Are you doing Data Center Maintenance? Remember these 5 Points!

In this post, we are going to discuss some important factors you should keep in mind while planning and conducting your data center maintenance routine. Please note that the following guidelines are general in nature and relevant for most data centers regardless of the size and the technology being used.

Carrying on with data center maintenance brings plenty of benefits such as:

• Lesser unplanned downtimes
• Better safety
• Extended reliability
• Cut in energy consumption
• Extended equipment life
• Training opportunities (etc.)
• data center maintenance

1. Consult Equipment Manuals

Networking equipment used in data centers comes with vendor documents such as operation and maintenance manuals. These manuals contain all the relevant information about recommended maintenance timelines and practices. As someone in charge of a data center you have to ensure complete adherence to what is mentioned vendor documents. A proper preventive maintenance plan does guarantees not only system performance but also provides validation of your warranty.

2. Maintain Flawless & Up-to-date Documentation

You can enjoy a faster and easier to manage maintenance plan by writing down the procedures you are following, their frequency and the issues being faced. Documenting these procedures and their preservation on paper eliminates questions about what, where, why and when a maintenance activity took place. Thus, the onboarding process will be a lot smoother for new workers. Technicians will know what to do, by which procedure and how often.

Well-Kept documentation can assist you spot equipment or reliability related issues early resulting in the minimization of unnecessary downtimes. Last but not least, its documentation can save the day if a system breakdown does occur. Were there symptoms present before the failure? Was a skipped routine maintenance procedure part of the problem?

3. Test & Inspect

This is a great time to test and check UPS systems, power generators, batteries, routers, and switches ensure that they are working as expected. In this way, you will be able to minimize downtime by addressing the uncovered issues.

Here it is important to mention that a visual examination of connections and cabling should be a part of this process. Are cables labeled accurately and adequately? Does everything look neat and tidy? Is there a cable being twisted or bent? Is there a cable stack that requires to be taken care of?

4. Don’t Forget to Clean

Data center maintenance does not involve inspections and tests only — it calls for seemingly simple cleaning tasks also. Dust, for example, can turn into a bigger problem by blocking airflow and creating overheating issues. Regular removal of dirt can make equipment perform better and last longer. So, keep this point in mind during the planning phase and ensure that you have the right inventory of tools such as vacuum cleaners and brushes available.

5. Perform Safety Checks

Safety and security systems are not related to data center performance directly. However, data center maintenance offers you an excellent opportunity to check certain security features. Ensure that the entry and exit doors of the data center close and lock correctly. Are the surveillance and access control systems operating normally and capturing the information you expect and need? Are the emergency exit signs working as expected? Moreover, you should also ensure the health of firefighting equipment also. Most data center operators get their firefighting cylinders refilled during turnarounds.

Conclusion

Data center maintenance offers excellent opportunities for the operations and maintenance team. However, you should go with a comprehensive plan and well-fabricated schedule. By involving your team and following the guidelines as mentioned in the vendor’s documents, you will be able to end up with a replenished data center at your service.

HTFuture aim to be your Reliable Partner for different kinds of Compatible transceiver (QSFP28 for data center, QSFP+, SFP, XFP, SFP+, PON, Tunable, Copper, BIDI etc) DAC, AOC | OTN optical transmission system|DWDM Mux Demux|OADM | OTU | EDFA | NMS | DCM | OLP | OBP etc| 

More information, welcome to contact Ivy, contact Ivy. Email: sales6@htfuture.com Skype: live:sales6_1683

HTFuture team are ready and happy to assist you.

WDM-PON Network: An Efficient Solution for 5G Deployment

Driven by the rapid development of mobile communication industry, 5G network has boomed. However, 5G also faces some challenges such as the higher transmission bandwidth requirement. How to solve these problems? The WDM-PON network may be a better solution. This post will explain the advantages of WDM-PON technology and how it helps the 5G deployment.

Overview of WDM-PON Network & 5G

As it’s known to all, WDM-PON (Wavelength Division Multiplexing-Passive Optical Network) combines WDM technology with PON topology structure that allows operators to deliver high bandwidth to multiple endpoints over long distances. It includes some technologies, including colorless ONU technology, Auxiliary Management and Control Channel (AMCC), optical modules, OAM, and protection switching. With these key technologies, WDM-PON is regarded as an ideal solution which can meet the 5G requirements and has attracted great attention nowadays.

5G stands for the fifth generation of the wireless mobile network. It will be built on the foundation created by 4G LTE to allow people to send texts, make calls, and browse the web, etc. These upgraded 5G performance targets contain higher data rate, energy saving, higher-quality and massive device connectivity.

5G network

Why Choose WDM-PON for 5G Deployment?

As mentioned above, WDM-PON owns some useful technologies, which have unique advantages in 5G applications, including high bandwidth, low latency, low costs, fiber savings, easy maintenance, etc. The following will focus on introducing some of its merits.

High Bandwidth

The WDM-PON technology allows for traffic separation within the same physical fiber by different wavelengths. This results in a network that provides logical point-to-point connections over physical point-to-multipoint network topology. Moreover, AMCC signal modulation helps stack a management channel onto each wavelength. Therefore, the solution for carrying 5G front-haul over WDM-PON can offer a dedicated wavelength and extensive bandwidth resources to each user, saves time and increases transmission efficiency.

Low Latency

Having AMCC technology to deploy 5G, there is no need to use frame processing or dynamic bandwidth allocation (DBA) scheduling. This architecture provides low latency, low-frequency jitter, and flexible configuration of different front-haul interfaces.

Low Costs

With PON topology, it reduces the number of fiber needed by 5G front-haul networks with high site densities. The existing fiber infrastructure and equipment room are utilized, which saves the deployment and maintenance costs. What’s more, WDM-PON carries out an integrated front-haul/middle-haul (XHaul) transport network with the OLT. This OLT platform and the DU pool can be deployed in the same equipment room, which reduces the equipment construction costs. In addition, using the colorless technology of ONU in WDM-PON system results in low costs.

WDM-PON Network for 5G Deployment

Unlike the 4G which has the BBU and RRU two-level architectures, the 5G is constructed as three entities: CU (Centralized Unit), DU (Distribute Unit) and AAU (Active Antenna Unit). And 5G has three application scenario, including front-haul, middle-haul, and back-haul transmission. In the 5G Front-haul network, WDM-PON can be an efficient solution.

The following figure 1 shows the architecture of WDM-PON 5G front-haul network. Several RRUs and a DU are connected through a WDM-PON point-to-multipoint topology. The WDM-PON OLT is connected to the DU, CU, and ONU. ONU is also connected to RRUs. This OLT platform carries the front-haul traffic between the DU and RRUs as well as the middle-haul traffic between the DU and CU. In terms of the front-haul transmission or the connection between RRUs and DU, WDM-PON transmission interfaces play a significant role that enables the transparent user data transmission between them. In addition, the solution of applying WDM-PON to carry 5G is especially suitable for those operators who have to provide both wireless and wireline services in a greenfield scenario.

WDM-PON network

Summary

As boasting these advantages such as high capacity, low latency, cost-saving, etc., WDM-PON network is considered as an important solution for 5G. And the use of WDM-PON technology would become very common. To pave the way for the upcoming 5G network, HTFuture is striving to be the innovator in 5G communication. In fact, HTFuture has developed optical transceiver modules for WDM-PON network such as DWDM SFP+. If you have any needs, welcome to visit www.htfuture.com

HTFuture aim to be your Reliable Partner for different kinds of Compatible transceiver (QSFP28, QSFP+, SFP, XFP, SFP+, PON, Tunable, Copper, BIDI etc) | OTN optical transmission system|DWDM Mux Demux|OADM | OTU | EDFA | NMS | DCM | OLP | OBP etc| More information, welcome to contact Ivy, contact Ivy. Email: sales6@htfuture.com Skype: live:sales6_1683

HTFuture team are ready and happy to assist you.

What are the differences between GPON, XG-PON and XGS-PON?

Specification Differences Between 10G GPON and GPON

XG-PON, 10-Gigabit-capable passive optical network, provides asymmetric 10G transmission (Maximum downstream line rate: 9.953 Gbit/s, Maximum upstream line rate: 2.488 Gbit/s ).

XGS-PON, 10-Gigabit-capable symmetric passive optical network, provides symmetric 10G transmission (Maximum downstream line rate: 9.953 Gbit/s, Maximum upstream line rate: 9.953 Gbit/s ).

The following table lists specification differences between the two technologies.

HTFuture aim to be your Reliable Partner for different kinds of Compatible transceiver (QSFP28, QSFP+, SFP, XFP, SFP+, PON, Tunable, Copper, BIDI etc) | OTN optical transmission system|DWDM Mux Demux|OADM | OTU | EDFA | NMS | DCM | OLP | OBP etc| 

More information, welcome to contact Ivy, contact Ivy. Email: sales6@htfuture.com Skype: live:sales6_1683

HTFuture team are ready and happy to assist you.

Overview of PON Network

PON has now became a popular network technology all over the globe. It first came in to being in 1995. The International Telecommunication Union (ITU) standardized two initial generations of PON — APON and BPON. And the advancement of PON network has never stopped. Until now, the recent PON standard of NG-PON2 has been put forward in 2015. With the maturity of PON, people are more easily accessible to networks today. But what does PON exactly mean?

 What’s the composition of PON network? The following part will give you the answer.

PON, also known as passive optical network, is a technology in telecommunication that implements a point-to-multipoint (P2MP) architecture. Unpowered fiber optic splitters are used to enable a single optical fiber to serve multiple end-points such as customers instead of providing individual fibers between the central office (hub) and customer. According to different terminations of PON, the network system can be divided into fiber-to-the-home (FTTH), fiber-to-the-curb (FTTC), fiber-to-the-curb (FTTB), etc. To be specific, a PON is made up of an optical line terminal (OLT) at the service provider’s hub and a number of optical network units (ONUs) or optical network terminals (ONTs) near end users. And “passive” is just used to describe that no power requirement or active electronic component is included for transmitting signals in the system.

Types of PON Network

Here are some types of PON that have been used throughout the years:

1) APON

Its full name is asynchronous transfer mode (ATM) passive optical network. As the original PON system, APON uses ATM technology to transfer data in packets or cells of a fixed size. In APON, downstream transmission is a continuous ATM stream at a bit rate of 155 Mbps or 622 Mbps. Upstream transmission is in the form of bursts of ATM cells at 155 Mbps.

2) BPON

BPON, also known as broadband PON, is the improved version of APON. It adopts wavelength division multiplexing (WDM) for downstream transmission with the transmission rate up to 622 Mbps. It also provides multiple broadband services such as ATM, Ethernet access and video distribution. Today, BPON is more popular than APON.

3) EPON

EPON or Ethernet PON uses the Ethernet packets instead of ATM cells. Upstream and downstream rates of EPON are able to achieve up to 10 Gbps. It is now widely applied to FTTP or FTTH architecture to serve multiple users. With the advantages of scalability, simplicity, multicast convenience and capability of providing full service access, many Asian areas adopt EPON for their networks.

4) GPON

Gigabit PON is the development of BPON. It supports various transmission rates with the same protocol. The maximum data rate of downstream is 2.5 Gbps and upstream is 1.25 Gbps. It is also widely used for FTTH networks. But compared with EPON, its burst sizes and physical layer overhead are smaller.

Advantages of PON

• Low cost, simple maintenance, flexible extensibility and easy to upgrade. And no need for power during transmission saves a lot for long-term management.
• Using pure media network avoids the interference of lightning and electromagnetism. Thus PON network is suitable for areas under harsh conditions.
• Low occupancy of central office resources, low initial investment and high rate of return.
• As the P2MP network, PON is able to provide a large range of service to plenty of users.

Conclusion

PON network is for sure an effective solution for multiple network users. EPON and GPON are the most commonly deployed PON systems at present. Since people have been seeking for higher bandwidth provisioning, the capability of transmission will be greatly improved in the near future.

HTFuture aim to be your Reliable Partner for different kinds of Compatible transceiver (QSFP28, QSFP+, SFP, XFP, SFP+ etc) | OTN optical transmission system|DWDM Mux Demux|OADM | OTU | EDFA | NMS | DCM | OLP | OBP etc| More information, welcome to contact Ivy, contact Ivy. Email: sales6@htfuture.com Skype: live:sales6_1683

HTFuture team are ready and happy to assist you.

How Much Do You Know About OADM

The OADM, or optical add drop multiplexer, is a gateway into and out of a single mode fiber. In practice, most signals pass through the device, but some would be “dropped” by splitting them from the line. Signals originating at that point can be “added” into the line and directed to another destination. An OADM may be considered to be a specific type of optical cross-connect, widely used in wavelength division multiplexing systems for multiplexing and routing fiber optic signals. They selectively add and drop individual or sets of wavelength channels from a dense wavelength division multiplexing (DWDM) multi-channel stream. OADMs are used to cost effectively access part of the bandwidth in the optical domain being passed through the in-line amplifiers with the minimum amount of electronics.

OADMs have passive and active modes depending on the wavelength. In passive OADM, the add and drop wavelengths are fixed beforehand while in dynamic mode, OADM can be set to any wavelength after installation. Passive OADM uses WDM filter, fiber gratings, and planar waveguides in networks with WDM systems. Dynamic OADM can select any wavelength by provisioning on demand without changing its physical configuration. It is also less expensive and more flexible than passive OADM. Dynamic OADM is separated into two generations.

A typical OADM consists of three stages: an optical demultiplexer, an optical multiplexer, and between them a method of reconfiguring the paths between the optical demultiplexer, the optical multiplexer and a set of ports for adding and dropping signals. The optical demultiplexer separates wavelengths in an input fiber onto ports. The reconfiguration can be achieved by a cross connection panel or by optical switches which direct the wavelengths to the optical multiplexer or to drop ports. The optical multiplexer multiplexes the wavelength channels that are to continue on from demultipexer ports with those from the add ports, onto a single output fiber.

Physically, there are several ways to realize an OADM. There are a variety of demultiplexer and multiplexer technologies including thin film filters, fiber Bragg gratings with optical circulators, free space grating devices and integrated planar arrayed waveguide gratings. The switching or reconfiguration functions range from the manual fiber patch panel to a variety of switching technologies including microelectromechanical systems (MEMS), liquid crystal and thermo-optic switches in planar waveguide circuits.

CWDM and DWDM OADM provide data access for intermediate network devices along a shared optical media network path. Regardless of the network topology, OADM access points allow design flexibility to communicate to locations along the fiber path. CWDM OADM provides the ability to add or drop a single wavelength or multi-wavelengths from a fully multiplexed optical signal. This permits intermediate locations between remote sites to access the common, point-to-point fiber message linking them. Wavelengths not dropped, pass-through the OADM and keep on in the direction of the remote site. Additional selected wavelengths can be added or dropped by successive OADMS as needed.

HTFuture provides a wide selection of specialized OADMs for WDM system. Custom WDM solutions are also available for applications beyond the current product designs including mixed combinations of CWDM and DWDM.

HTFuture aim to be your Reliable Partner for different kinds of Compatible transceiver (QSFP28, QSFP+, SFP, XFP, SFP+ etc) | OTN optical transmission system|DWDM Mux Demux|OADM | OTU | EDFA | NMS | DCM | OLP | OBP etc| More information, welcome to contact Ivy, contact Ivy. Email: sales6@htfuture.com Skype: live:sales6_1683

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Differences Between Pre-Amplifier, Booster Amplifier and In-line Amplifier

Transmission distance has always been a key factor during deployment of fiber optic network. DWDM technologies, which are considered as the most cost-effective ways to increase the network capacity over long transmission distance, have been widely applied in our telecommunication network. To further extend transmission distance of optical signals transmission from the DWDM fiber optic transceivers, optical amplifiers are usually used in the DWDM network. Different types of optical amplifiers have been invented to meet the signal amplifying requirements at different situations. This post will introduce the differences between the three most commonly used optical amplifier: pre-amplifier, booster amplifier and in-line amplifier.

Basics of Optical Amplifier

In the past, if you want to extend the transmission distance of DWDM network, optical regenerator station is required to be installed in the fiber link every 80km to 100km. The regenerator station will electronically regenerate the optical signals to overcome the power loss and ensure that the optical signal can be detected at the receiver end. However, this requires a lot of money and is not easy to upgrade the whole network.

With optical amplifier, things become much easier. The optical amplifier can enlarge the optical signals without the regeneration. In addition, the network upgrading is more cost-effective with optical amplifier. Each optical amplifier has an important factor which is operation gain measured in dB. The operation gain of the optical amplifier should be carefully calculated to ensure the network performance. Pre-amplifier, booster amplifier and in-line amplifier are used in different places in the fiber optic network. And they support different operation gain according to the whole network requirement.

Pre-Amplifier, Booster Amplifier and In-line Amplifier

Pre-Amplifier is usually installed at the receiver end of the DWDM network to amplify the optical signal to the required level to ensure that it can be detected by the receiver. The following picture shows a typical diagram for a duplex 10G DWDM network which can support 80km. A pre-amplifier is installed at each receiving end of this network. There will be great power loss after the optical signal goes through the 80km optical fiber. Then, pre-amplifier installed at the receiver end is necessary. Generally, a pre-amplifier should offer high gain to ensure that the optical signal is detectable.

Booster Amplifier is installed in the transmitting end of the fiber optic network, which can amplifier the amplify the optical signal launched into the fiber link. It is usually used in DWDM network where the multiplexer attenuates the signal channels. The following picture shows a 10G DWDM network using booster amplifier (BA) at the transmitting end and pre-amplifier (PA) at receiving end. Thus, this 10G DWDM network can support a transmission distance much longer than the above mentioned one. Please note, a DCM (Dispersion Compensation Module) is added in this network to further ensure the transmission quality. A booster amplifier usually provides low gain and high output power.

In-line Amplifier is easy to understand. The gain provided by the pre-amplifier and booster amplifier might not be enough due to the optical loss caused by long haul transmission. In-line amplifier is installed in the fiber optic link every 80–100km as shown in the following picture. It has moderate gain and has similar output power to those of booster amplifier.

Conclusion

Optical amplifier can help to amplifier the optical power during long haul transmission to ensure that the receiver can detect the optical signal without error. Three amplifiers are commonly used in DWDM network. Booster amplifier is used to amplifier optical power at the transmitting end and pre-amplifier is placed at the receiver end. If the transmission distance is longer than 150km or have great power loss during transmission, in-line amplifier is suggested to be installed every 80km to 100k in the fiber optic link. The gain of these amplifiers should be carefully calculated during practical use. Kindly visit DWDM EDFA Amplifier page for more details.

HTFuture aim to be your Reliable Partner for different kinds of Compatible transceiver (QSFP28, QSFP+, SFP, XFP, SFP+ etc) | OTN optical transmission system|DWDM Mux Demux|OADM | OTU | EDFA | NMS | DCM | OLP | OBP etc| More information, welcome to contact Ivy, contact Ivy. Email: sales6@htfuture.com Skype: live:sales6_1683

HTFuture team are ready and happy to assist you.

CWDM modules'​ applications

Recently, some of our customers want to know more about the CWDM modules’ applications. Here we share some of CWDM knowledge to you, hope these can be helpful for your business!

1. What is CWDM modules?

With the CWDM optical transceiver, different wavelength can be transmitted by only one core. And it’s receiver can receive signal from 1270nm-1610nm.

2. Where is the CWDM modules can be used?

As the below picture, the CWDM modules can be used in kind of solutions.

3.What is the MUX/DEMUX?

A: We often transmit and receive information with optical fibers. Because the optical fiber can help us sharing the information fastly, saving time and improving efficiency.

On the other hand, it also needs to use lots of optical fibers, so in order to save optical fibers. We use MUX/DEMUX, it will help us concentrate the different wavelengths of information on one optical fiber.

Then spread them to the different switch when they need to be used.

4.How many channels can be used in CWDM MUX/DEMUX?

A: 18 channels, from 1270nm-1610nm.(1270nm, 1290nm, 1310nm, 1330nm, 1350nm, 1370nm, 1390nm,1410nm,1430nm, 1450nm, 1470nm, 1490nm,1510nm, 1530nm, 1550nm, 1570nm, 1590nm,1610nm.)

It includes forward wavelength(1270nm-1450nm, it’s usually used to low rate, like 1.25G ), backward wavelength(1470nm-1610nm, it’s usually used to high rate, like 2.5G, 10G)

5.How do they work together?

The CWDM Modules were inserted into switches, and between the modules and MUX/DEMUX, they connect with patch cords. Because of the MUX/DEMUX, we can save lots of optical fibers.

6. What do you need in a normal solution?

a. Switches: More than 2. (Depends on what’s the application you working for.)

b. CWDM Modules(Dual fiber): 16

c. MUX-DEMUX: 2

d. Patch cords: 32 & 1 testing patch cord(with an attenuator.)

e. Optical fiber: 1

Base on different applications, the solutions are different. It involved the switch type, MUX/DEMUX channel number, etc.

In a word, If you can tell us the project you are preparing(application), or where will the MUX/DEMUX(CWDM modules) be used, we can offer you the most suitable solution you need.

For more detailed information, please visit www.htfuture.com

HTFuture aim to be your Reliable Partner for different kinds of Compatible transceiver (QSFP28, QSFP+, SFP, XFP, SFP+ etc) | OTN optical transmission system|DWDM Mux Demux|OADM | OTU | EDFA | NMS | DCM | OLP | OBP etc| More information, welcome to contact Ivy, contact Ivy. Email: sales6@htfuture.com Skype: live:sales6_1683

HTFuture team are ready and happy to assist you.

What are the differences between 25G DAC and AOC cable?

25G Ethernet has been hitting the web world at a sudden rate and may eventually become the fastest IEEE Ethernet standard ever completed.

25G cable is divided into 25G SFP28 direct attach cable and 25G SFP28 active optical cable, both of them can transmit data at 25Gbps. What are the differences between them?

HTFuture will focus on the differences between the two cables.

What is a 25G Direct Attach Cable?

25G DAC cable using silver conductor and foam insulation core, it has good attenuation performance and low delay performance, which make the signal transmission is correct, and can increase the transmission speed, is a short connection solution instead of the optical transceiver, the price is much cheaper than the same type of optical transceiver, in short distance connection applications has been widely welcomed.

What is a 25G Active Optical Cable?

25G AOC cable can be overcome the bandwidth limitation of traditional high-speed cable, and the 25G active optical cable can provide an ideal alternative solution for high-speed cable and short-distance SFP28 optical module, and the signal is more complete and higher performance. It is widely used in high-speed, high-density, and low-power data center networks.

What is difference in structure between 25G Direct Attach Cable and 25G Active Optical Cable?

The 25G DAC is made up of a copper cable and a fiber-optic transceivers at both ends. The connector is similar to the interface of the optical transceiver.But the connector modules on high-speed cables do not have expensive lasers, which greatly reduces the cost of short-range applications.

The 25G AOC consists of optical transceiver devices at both ends and composed of different length of OM3 or OM4 multimode optical fibers.The transceiver devices at both ends can provide the function of photoelectric conversion and optical transmission. This function ensures data transmission stability and application flexibility.

Compares to the 25G DAC, What are the advantages of 25G AOC?

1. The volume of 25G active optical cable is one-half of 25G high-speed cable, the weight is a quarter of it, so 25G active optical cable is much lighter than 25G high-speed cable;

2. 25G active optical cable also has better transmission performance and bit error rate, and the BER can reach 10–15;

3. 25G active optical cable has lower transmission power on the system link.

The 25G technology is the foundation of the 100G(4*25Gbps) Ethernet standard. Compared with the 40G technology, the 25G technology can provide higher port density and reduce cost, so the 25G technology has a promising prospect.

With the rapid development of 25G Ethernet technology, HTFuture has introduced two types of cables, 25G SFP28 DAC and 25G SFP28 AOC to meet the 25G network needs of customers. You can also select our 25G DAC cable or 25G AOC cable customized service according to your needs. 

For customized details, you can email to Ivy from HTFuture: sales6@htfuture.com.

How to Select Direct Attach Cable?

In today’s telecommunication market, high-qualified cables are always sought by users to satisfy the increasing demands of greater bandwidth and the growing amount of data transmission. As a result, direct attach cables have been designed to meet these requirements. Maybe you are not familiar with them and can’t determine which kind of direct attach cable is applicable for your networking servers. There is no need to worry. This post will introduce direct attach cables in details.

Definition of Direct Attach Cable

Direct attach cable (DAC), a kind of optical transceiver assembly, is a form of high speed cable with “transceivers” on either end used to connect switches to routers or servers. DACs are much cheaper than the regular optics, since the “transceivers” on both ends of DACs are not real optics and their components are without optical lasers. In storage area network, data center, and high-performance computing connectivity, they are preferable choice for their low cost, low power consumption and high performances.

Classifications of Direct Attach Cable

Direct attach cables can be divided into several types according to different standards. By Ethernet transmission rate and construction standard, 10G SFP+ cables, 40G QSFP+ cables, and 120G CXP cables are available. Classification according to the number of connectors is also feasible. Most DAC assemblies have one connector on each end of the cable, but there is a special kind of DAC assembly which may have 3 or 4 connectors on one end of the cable. Take QSFP+ to 4 SFP+ Passive Copper Direct Attach Breakout Cable for example, it features a single QSFP+ connector (SFF-8436) rated for 40-Gb/s on one end and 4 SFP+ connectors (SFF-8431), each rated for 10-Gb/s, on the other.

Based on material of cables used, there are direct attach copper cables and active optical cables.

Direct Attach Copper Cable — Direct attach copper cables are designed in either active or passive versions. The former provides signal processing electronics to avoid signal issue, thus to improve signal quality. What’s more, the former can transmit data over a longer distance than the latter which offers a direct electrical connection between corresponding cable ends. Nowadays, direct attach copper cables still have a place in market owing to their interchangeability, low cost and various data rates.

Active Optical Cable — Active optical cable (AOC) is one form of DAC. It integrates multi-mode optical fiber, fiber optic transceivers, control chip and modules. It uses electrical-to-optical conversion on the cable ends to improve speed and distance performance of the cable while mating with electrical interface standard. Compared with direct attach copper cable, its smaller size, electromagnetic interference immunity, lower interconnection loss and longer transmission distance make it popular among consumers.

Direct attach cables allow for greater bandwidth cost-effectively. As for which kind or kinds of DACs are suitable for network connectivity, it depends on specific situations. HTFuture supplies above-mentioned high-qualified DACs. Also, DACs can be customized in HTFuture to meet your different requirements.

More information about DACs, Welcome to conatct Ivy from HTFuture:

Email: sales6@htfuture.com Skype: live:sales6_1683

HTFuture team are ready and happy to assist you.

CWDM Network: Technology Overview and Common Applications

Fiber exhaust is an inevitable problem constantly faced by carriers since the demand for higher speed bandwidth never ceases. The ever-improving wavelength division multiplexing (WDM) technology nowadays is increasingly used to boost network capacity, enabling carriers to deliver more services over their existing fiber infrastructure. CWDM, as one form of the mature WDM technologies, is a perfect fit for access networks and metro/regional networks. This article addresses the CWDM fundamentals and its common applications, and how CWDM helps to maximize network capacity effectively.

CWDM Technology at a Glance

Coarse wavelength division multiplexing (CWDM) came into prominence as a cost-effective alternative to maximize network capacity in the access, metro and regional network segments. It gains in more popularity in area with a relatively moderate traffic growth due to its simple deployment and low cost. ITU-T G.694.2 defines 18 wavelengths for CWDM transport ranging from 1270 to 1610 nm, spaced at 20 nm apart. But 8 wavelength in the 1470–1610nm band is mostly used since there exist high attenuation in the 1270–1450 nm band. This technology shines out in access network deployments by obtaining the advantages of flexible add-drop capacity and network design simplicity.

Common Applications of CWDM

After going through the basics of CWDM technology, this section will further explain its common applications. CWDM is primarily deployed in two areas: metropolitan and access networks. Let’s see how they could benefit from applying it.

Fiber Exhaust Relief

Fiber exhaust appears to be a severe problem that carriers endeavor to solve, especially for some metropolitan networks where data traffic increases continuously. Adding CWDM to the original optical network presents a cost-efficient and simple approach to this problem. In this case, carriers can add new services over a existing single optical fiber, while not interrupting service for existing customers. This solution is ideally suited for carriers that desires to increase the already installed network capacity without new fiber construction.

Enterprise LAN and SAN Connection

When interconnecting geographically dispersed Local Area Networks (LANs) and Storage Area Networks (SANs), CWDM rings and point-to-point links offer an optimum option. It is beneficial to integrate multiple Gigabit Ethernet, 10 Gigabit Ethernet and Fiber Channel links over a single fiber for CWDM point-to-point applications or for ring applications.

Adoption in Metro Networks With Lower Cost

4 channel CWDM system offers an ideal solution for smaller metro/regional markets which demand for moderate traffic growth. This configuration can expand the available capacity four times over an existing network, enabling less deployment cost than the commonly adopted 8 channel system. Meanwhile, the scalability of this 4 channel system also allows carriers to upgrade to 8 channel systems when the need occurs.

Central Office to Customer Premise Interconnection

Coarse WDM system is also well-fitted for metro-access applications such as Fiber to the Building (FTTB). Let’s take the most widely used 8 channel CWDM network for example, it is capable of delivering 8 independent wavelength services from the Central Office (CO) to multiple business offices located in the same building.

Combining With PON

Passive Optical Network (PON) is a point-to-multipoint optical network to deliver bandwidth to the last mile. It is cost-effective because it uses passive devices (splitters for example) instead of expensive active electronics. The issue exists in PON is that the amount of bandwidth they can support is rather limited. Since CWDM serves to multiple bandwidth, when combining it with PON, each additional lambda becomes a virtual point-to-point connection from a central office to an end user. If one end user in the original PON deployment needs his own fiber, adding CWDM to the PON fiber creates a virtual fiber for that user. Once the traffic is switched to the assigned lambda, the bandwidth taken from the PON is now available for other end users, so the access system can maximize fiber efficiency.

Conclusion

CWDM has clearly become the preferred method for increasing the bandwidth of metro/regional and optical access networks quickly, simply and at lowest cost. And it has proven to be sufficiently robust and reliable for upgrading the optical network to accommodate future growth. Hope this article could help to get a better understanding of coarse WDM technology.

HTFuture can provide you the full range of CWDM DWDM products that you need. If there is any inquiry, just let me know please.

Ivy: sales6@htfuture.com Skype: live:sales6_1683

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Reference Guide to Optical Transceiver Testing

As an integral part of the entire network, optical transceiver plays a significant role in deciding the overall performance and reliability of the network. The importance of optical transceiver testing therefore cannot be overestimated. Currently, since an increasing number of optical transceivers employed in networks is provided by third party suppliers, to ensure their compatibility and interoperability becomes more of a concern than ever. Well, this article is here to help you deliver effective optical transceiver testing.

Optical Transceiver Overview

Generally, an optical transceiver consists of a transmitter and a receiver. When a transmitter is connected with a receiver but the system doesn’t achieve your desired bit-error-ratio (BER), is there something wrong with the transmitter or the receiver? The transmitter and the receiver can affect each other, thus, specifications should guarantee that any receiver will interoperate with a worst-case transmitter, and any transmitter will provide a signal with sufficient quality such that it will interoperate with a worst-case receiver.

Precisely, defining worst case is often a complicated task. If a receiver needs a minimum level of power to achieve the system BER target, then that level will dictate the minimum allowed output power of the transmitter. If the receiver can only tolerate a certain level of jitter, this will be used to define the maximum acceptable jitter from the transmitter. In general, there are four basic steps for optical transceiver testing, as shown in the following picture, which mainly includes the transmitter testing and receiver testing.

Transmitter Testing

Transmitter parameters may include wavelength and shape of the output waveform while the receiver may specify tolerance to jitter and bandwidth. As an vital part in transceiver testing, testing a transmitter usually consists of two steps:

1. The input signal used to test the transmitter must be good enough. Measurements of jitter and an eye mask test must be performed to confirm the quality using electrical measurements.

 An eye mask test is a common method to view the transmitter waveform and provides a wealth of information about overall transmitter performance.

2. The optical output of the transmitter must be tested using several optical quality metrics such as a mask test, OMA (optical modulation amplitude), and Extinction Ratio.

Receiver Testing

Testing the receiver also serves as an essential part in transceiver testing. similarly, there are two steps:

1. Unlike testing the transmitter, in which case one must ensure that the input signal is of good quality, testing the receiver involves sending in a signal of poor enough quality. In this case, a stressed eye represents the worst case signal shall be created. This is an optical signal, and must be calibrated using jitter and optical power measurements.

2. The last step is to test the electrical output of the receiver. There are three basic categories we should follow:

• A mask test, which ensures a wide enough eye opening. The mask test is usually accompanied by a BER (bit error ratio) depth.
• Jitter budget test, which tests for the amount of certain types of jitter.
• Jitter tracking and tolerance, which tests the ability of the internal clock recovery circuit to track jitter within its loop bandwidth.

Conclusion

Complicated as it is, fiber optic transceiver testing is also an indispensable step to ensure overall network performance. As basic eye-mask test offers an effective and commonly used option for transmitter testing, testing the receiver can be more complex and requires more testing methods. A wide variety of fiber optic transceivers are available in Htfuture that are compatible with major brands on the market, such as Cisco, HP, IBM, Juniper, etc. Moreover, each fiber optic transceiver has been tested with the original-brand switch to ensure its high performance and superior quality. For more detailed information, please visit www.htfuture.com

HTFuture aim to be your Reliable Partner for different kinds of Compatible transceiver (QSFP28, QSFP+, SFP, XFP, SFP+ etc) | OTN optical transmission system|DWDM Mux Demux|OADM | OTU | EDFA | NMS | DCM | OLP | OBP etc| More information, welcome to contact Ivy, contact Ivy. Email: sales6@htfuture.com Skype: live:sales6_1683

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CWDM SFP vs DWDM SFP - Which One Suits You Better?

Overview of CWDM SFP

CWDM SFP is a kind of optical transceiver that utilizes CWDM technology. Similar with traditional SFP module, the CWDM SFP is a hot-swappable input/output device. It plugs into an SFP port or slot of a switch or router and links the port with the fiber-optic network. CWDM SFP transceiver modules make use of the SFP interface for connecting the equipment and use dual LC/PC fiber connector interface for connecting the optical network.

It is well known that CWDM SFP modules come in 8 wavelengths covering from 1470 nm to 1610 nm. Color markings on the devices identify the wavelength to which the Gigabit Ethernet channel is mapped.The following picture lists the CWDM SFPs with their wavelengths and color codes.

DWDM SFP Overview

DWDM (Dense Wavelength-Division Multiplexing) SFP transceivers are used as part of a DWDM optical network to provide high-capacity bandwidth across an optical fiber network, which is a high performance, cost-effective module for serial optical data communication applications up to 4.25Gb/s. There are 32 fixed-wavelength DWDM SFPs that support the International Telecommunications Union (ITU) 100-GHz wavelength grid. An inner structure of DWDM SFP is shown below.

Application

CWDM SFP transceiver is widely used in optical communications for both telecommunication and data communication. It is designed for operations in Metro Access Rings and Point-to-Point networks using Synchronous Optical Network (SONET), SDH (Synchronous Digital Hierarchy), Gigabit Ethernet and Fibre Channel networking equipment. The DWDM SFP can be also used in DWDM SONET/SDH (with or without FEC), but for longer transmission distance like 200km links and Ethernet/Fibre Channel protocol traffic for 80km links.

Which SFP Module Type Should You Choose: DWDM vs CWDM?

From a low-cost point of view, the CWDM SFP module is inexpensive than DWDM SFP. It provides a convenient and cost-effective solution for the adoption of Gigabit Ethernet and Fibre Channel. On the other hand, the key in selecting DWDM vs CWDM SFP modules lies in the differences between CWDM and DWDM. They refer to different methods of splitting up the light. For example, CWDM uses broader spacing between channels, allowing for inexpensive SFPs, and DWDM uses denser channel spacing, which allows for more wavelengths to be used on a single fiber. DWDM is typically used in large optical networks over the longer distance. Thus if you are looking for SFP modules over long distance and with better scalability, DWDM SFP module is the ideal choice.

Conclusion

I hope this brief introduction to DWDM vs CWDM SFP modules is helpful for you to make a choice in selecting them. Based on the Cisco CWDM SFPs, HTFuture CWDM SFPs are multi-rate transceivers, supporting data rates from 100 Mbps up to 4 Gbps. Besides, they support transfer distance at 20–40km, 40–80km and 80–120km in different colors, diversely satisfy the requirements of clients. All the DWDM SFP modules meet the requirements of the IEEE802.3 Gigabit Ethernet standard. They are suitable for interconnections in Gigabit Ethernet and Fibre Channel environments.

HTFuture aim to be your Reliable Partner for different kinds of Compatible transceiver (QSFP28, QSFP+, SFP, XFP, SFP+ etc) | OTN optical transmission system|DWDM Mux Demux|OADM | OTU | EDFA | NMS | DCM | OLP | OBP etc| More information, welcome to contact Ivy, contact Ivy. Email: sales6@htfuture.com Skype: live:sales6_1683

HTFuture team are ready and happy to assist you.