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  • WDM Optical Networking Solutions

    COMPUFOX offers a number of  WDM Optical Networking solutions which allow transport associated with a mix of services up to 100 GbE over dark fiber and WDM networks providing for the whole set of probably the most demanding CWDM and DWDM network infrastructure needs. Because the physical fiber optic cabling is expensive to implement for every single service separately, its capacity expansion using a WDM is a necessity.

    WDM Architectures

    WDM architecture


    WDM (Wavelength Division Multiplexing) is a concept that describes combination of several streams of data/storage/video or voice on the same physical fiber optic cable by utilizing several wavelengths (or frequencies) of light with each frequency carrying a different sort of data. There's two types of WDM architectures: CWDM (Coarse Wavelength Division Multiplexing) and DWDM (Dense Wavelength Division Multiplexing). CWDM systems typically provide 18 wavelengths, separated by 20 nm, from 1470nm to 1610nm according to ITU-T standard G.694.2. However, for different applications, there are different ITU-T standard to define the specific wave range and channels. Compared to CWDM, DWDM is defined in terms of frequencies. Some DWDM network systems provide up to 96 wavelengths, typically without any more than 0.4 nm spacing, roughly over the C-band range of wavelengths.

    CWDM Technology

    CWDM is proved to be the initial access point for many organizations due to its lower cost. Each CWDM wavelength typically supports as much as 2.5 Gbps and could be expanded to 10 Gbps support. This transfer rates are sufficient to aid GbE, Fast Ethernet or 1/2/4/8/10G Fibre Channel, along with other protocols. The CWDM is limited to 16 wavelengths and is typically deployed at networks as much as 80 km since optical amplifiers can't be used due to the large spacing between channels.

    DWDM Technology

    DWDM is a technology allowing high throughput capacity over longer distances commonly ranging between 44-88 channels/wavelengths and transferring data rates up to 100 Gbps per wavelength. Each wavelength can transparently have a wide range of services. The channel spacing from the DWDM solutions is defined by the ITU standards and can range from 50 GHz and 100 GHz (the most widely used today) to 200 GHz. DWDM systems can provide up to 96 wavelengths (at 50 GHz) of mixed service types, and can transport to distances up to 3000 km by deploying optical amplifiers (e.g., DWDM EDFA) and dispersion compensators thus enhancing the fiber capacity with a factor of x100. Due to its more precise and stabilized lasers, the DWDM technology tends to be more expensive in the sub-10G rates, but is really a more appropriate solution and it is dominating for 10G service rates and above providing large capacity data transport and connectivity over long distances at affordable costs.

    Note: COMPUFOX WDM optical networking goods are designed to support both CWDM and DWDM technology by utilizing standards based pluggable  CWDM/DWDM Transceivers such as SFP, XFP and SFP. The technology used is carefully calculated per project and according to customer requirements of distance, capacity, attenuation and future needs.


    The main benefit of CWDM is the price of the optics that is typically 1 / 3 of the price of the equivalent DWDM optics. This difference in economic scale, the limited budget that lots of customers face, and typical initial requirements to not exceed 8 wavelengths, means that CWDM is a popular entry point for a lot of customers. With COMPUFOX WDM equipment, a customer can start with 8 CWDM wavelengths however grow by introducing DWDM wavelengths in to the mix, utilizing the existing fiber and maximizing roi. By utilizing CWDM and DWDM network systems or the mixture of thereof, carriers and enterprises are able to transport services as much as 100 Gbps of data.

    Typically CWDM solutions provide 8 wavelengths capability enabling the transport of 8 client interfaces over the same fiber. However, the relatively large separation between your CWDM wavelengths allows growth of the CWDM network with an additional 44 wavelengths with 100 GHz spacing utilizing DWDM technology, thus expanding the present infrastructure capability and making use of the same equipment included in the integrated solution.


    Additionally, the normal CWDM spectrum supports data transport rates as high as 4.25 Gbps, while DWDM is utilized more for large capacity data transport needs as high as 100 Gbps. By mapping DWDM channels inside the CWDM wavelength spectrum as demonstrated below, higher data transport capacity on the same fiber optic cable is possible without any requirement for changing the existing fiber infrastructure between the network sites. As demonstrated through the figure beside, CWDM occupies the following ITU channels: 1470 nm, 1490 nm, 1510 nm, 1530 nm, 1550 nm, 1570 nm, 1590 nm, and 1610 nm, each separated from the other by 20 nm. COMPUFOX can insert into the of the 4 CWDM wavelengths (1530 nm,1550 nm,1570 nm and 1590 nm), a set of additional 8 wavelength of DWDM separated from one another by only 0.1 nm. By doing so up to 4 times, the CWDM network capability can easily expand by up to 28 additional wavelengths.

    The other figure below further demonstrates in detail the expansion capabilities via the DWDM spectrum. As seen below, just one outgoing and incoming wavelength of the existing CWDM infrastructure can be used for 8 DWDM channels multiplexing in to the original wavelength. Since this DWDM over CWDM network solution is integrating the DWDM transponders, DWDM MUX/DeMUX and EDFA (optical amplifier if needed), the entire solution is delivered simply by adding a really compact 1U unit. This expansion is achieved with no service interruption to the remaining network services, or to the data, and with no need to change or replace any of the working CWDM infrastructures.


    Advantages of COMPUFOX WDM Optical Networking Solutions

    COMPUFOX CWDM and DWDM network equipment provides the following advantages:
    Low-cost initial setup with targeted future growth path.
    Easy conversion and upgrade capabilities up to 44 wavelengths
    Easy upgrade to support 10G, 40G and 100G services
    Seamless, non traffic effective network upgrades
    Reliable, secure, and standards based architecture
    Easy to install and maintain
    Full performance monitoring

    With COMPUFOX compact CWDM solutions, you could get all of the above benefits and much more (such as remote monitoring and setup, integrated amplifiers, protection capabilities, and integration with 3rd party networking devices, etc.) inside a cost effective 1U unit, enabling you to expand as you grow, and utilize your financial as well as physical resources towards the maximum.

    To purchase your CWDM and DWDM transceivers, please click on the links below:


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  • How to Install or Remove SFP Transceiver Modules on Cisco Device

    The SFP (small form Factor pluggables) transceiver modules are hot-pluggable I/O devices that plug into module sockets. The transceiver connects the electrical circuitry of the module with the optical or copper network. SFP transceiver modules are the key components in today's transmission network. Thus, it is necessary to master the skill of installing or removing a transceiver modules to avoid unnecessary loss. This tutorial are going to guide you how to install or remove SFP transceiver module in a right way.


    Things you should Know Before Installing or Removing SFP

    Before removing or installing a Transceiver Module you must disconnect all cables, because of leaving these attached will damage the cables, connectors, and the optical interfaces. At the same time please be aware that do not often remove and install an SFP transceiver and it can shorten its useful life. For this reason transceivers should not be removed or inserted more often than is required. Furthermore, transceiver modules are sensitive to static, so always ensure that you use an ESD wrist strap or comparable grounding device during both installation and removal.


    Required Tools

    You will need these tools to install the SFP transceiver module:
    Wrist strap or other personal grounding device to prevent ESD occurrences.Antistatic mat or antistatic foam to set the transceiver on.Fiber-optic end-face cleaning tools and inspection equipment


    Installing SFP Transceiver Modules

    SFP transceiver modules can have three types of latching devices to secure an SFP transceiver in a port socket:
    SFP transceiver with a Mylar tab latch.SFP transceiver with an actuator button latch.SFP transceiver that has a bale-clasp latch.
    Types of SFP Latching

    Determine which type of latch your SFP transceiver uses before following the installation and removal procedures.

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  • Optics and Cables Selection for Storage Area Network (SAN)

    Optics and cables are the most important infrastructures of network connectivity. In a storage area network (SAN), switches are used between servers and storage devices. This means that you should make connection with optics and cables between the server and switch, storage and switch as well as the switch and switch. Of course, according to different application environments, you should choose different optics and cables in order to get the best performance. Furthermore, you may need to consider the future expansion of your network. Thus, an economical and effective solution of optics and cables are very necessary.

    Key Factors Influencing Your Decision

    Firstly, there are some key factors which will influence your decision. Thus, you must make sure that what your network really requires. As we mentioned above, an SAN has server, storage device and switches. So, what should we consider in every section of the network?

    1. Server
    Bandwidth: Depending on the application load requirements, customers typically decide whether they want 1GbE, 10GbE, or 40GbE. In some cases, the decision may also be dictated by the type of traffic, e.g. DCB (Data center bridging) requires 10GbE or higher.Cost: Servers claim the highest share of devices deployed in any data center. Choosing a lower cost connectivity option results in a much lower initial deployment cost.Power: In any high density server deployment, a connectivity option which consumes lower power results in much lower OpEx.Distance: Servers are typically connected to a switch over a very short distance, i.e. typically within the same rack or, in some cases, within the same row.Cabling Flexibility: Some customer prefer to make their own copper cables due to variable distance requirement. This requirement limits the choice of connectivity to copper cables only.


    2. Storage
    Reliability: Typical storage traffic is very sensitive to loss. Even a minor loss of traffic may result in major impact on application performance.Qualification: Storage vendor qualification or recommendation plays an important role in this decision due to reasons such as customer support, peace of mind, etc.Latency: Any time spent in transition is time taken away from data processing. Reducing transition time results in much faster application performance. The result may have a direct impact on customers' bottom line, e.g. faster processing of online orders.


    3. Switch
    Bandwidth: On server facing ports, servers typically dictate the per port bandwidth requirement. However, per port bandwidth requirement for the network facing (switch-to-switch) ports denpends on multiple factors including amount of traffic generated by the servers, oversubscription ratios, fiber limitations, ect.Distance: An inter-switch or switch to router connection could range from a few inches to tens of kilometers. Generally, the price of optics increases as the distance increases.Latency: The network topology and application traffic profile (East-west, HPC (High Performance Computing), computer cluster, etc.) and influence the minimun latency that can be tolerated in the network.


    • Server to Switch Connectivity Solution

    • Storage to Switch Connectivity Solution



    • Switch to Switch Connectivity Solution


     COMPUFOX Solutions

    COMPUFOX  offers a comprehensive solution of optics and cables which supports your network from 1GbE to 100GbE. We have a great selection of 1000BASE-T/SX/LX SFP, BiDi SFP, 10GBASE-SR/LR SFP+, DWDM SFP+, whole series 40G QSFP+ optics and cables, as well as the 100G CFP2 and CFP4, etc. which help you solve the cost issue in fiber project. Especially the 40G QSFP+ optics, with the passive optic design, they can be compatible with all the equipment of all major brands. In addition, most of them are ready stock. See Links below:

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  • Introduction to Bi-Directional Transceiver Modules

    Almost all modern optical transceivers utilize two fibers to transmit data between switches, firewalls, servers, routers, etc. The first fiber is dedicated to receiving data from networking equipment, and the second fiber is dedicating to transmitting data to the networking equipment. But there is a type of fiber optic transceiver module called BiDi (Bi-Directional) transceiver to break this rule. What's BiDi transceiver? How does it work? And why people believe it will have broad market prospect? This tutorial will give you the answer.

    What's BiDi Transceiver?

    BiDi transceiver is a type of fiber optic transceivers which is used WDM (Wavelength Division Multiplexing) Bi-directional transmission technology so that it can achieve the transmission of optical channels on a fiber propagating simultaneously in both directions. BiDi transceiver is only with one port which uses an integral bidirectional coupler to transmit and receive signals over a single fiber optical cable. Thus, it must be used in pairs.

    How Does BiDi Transceiver Work

    The primary difference between BiDi transceivers and traditional two-fiber fiber optic transceivers is that BiDi transceivers are fitted with Wavelength Division Multiplexing (WDM) couplers, also known as diplexers, which combine and separate data transmitted over a single fiber based on the wavelengths of the light. For this reason, BiDi transceivers are also referred to as WDM transceivers.

    To work effectively, BiDi transceivers must be deployed in matched pairs, with their diplexers tuned to match the expected wavelength of the transmitter and receiver that they will be transmitting data from or to.

    For example, if paired BiDi transceivers are being used to connect Device A (Upstream) and Device B (Downstream), as shown in the figure below, then:

    Transceiver A's diplexer must have a receiving wavelength of 1550nm and a transmit wavelength of 1310nmTransceiver B's diplexer must have a receiving wavelength of 1310nm and a transmit wavelength of 1550nm
    Diplexers at Work in BiDi Optical Ethernet Transceivers

    Advantages of BiDi Transceivers

    The obvious advantage of utilizing BiDi transceivers, such as SFP+- BiDi and SFP-BiDi transceivers, is the reduction in fiber cabling infrastructure costs by reducing the number of fiber patch panel ports, reducing the amount of tray space dedicated to fiber management, and requiring less fiber cable.

    While BiDi transceivers (a.k.a. WDM transceivers) cost more to initially purchase than traditional two-fiber transceivers, they utilize half the amount of fiber per unit of distance. For many networks, the cost savings of utilizing less fiber is enough to more than offset the higher purchase price of BiDi transceivers.

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  • 40G QSFP+ Transceiver Modules and DAC/AOC Cables Installation Guide

    To install and remove the transceiver optics in a right way is very necessary to ensure the network to work stably and efficiently. Today, we are going to introduce an installation guide of QSFP transceivers and DAC/AOC cables in 40G network.

    40GbE QSFP+ Transceivers Overview

    40 Gigabit Ethernet (40GbE) aggregation switches are becoming more common in today's data centers. At the heart of the 40GbE network layer is a pair of transceivers connected by a cable. The transceivers are plugged into either network servers or a variety of components including interface cards and switches and connected via the cables such as OM3 and OM4 for multimode application. Additionally DAC (Direct Attach Copper) cables or AOCs (Active Optical Cables) are used for short interconnection as a more cost-effective alternative solution. QSFP+ (Quad Small Form-factor Pluggable Plus) is the most common 40GbE interface type, and also as a high-density 10GbE interface via QSFP+ breakout cables. QSFP+ interfaces a network device (switch, router, media converter or similar device) to a fiber optic or copper cable, supporting data rates from 4x10 Gbps and supports Ethernet, Fibre Channel, InfiniBand and SONET/SDH standards with different data rate options. Compared to CFP (C form-factor pluggable) transceiver modules, QSFP transceiver modules are more compact and more suitable for port-density application. The two basic interface specifications of QSFP+ modules respectively for multimode and single-mode applications are 40GBASE-SR4 and 40GBASE-LR4.

    40GBASE-SR4 QSFP+ Module

    The 40GBASE-SR4 QSFP+ module, conforming to the 802.3ba D3.2 (40GBASE-SR4) standard, provides a 40Gbps optical connection using MPO/MTP® optical connectors. This optical module integrates four data lanes in each direction with 40Gbps aggregate bandwidth and each lane can operate at 10.3125 Gbps. It is used in data centers to interconnect two Ethernet switches with 8 fiber parallel multimode fiber OM3/OM4 cables (transmission distance can be up to 100 meters using OM3 fiber or up to 150 meters using OM4 fiber).


    40GBASE-LR4 QSFP+ Module

    The 40GBBASE-LR4 QSFP+ module, conforming to the 802.3ba (40GBASE-LR4) standard, provides a 40Gbps optical connection using LC optical connectors. This optical module integrates four data lanes in each direction with 40Gbps aggregate bandwidth and each lane can operate at 10.3125 Gbps. It is most commonly deployed between data center or IXP sites with single-mode fiber up to 10 km.

     In addition, to satisfy a number of different objectives including support for MMF and SMF compatibility, there are other types of QSFP+ modules offered by different vendors.

    How to Install/Remove QSFP+ Transceivers and DAC/AOC Cables

    To protect a QSFP+ module or cable from ESD (electro-static discharge) damage, before installing or removing a QSFP+ module or cable, be remembered that always wear an ESD wrist strap and make sure that it makes good skin contact and is securely grounded (If you are using ESD gloves, wear the wrist strap outside the ESD glove).

    To Install or Remove a QSFP+ Transceiver Module

    There are two types of clasp designed for a QSFP+ transceiver module—plastic clasp or a metallic clasp. Here uses the metallic clasp type as an example.

    To Install a QSFP+ Transceiver Module

    Step 1. Remove the QSFP+ module from its antistatic container and remove the dust covers from the module optical connector.
    Step 2. Remove any rubber dust covers from the port where you are installing the QSFP+ module.
    Step 3. Pivot the clasp of the module up. (Skip this step if the clasp is plastic.)
    Step 4. Align the module with the port in the chassis, as shown in Figure 1.

    Figure 1. Aligning the module with the port
    Figure 1. Aligning the module with the port

    Step 5. Holding the module, gently push in the module until it is firmly seated in the port.(see Figure 2.)

    Figure 2. Install the QSFP+ module to port
    Figure 2. Install the QSFP+ module to port

    Step 6. Immediately attach the patch cord with MPO connector or duplex LC connector to the QSFP+ transceiver module.(see Figure 3.)

    Figure 3. Install the patch cord to the module
    Figure 3. Install the patch cord to the module

    Note: Install the dust plug for the transceiver module if you are not to install an optical fiber into it.

    To Remove a QSFP+ Transceiver Module

    Step 1. Remove the optical fiber if any.
    Step 2. Pivot the clasp of the module down to the horizontal position. (Skip this step if the clasp is plastic.)
    Step 3. Holding the module, gently pull the module out of the port. (Figure 4)
    Step 4. Place the QSFP+ transceiver into an antistatic bag.

    Figure 4. Remove the QSFP+ module
    Figure 4. Remove the QSFP+ module

    To Install or Remove a 40G QSFP+ Cable

    The installation and removal procedures are the same for QSFP+ DAC cables and QSFP+ AOC cables. Here uses a QSFP+ DAC cable as an example:

    To Install a QSFP+ DAC Cable

    Step 1. Align the QSFP+ transceiver module (with the clasp on top) at one end of the cable with the port in the chassis, as shown in Figure 5.
    Step 2. Horizontally and gently push in the module to fully seat it in the port.

    Figure 5. Installing a QSFP+ DAC cable
    Figure 5. Installing a QSFP+ DAC cable

    To remove a QSFP+ DAC Cable

    Step 1. Gently press and release the QSFP+ transceiver module.(see Figure 6.)
    Step 2. Holding the cable, gently pull the clasp on the cable to pull out the transceiver module.

    Figure 6. Removing a QSFP+ DAC cable
    Figure 6. Removing a QSFP+ DAC cable

    To Install or Remove a 40G QSFP+ to 4x10G SFP+ Cable

    40G QSFP+ to 4x10G SFP+ cable combines one 40G QSFP+ module on one end and four 10G SFP+ module on the other end. The installation and removal procedures of 40G QSFP+ connector are introdueced above. Here only introduced the installation and removal of 10G SFP+ module:

    To Install an SFP+ Transceiver Module

    Step 1. Align the module with the SFP+ port, with the golden plating facing the spring tab (see Figure 7.) in the SFP+ port. If the chassis has two rows of ports, the spring tab in a port is on the bottom in the upper row and on the top in the lower row.
    Step 2. Slightly press the module against the spring tab so you can push the module straight into the port.

    Figure 7. Installing an SFP+ transceiver module
    Figure 7. Installing an SFP+ transceiver module

    To Remove an SFP+ Transceiver Module

    Step 1. Press the module with your thumb, as shown by callout 1 in Figure 8.
    Step 2. Gently pull the clasp on the cable to pull out the transceiver module, as shown by callout 2 in Figure 8.

    Figure 8. Removing an SFP+ transceiver module
    Figure 8. Removing an SFP+ transceiver module

    Verifying the installation

    Execute the display transceiver interface command on the device to verify that the transceiver module or DAC/AOC cable is installed correctly. If the transceiver module and DAC/AOC cable information is displayed correctly, the installation is correct. If an error message is displayed, the installation is incorrect or the transceiver optics is not compatible.

    transceiver interface command


    As 40 GbE are widely deployed, 40G transceiver optics are ubiquitous. A good practice and correct installation are very important for 40G network system, not only to protect the 40G transceiver optics and device from damage, but also to ensure a stable performance for system. In addition, by executing the display transceiver interface command, we can verify whether the installation is correct. Of course, the premise is that the transceiver optics you use is fully compatible with your device. COMPUFOX offers a comprehensive line of high-compatible 40G transceiver optics, such as 40GBASE-SR4 QSFP+, 40GBASE-LR4 QSFP+ and 40G DACs and AOCs with competitive prices. See Links below:


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