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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.

    DWDM OVER CWDM NETWORK

    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.

    Fiberstore

    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.

    Fiberstore

    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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  • Polarity and MPO Technology in 40/100GbE Transmission

    It have been proved that reducing cable diameters and increasing connection densities offered by fiber links would be extremely valuable during installation in constrained space, like data center, large enterprise equipment rooms, central office, etc. With the market turning to 40/100G transmission, to reduce congestion during cabling and make it easier to organize equipment cable runs, the network designers turns to MPO/MTP technology and components for today's duplex fiber transmission. Then, network designers face another challenge which is how to assure the proper polarity of these array connections using MPO/MTP components from end-to-end.

    Traditionally, a fiber optic link requires two fibers for full duplex communications. It is very important to ensure that the equipment on the link are connected properly at each end. However, when the link contains two or more fibers, maintain the correct polarity across a fiber network become more complex, especially when using multi-fiber MPO components for high data rate transmission. Luckily, pre-terminated MPO components adopt humanized design for polarity maintenance and the TIA 568 standard provides three methods for configuring systems to ensure that proper connections are made. This article will introduce polarity in MPO system and 40/100GbE polarization connectivity solutions in details.

    Polarity in MPO Components

    To maintain the correct polarity in MPO systems, the property of the components of MPO systems should be understood firstly. This part will introduce the basic components that are used in MPO system.

    MPO Connector: To understand the polarity in 40/100 GbE transmission, the key of MPO technology—MPO connector should be first introduced. MPO connector usually has 12 fibers. 24 fibers, 36 fibers and 72 fibers are also available. Each MTP connector has a key on one of the flat side added by the body. When the key sits on the bottom, this is called key down. When the key sits on the top, this is referred to as the key up position. In this orientation, each of the fiber holes in the connector is numbered in sequence from left to right and is referred as fiber position, or P1, P2, etc. A white dot is additionally marked on one side of the connector to denote where the position 1 is. (shown in the following picture) The orientation of this key also determines the MTP cable's polarity.

    MPO connector

     

    MPO Adapter: MPO (male) connectors are mated to MPO(female) connectors using a MPO adapter. As each MPO connector has a key, there are 2 types of MPO adapters:

    Type A—key-up to key-down. Here the key is up on one side and down on the other. The two connectors are connected turned 180° in relation to each other.Type B—key-up to key-up. Here both keys are up. The two connectors are connected while in the same position in relation to each other.

     

    MPO adapter

     

    MPO Cables: MPO trunk cable with two MPO connectors (male/female) on both side of the cable serves as a permanent link connecting the MPO modules to each other, which is available with 12, 24, 48, 72 fibers.

    MPO harness cable, which is terminated with a male/female connector on the MPO side and several duplex LC/SC connectors on the other side, provides a transition from multi-fiber cables to individual fibers or duplex connectors.

    MPO Cassette: Modular MPO cassette is enclosed unit that usually contains 12 or 24-fiber factory terminated fan-outs inside. It enables the user to take the fibers brought by a trunk cable and distribute them to a duplex cable with a MPO connector (at the rear) to the more common LC or SC interface (on the front side). The following is a MTP cassette with 6 duplex LC interface and a MTP connector.

    MTP cassette

    Three Cables for Three Polarization Methods

    The three methods for proper polarity defined by TIA 568 standard are named as Method A, Method B and Method C. To match these standards, three type of MPO truck cables with different structures named Type A, Type B and Type C are being used for the three different connectivity methods respectively. In this part, the three different cables will be introduced firstly and then the three connectivity methods.

    MPO Trunk Cable Type A: Type A cable also known as straight cable, is a straight through cable with a key up MPO connector on one end and a key down MPO connector on the opposite end. This makes the fibers at each end of the cable have the same fiber position. For example, the fiber located at position 1 (P1) of the connector on one side will arrive at P1 at the other connector. The fiber sequence of a 12 fiber MPO Type A cable is showed as the following:

    Type A cable

    MPO Trunk Cable Type B: Type B cable (reversed cable) uses key up connector on both ends of the cable. This type of array mating results in an inversion, which means the fiber positions are reversed at each end. The fiber at P1 at one end is mated with fiber at P12 at the opposing end. The following picture shows the fiber sequences of a 12 fiber Type B cable.

    Type B cable

    MPO Trunk Cable Type C: Type C cable (pairs flipped cable) looks like Type A cable with one key up connector and one key down connector on each side. However, in Type C each adjacent pair of fibers at one end are flipped at the other end. For example, the fiber at position 1 on one end is shifted to position 2 at the other end of the cable. The fiber at position 2 at one end is shifted to position 1 at the opposite end etc. The fiber sequence of Type C cable is demonstrated in the following picture.

    Type C cable

    Three Connectivity Methods

    Different polarity methods use different types of MTP trunk cables. However, all the methods should use duplex patch cable to achieve the fiber circuit. The TIA standard also defines two types of duplex fiber patch cables terminated with LC or SC connectors to complete an end-to-end fiber duplex connection: A-to-A type patch cable—a cross version and A-to-B type patch cable—a straight-through version.

    duplex patch cable

    The following part illustrates how the components in MPO system are used together to maintain the proper polarization connectivity, which are defined by TIA standards.

    Method A: the connectivity Method A is shown in the following picture. A type-A trunk cable connects a MPO module on each side of the link. In Method A, two types of patch cords are used to correct the polarity. The patch cable on the left is standard duplex A-to-B type, while on the right a duplex A-to-A type patch cable is employed.

    Method A

    Method B: in Connectivity Method B, a Type B truck cable is used to connect the two modules on each side of the link. As mentioned, the fiber positions of Type B cable are reversed at each end. Therefore standard A-to-B type duplex patch cables are used on both sided.

    Method B

    Method C: the pair-reversed trunk cable is used in Method C connectivity to connect the MPO modules one each side of the link. Patch cords at both ends are the standard duplex A-to-B type.

    Method C

    Upgrade to 40/100GbE With Correct Polarity

    The using of MPO/MTP connectors for 40/100G transmission is achieved with multimode fiber by transmitting multiple parallel 10G transmissions that will then be recombined when received. This method has been standardized. The following is to offer 40G transmission solution and 100G respectively.

    40G Transmission Connectivity

    The 40G transmission usually uses 12-fiber MPO/MTP connectors. There are eight lanes within twelve total positions being employed for transmitting and receiving signals. Looking at the end face of the MPO/MTP connector with the key on top, the four leftmost positions are used to transmit, the four rightmost positions are used to receive, the four in the center are unused. The following picture shows the optical lane assignments. (Tx stands for Transmit, Rx stands for Receive) This approach would transmit 40G using for parallel 10G lanes in each direction according to 40GBase-SR4.

    40G transmission

    100G Transmission Connectivity

    The 100G transmission over multimode requires a total of 20 fibers, 10 for transmitting and 10 for receiving. There are three options which is introduced as following:

    The first method is to use a 24-fiber MPO/MTP connector with the top center 10 positions allocated for receiving and the bottom 10 position allocated for transmitting,as shown in the following figure. This method is recommended by IEEE.

    100G transmission

    The second option is to use two 12-fiber MPO/MTP connectors side by side. The 10 positions in the center of the connector on the left are used for transmitting and the center 10 positions of the left are used for receiving.

    100G transmission

    The third way of 100G transmission also uses two 12-fiber MPO/MTP connectors, but it uses the stacked layout as showed in the following figure. The ten center positions of the top connector are used for receiving and the ten center position of the bottom are used for transmitting.

    100G transmission

    Understand Polarity in 40/100G

    Any transmit position should be connected to its own receive position. Here's an analogy to illustrate: Think of ball players. You have pitchers & catchers. For 10G transmission, Pitcher 1 needs to throw to Catcher 1, Pitcher 2 to Catcher 2 and so on. (showed on the left side of the following picture) For 40/100G, any pitcher can throw to any catcher.(showed on the right side of the following picture)

    10/40/100G polarity understanding

    But if you've got two catchers looking at each other as showed in the following picture, there isn't a whole lot happening.

    wrong polarity

    Conclusion

    Network designer using MPO/MTP components to satisfy the increasing requirement for higher transmission speed, during which one of the big problems—polarity, can be solved by selecting the right types of MPO cables, MPO connectors, MPO cassette and patch cables. Consider the polarity method to be used and selecting the correct MPO/MTP components to support that methods, the proper solution for 40/100G transmission would be achieved with high density and flexibility and reliability.

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  • Standards and Recommendations for Fiber Optic Systems

    Many international and national standards govern optical cable characteristics and measurement methods. Some are listed below, but the list is not exhaustive. Releases are subject to change.

    International Standards

    Two main groups are working on international standards: International Electrotechnical Commission (IEC) and International Telecommunication Union (ITU).

    IEC: The IEC is a global organization that prepares and publishes international standards for all electrical, electronic, and related technologies, which serve as a basis for national standardization.

    The IEC is composed of technical committees who prepare technical documents on specific subjects within the scope of an application in order to define the related standards. For example, the technical committee TC86 is dedicated to fiber optics, and its subcommittees SC86A, SC86B, and SC86C focus on specific subjects such as: SC86A: Fibers and CablesSC86B: Fiber Optic Interconnecting Devices and Passive ComponentsSC86C: Fiber Optic Systems and Active Devices
    ITU: The ITU is an international organization that defines guidelines, technical characteristics, and specifications of telecommunications systems, networks, and services. It includes optical fiber performance and test and measurement applications and consists of three different sectors: Radiocommunication Sector (ITU-R)Telecommunication Standardization Sector (ITU-T)Telecommunication Development Sector (ITU-D)

     

    National Standards

    In addition to the international standards, countries or union of countries define their own standards in order to customize or fine tune the requirements to the specificity of their country.

    European Telecommunications Standards Institute

    The European Telecommunications Standards Institute (ETSI) defines telecommunications standards and is responsible for the standardization of Information and Communication Technologies (ICT) within Europe. These technologies include telecommunications, broadcasting, and their related technologies, such as intelligent transportation and medical electronics.

    Telecommunication Industries Association / Electronic Industries Alliance

    The Telecommunication Industries Association (TIA) provides additional recommendations for the United States. TIA is accredited by the American National Standards Institute (ANSI) to develop industry standards for a wide variety of telecommunications products. The committees and subcommittees define standards for fiber optics, user premises equipment, network equipment, wireless communications, and satellite communications.

    NOTE: There are many other standard organizations that exist in other countries.

     

    Fiber Optic Standards

    By IEC: IEC 61300-3-35: Fibre Optic Connector End Face Visual InspectionIEC 60793-1 and -2: Optical Fibers (includes several parts)IEC 60794-1, -2, and -3: Optical Fiber Cables
    By ITU: G.651: Characteristics of 50/125 μm Multimode Graded-index Optical FiberG.652: Characteristics of Single-mode Optical Fiber and CableG.653: Characteristics of Single-mode Dispersion Shifted Optical Fiber and CableG.654: Characteristics of Cut-off Shifted Single-mode Optical Fiber and CableG.655: Characteristics of Non-zero Dispersion Shifted Single-mode Optical Fiber and CableG.656: Characteristics of Non-zero Dispersion Shifted Fiber for Wideband TransportG.657: Characteristics of a Bending Loss Insensitive Single-mode Fiber for Access Networks

     

    Test and Measurement Standards

    Generic Test Standards: IEC 61350: Power Meter CalibrationIEC 61746: OTDR CalibrationG.650.1: Definition and Test Methods for Linear, Deterministic Attributes of Single-mode Fiber and CableG.650.2: Definition and Test Methods for Statistical and Non-linear Attributes of Single-mode Fiber and Cable
    PMD Test Standards: G.650.2: Definition and Test Methods for Statistical and Non- linear Attributes of Single-mode Fiber and CableIEC 60793 1-48: Optical Fibers—Part 1-48: Measurement Methods and Test Procedures—Polarization Mode DispersionIEC/TS 61941: Technical Specifications for Polarization Mode Dispersion Measurement Techniques for Single-mode Optical FiberIEC 61280-3/TIA/TR-1029: Calculation of PolarizationTIA 455 FOTP-124A: Polarization Mode Dispersion Measurement for Single-mode Optical Fiber and Cable Assemblies by InterferometryTIA 455 FOTP-113: Polarization Mode Dispersion Measurement of Single-mode Optical Fiber by the Fixed Analyzer MethodTIA 455 FOTP-122A: Polarization Mode Dispersion Measurement for Single-mode Optical Fiber by the Stokes Parameter MethodTIA TSB-107: Guidelines for the Statistical Specification of Polarization Mode Dispersion on Optical Fiber CablesTIA 455-196: Guidelines for Polarization Mode Measurements in Single-mode Fiber Optic Components and DevicesGR-2947-CORE: Generic Requirements for Portable Polarization Mode Dispersion (PMD) Test SetsIEC 61280-4-4: Polarization Mode Dispersion Measurement for Installed LinksTIA 445 FOTP-243: Polarization Mode Dispersion Measurement for Installed Single-mode Optical Fibers by Wavelength-scanning OTDR and State of Polarization Analysis
    CD Test Standards: G.650.1: Definition and Test Methods for Linear, Deterministic Attributes of Single-mode Fiber and CableIEC 60793 1-42: Optical Fibers—Part 1-42: Measurement Methods and Test Procedures—Chromatic DispersionIEC 61744: Calibration of Fiber Optic Chromatic Dispersion Test SetsTIA/EIA FOTP-175-B: Chromatic Dispersion Measurement of Single-mode Optical FibersGR-761-CORE: Generic Criteria for Chromatic Dispersion Test SetsGR-2854-CORE: Generic Requirements for Fiber Optic Dispersion Compensators
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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
     
    Preparations

    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

    Conclusion

    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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  • T-Mobile becomes number one US smartphone channel

    Written by Scott Bicheno  Telecoms.com

    T-Mobile

    Disruptive US operator T-Mobile has become the leading sales channel for smartphones in the US, according to new research from Counterpoint.

    T-Mobile overtook Verizon to take the number one smartphone sales spot, having been a distant fourth just two years ago. This change is viewed as indicative of a broader change in the way smartphones are being purchased in the US, with the cost of devices increasingly uncoupled from the service contracts and, if needed, paid for via conventional financing arrangements.

    The US market has undergone significant shifts in the power of the different sales channels with the move to unsubsidized plans,” said Neil Shah of Counterpoint. “The growth of T-Mobile through its different ‘Uncarrier’ moves, the removal of subsidies and enticing subscribers with ‘Simple Choice’ & ‘Jump’ plans, has helped the operator to become the top smartphone sales channel in the USA.

    Samsung and Apple together captured almost two-thirds of the total smartphone shipments share at T-Mobile, with Samsung leading. However, it will be an uphill task for T-Mobile to maintain this lead ahead of Verizon and continue to attract millions of subscribers to its network. The move to unsubsidized and unlocked has also boosted demand in the open channel, which continued to contribute close to 10% of the total shipments in Q1 2016.”

    Conterpoint US smartphones slide 2

    US smartphone sales on the whole declined by 4% year-on-year due to the maturity of the market (most people already have a smartphone) and a lengthening on the upgrade cycle. The latter factor will be a direct result of the shift in buying habits as fewer consumers are being prompted to upgrade their subsidized phones by the renewal of their postpaid contracts.

    “The US market decelerated due to softness in Apple iPhone demand and iPhone SE demand not materializing until Q2 2016,” said Jeff Fieldhack of Counterpoint. “Carriers continued to push subscribers to non-subsidy plans as for the first time more than half of the combined subscriber base of the top four carriers are now on non-subsidized plans. This is a significant shift from the subsidy-driven model just ten to twelve quarters ago. This has changed the basis of competition in US mobile landscape.

    “The focus has shifted to creating more value for the consumer, instead of being device-driven. Unsubsidized device sales have educated consumers that flagship smartphones are costly. This has led to a temporary softness in the device upgrade cycle; the in-carrier upgrade run rate continues to be in 5-6% range per quarter. Handset manufacturers will continue to push hardware and marketing limits to entice subscribers to not defer upgrading.”

     

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