal ranges. Otherwise, traffic forwarding on the optical interfaces may be abnormal or the optical modules may be damaged.
- If no transmit and receive power alarms are displayed on the two ends but the interface is still Down, collect detailed information and logs about the optical modules, and then replace the optical modules or optical fibers. If the interface can go Up, the original optical modules or optical fibers are faulty. If the interface is still Down, contact technical support engineers.
- Fundamentals of an Optical Module
- Appearance and Structure of an Optical Module
- What Key Performance Counters Does an Optical Module Have?
- What Are the Common Types of Optical Modules?
- How Can I Interpret the Name of an Optical Module?
- What Are the Main Causes for and Protection Measures Against Optical Module Failures?
- What Optical Modules Do CloudEngine Series Data Center Switches Support?
- Can Purchased Optical Modules Be Used on CloudEngine Series Data Center Switches?
- What Can I Do If Interconnected Optical Modules on Different CloudEngine Series Data Center Switches Cannot Communicate with Each Other?