Why Is Plenum Cable Important to High Density Data Centers?

FacebookTwitterGoogle+LinkedInRedditTumblrShare

In most terrible building or house fire disasters, combustible plastics (PVC) used in the wiring are always among the very things that contribute to the rapid spread of fire and toxic smoke. And the air conditioning systems even help the toxic smoke given off by the burning cables to spread throughout the building quickly. As for the high density data center with high speed computing equipment and large amount of plastic jacketed cables, it is crucial to take measures to reduce the damage in an unwanted fire. How to make the crucial data center a safer place? The high quality plenum cable (eg. MTP fiber) can be one of the best choices.

break-down of precision air conditioning system might lead to fire incident

The break-down of precision air conditioning system might lead to fire incident.

Plenum Cable for Data Center Environment

Plenum space is an area used for return of air circulation or air conditioning systems. In a data center, the spaces covered by the precision air conditioning unit are often necessary to deploy plenum products. They include not only plenum containment that separates cold aisle and hot aisle, but also plenum cables that meet the highest fire code requirements. Both electric cables and fiber optic cables are required to be plenum rated (CMP) when they are installed in inner walls and inner ceilings of data center buildings.

Cold aisle containment (left) and hot aisle containment (right) in a precision air conditioning unit.

Cold aisle containment (left) and hot aisle containment (right) in a precision air conditioning unit.

MTP Plenum Fiber: Get Safety and High Bandwidth at the Same Time

The integration of plenum jacket and MTP fiber is a perfect solution for high density data center applications. The safety feature of the plenum cable and the high fiber port count of MTP connector endow the data center with two essential components. By using MTP plenum cable, the possible danger that might be caused by cables located at cold aisle and hot aisle can be minimized when a fire incident occurs. In addition, the high bandwidth demands within a limited space in data center can be satisfied.

safe and high speed mtp plenum cable

Use MTP plenum cable to get safety and high bandwidth at the same time.

When buying MTP fibers, be sure to check if it is genuine plenum rated and the MTP connector should meet the physical connection standard for acceptable insertion loss. When burnt, plenum cable will give off little smoke, and the color of the smoke is light instead of dark. FS MTP plenum cables are made of Corning fiber and U.S. Conec MTP connector. They are all tested and guaranteed by 3D interferometry and the insertion loss is no more than 0.35 dB. No matter it is the plenum jacket, the inner fiber, the connector, or the end face geometry, they are all genuine parts and in high quality. They can be checked by any user without a problem.

FS high quality MTP plenum cable made of U.S. Conec connector and Corning fiber.

FS high quality MTP plenum cable made of U.S. Conec connector and Corning fiber.

Cost Comparison of 10G Leaf Switch and 40G Spine Switch

The growth of network users and the virtualized and automated trend in network have called for a great change in the macro network infrastructure. The “old” three-tier network architecture, namely core, aggregation and access, is quickly proved to be inefficient in modern complicated network environment. So what’s next to replace the outdated frame? After my research, the best I currently find is the flatter leaf-spine network architecture, which surpasses the traditional one with improved switch capacity and much lower latency. This blog will give the cost comparison of 10G leaf switch and 40G spine switch

three-tier network is outdated

In order to help buying a suitable switch when scaling the efficient leaf-spine architecture, I will compare some different brands’ 10G leaf switch (48*10G SFP+ and 6*40G QSFP+) and 40G spine switch (32*40G QSFP+) in this post. It should be noted that each switch price shown below is based on my own research, and I cannot promise that you can get one at the same price, since there are cases of discount, charged shipping, or tax. But you can take it as a reference. And welcome to add new information or to correct mistakes.

10G Leaf Switch (48*10G SFP+ and 6*40G QSFP+), switch capacity being 1.44Tbps.

Brand Model CPU ASIC NOS Online Base Price (US$)
Edge-Core AS5812-54X X86-64 Broadcom Trident2 Cumulus Linux $4,438.07 ~ $4,889.75
Agema AG7648 X86-64 Broadcom Trident2 Agema OS & OcNOSTM $5,995.00
Cisco Nexus 9372PX X86-64 Broadcom Trident2 Cisco Internetwork Operating System (IOS) $9,505.00 ~ $21,318.16
Dell S4048-ON X86-64 Broadcom Trident2 Cumulus Linux $2,250.00 ~ $2,850.00
Arista 7050SX-72Q X86-64 Broadcom Trident2 Arista Extensible Operating System (EOS) $21,408.95
Juniper QFX5100-48S X86-64 Broadcom Trident2 Juniper Operating System (JunOS) $24,299.00 ~ $25,942.00
Brocade VDX 6740 X86-64 Broadcom Trident2 Brocade Fabric OS $16,815.82 ~ $19,369.99
HPE Altoline 6920 X86-64 Broadcom Trident2 HPE Comware $11,209.66 ~ $12,792.00
Huawei CE6851 X86-64 Broadcom Trident2 Huawei Operating System (OS) $6,379.95 ~ $11,238.08

40G spine switch (32*40G QSFP+), switch capacity being 2.56 Tbps.

Brand Model CPU ASIC NOS Online Base Price (US$)
Edge-Core AS6712-32X X86-64 Broadcom Trident2 Cumulus Linux $7,571.95 ~ $14,124.16
Agema AG8032 X86-64 Broadcom Trident2 Agema OS & OcNOSTM $8,495.00
Cisco Nexus 9332PQ X86-64 Broadcom Trident2 Cisco IOS $17,617.21 ~ $18,673.15
Dell S6000-ON X86-64 Broadcom Trident2 Cumulus Linux $ 29,476.80
Arista 7050QX-32S X86-64 Broadcom Trident2 Arista EOS $24,208.84 ~ $27,988.95
Juniper QFX5100-24Q X86-64 Broadcom Trident2 JunOS $29,313.83 ~ $32,949.99
Brocade VDX 6940 X86-64 Broadcom Trident2 Brocade Fabric OS $21,546.46 ~ $24,036.81
HPE Altoline 6940 X86-64 Broadcom Trident2 HPE Comware $15,354.38 ~ $15,739.68
Huawei CE7850 X86-64 Broadcom Trident2 Huawei OS $13,737.60 ~ $23,000.00

These open networking leaf and spine switches are almost all adopting Broadcom Trident 2 chip and the Intel 64 processor, the major difference between them lies in the software. Some big brand switches deploy their own network operating system while some support licensed Cumulus Linux OS.

FS provides not only high performance 10G leaf switch (S9000-48S6Q, 48*10G SFP+ and 6*40G QSFP+) and 40G spine switch (S9000-32Q, 32*40G QSFP+) that have excellent Broadcom Trident 2 switching chip and licensed Cumulus Linux OS, and customers also enjoy the easiest addressing of both hardware and software problems. When you buy open networking switch at FS, you can also get certified optics and cables, and professional software support effortlessly and at low cost.

10G leaf switch

The base prices listed above do not include accessories like optics and fiber optic cables, or the software and hardware support cost. And only a few vendors I know can provide certified optics and cables, and expert software and hardware support at the same time. One-stop experience could only be found at vendors like Cumulus Networks (Cumulus Express service) and FS (Fiberstore). As you know that building a high performance networking is never only about switch, it would be better if simple and all-in-one approach could be provided in switch installation.

Differences Between Cloud Computing and Data Center

Many people may be confused about what is cloud computing and what is data center. They often ask questions like, “Is a cloud a data center?”, “Is a data center a cloud?” or “Are cloud and data center two completely different things?” Maybe you know your company needs the cloud and a date center. And you also know your data center needs the cloud and vice versa. But you just don’t know why! Don’t worry. This essay will help you have a thorough understanding of the two terms and tell you how they differ from each other. Let’s begin with their definition first.

What Is Data Center and Cloud Computing?
Difference between Cloud Computing and Data Center

The term “data center” can be interpreted in a few different ways. First, an organization can run an in-house data center maintained by trained IT employees whose job is to keep the system up and running. Second, it can refer to an offsite storage center that consists of servers and other equipment needed to keep the stored data accessible both virtually and physically.

While the term “cloud computing” didn’t exist before the advent of Internet. Cloud computing changes the way businesses work. Rather than storing data locally on individual computers or a company’s network, cloud computing entails the delivery of data and shared resources via a secure and centralized remote platform. Rather than using a company’s own servers, it places its resources in the hands of a third-party organization that offers such a service.

Cloud Computing VS. Data Center in Security
Cloud Computing VS. Data Center in Security

Since the cloud is an external form of computing, it may be less secure or require more work to ensure security than a data center. Unlike data centers, where you are responsible for your own security, you will be entrusting your data to a third-party provider that may or may not have the most up-to-date security certifications. If your cloud are placed on several data centers in different locations, each location will also need the proper measures to ensure the security.

A data center is also physically connected to a local network, which makes it easier to ensure that only those with company-approved credentials and equipment can access stored apps and information. The cloud, however, is accessible by anyone with the proper credentials anywhere that there is an Internet connection. This opens a wide array of entry and exit points, all of which need to be protected to make sure that data transmitted to and from these points are secure.

Cloud Computing VS. Data Center in Cost
Cloud Computing VS. Data Center in Cost

For most small businesses, cloud computing is a more cost-effective option than a data center. Because when you chose a data center, you have to build an infrastructure from the start and will be responsible for your own maintenance and administration. Besides, a data center takes much longer to get started and can cost businesses $10 million to $25 million per year to operate and maintain.

Unlike a data center, cloud computing does not require time or capital to get up and running. Instead, most cloud computing providers offer a range of affordable subscription plans to meet customers’ budget and scale the service to their actual needs. And data centers take time to build,  whereas cloud services are available for use almost immediately after registration.

Conclusion

Going forward, cloud computing services will become increasingly attractive with a low cost and convenient service. It creates a new way to facilitate collaboration and information access across great geographic distances while reducing the costs. Therefore, compared with the traditional data center, the future of cloud computing is definitely much brighter.

Are White Box Switches Equal to OEM Switches?

With a low cost and excellent performance, white box switch has been a hot topic in the past few years. However, the basic definition of white box switch is still vague and ambiguous as a result of various reasons. Firstly, no one has ever made an accurate and standard conception of white box switches before; secondly, manufacturer with different interests and demands will deliberately obscure the definition of white box switch; thirdly, people who are unaware of the truth of Internet tend to be wrongly informed, which also lead to chaos in its definition. Some even simply equate a white box switch with an OEM switch. So what is a white box switch exactly?

white box switch

How to Understand White Box Switches?

According to its literal meaning, white box switches refer to switches without a label. However, there exists a deep connotation in white box switches which means this kind of switches doesn’t focus on brand. Based on this core idea, to better understand white box switches, here we might as well divide them into the following three models:

  • Bare-mental switch. It is the fundamental type of white box switch with no network operating system loaded on them except a boot loader. Customers can purchase a software through a third party like Big Switch, Cumulus, and Pica8 or even write a software by themselves. They ask for hardware support from hardware vendors and software support from software vendors.
  • White box switch. In this model, the supplier will offer switches with both hardware and software (the supplier only provide one of them, either hardware or software, but they got the authority of another from their partners). So customers can seek support for both hardware and software from one supplier. Besides, there are options for customers to choose for both hardware and software.
  • OEM switches. The hardware and software of the switch are manufactured and provided by an OEM (original equipment manufacturer). These OEMs design and manufacture a switch as specified by another company to be rebranded or not branded. This kind of switch is also called white box switch by many people. And suppliers offering this service are called white box supplier, especially when the supplier is small and not well-known.
The Market for White Box Switches

With a wide choice of networking software based on low-cost, commodity hardware, white box switches are bound to have a vast market in the future. Also, with the deployment of SDN, there is an increasing interest in white box switches within the IT community. In the previous text, we have divided white box switches into three types. Next, I will analyze the market for white box switches based upon this classification.

The market for white box switches

  • Bare-mental switches have been most widely used with a customer group mainly from networking giants like Google, Facebook, and Microsoft. They purchase a bare-mental switch and develop networking software by themselves. In china, large companies like Baidu, Alibaba, Tecent, and JD also tried this model, with Baidu being the most successful example. The reason why these giants chose such a kind of white box switch is that they are confident and capable enough to handle the development and operation of the software for a switch. Besides, these major technology firm have an extremely large-scale network, which requires them to control the network completely by themselves.
  • The customers for the second type are mainly distributed abroad with only a few in China. They mainly come from large financial companies, international data corporation and some network operators, whose size may only behind those internet giants. Cost saving is the most important driving force for them to buy a white box switch. Also, part of these enterprises chose it just for the differentiated operating system provided by white box suppliers who are willing to satisfy their specific demands through customized service.
  • The customer for the third type is distributed both at home and abroad. Although the market for this part is smaller than the first two, it has the largest potential for its customer group involving a large number of VARs (value added resellers), system integrators, IT products providers and many medium-sized clients. They adopt a white box switch for varied reasons such as improving the production line and saving costs.
Summary

Through this essay, we can see clearly that white box switch is much more than an OEM switch and the latter can be classified as one kind of the former. With a lower cost, excellent performance and huge market potential, white box switch will definitely grow up as the mainstream for switch adoption.

The Evolution of Data Center Switching

Today, the traditional three-tier data center switching design has developed as a mature technology which had been widely applied. However, with the rapid growth in technology, the bottlenecks and limitations of traditional three-tier architecture keep emerging and more and more network engineers choose to give up such a kind of network architecture. So what’s the next best option for data center switching? The answer is leaf-spine network. For many years, data center networks have been built in layers that, when diagrammed, suggesting a hierarchical tree. As this hierarchy runs up against limitations, a new model is taking its place. Below, you will see a quick comparison between the two architectures, how they’ve changed and the evolution of data center switching.

Traditional Three-Tier Architecture

data center switching

Traditional three-tier data center switching design historically consisted of core Layer 3 switches, aggregation Layer 3 switches (sometimes called distribution Layer 3 switches) and access switches. Spanning Tree Protocol was used between the aggregation layer and the access layer to build a loop-free topology for the Layer 2 part of the network. Spanning Tree Protocol had a lot of benefits including a relatively easy implementation, requiring little configuration, and being simple to understand. Spanning Tree Protocol cannot use parallel forwarding paths however, it always blocks redundant paths in a VLAN. This impacted the ability to have a highly available active-active network, reduced the number of ports that were usable, and had high equipment costs.

The Fall of Spanning Tree Protoco

From this architecture, as virtualization started to grow, other protocols started to take the lead to allow for better utilization of equipment. Virtual-port-channel (vPC) technology eliminated Spanning Tree blocked ports, providing an active-active uplink from the access switches to the aggregation Layer 3 switches, and made use of the full available bandwidth. The architecture also started to change from the hardware standpoint by extending the Layer 2 segments across all of the pods. With this, the data center administrator can create a central, more flexible resource pool that can be allocated based on demand and needs. Some of the weaknesses of three-tier architecture began to show as virtualization continued to take over the industry and virtual machines needed to move freely between their hosts. This traffic requires efficiency with low and predictable latency. However, vPC can only provide two parallel uplinks which leads to bandwidth being the bottleneck of this design.

The Rise of Leaf-Spine Topology

Spine-and-Leaf-Topology-Data-Center-Switching

Leaf-spine topology was created to overcome the bandwidth limitations of three-tier architecture. In this configuration, every lower-tier switch (leaf layer) is connected to each of the top-tier switches (spine layer) in a full-mesh topology. The leaf layer consists of access switches that connect to servers and other devices. The spine layer is the backbone of the network and is responsible for interconnecting all leaf switches. Every leaf switch is connected to every spine. There can be path optimization so traffic load is evenly distributed among the spine. If one spine switch were to completely fail, it would only slightly degrade performance throughout the data center. Every server is only a maximum number of hops from any other server in the mesh, greatly reducing latency and allowing for a smooth vMotion experience.

Leaf-spine topology can also be easily expanded. If you run into capacity limitations, expanding the network is as easy as adding an additional spine switch. Uplinks can be extended to every leaf switch, resulting in the addition of interlayer bandwidth and reduction of oversubscription. If device port capacity becomes a concern, a new leaf switch can be added. This architecture can also support using both chassis switches and fixed-port switches to accommodate connectivity types and budgets. One flaw of the spine-and-leaf architecture, however, is the number of ports needed to support each leaf. When adding a new spine, each leaf must have redundant paths connected to the new spine. For this reason, the number of ports needed can grow incredibly quickly and reduces the number of ports available for other purposes.

Conclusion

Now, we are witnessing a change from the traditional three-tier architecture to a spine-and-leaf topology. With the increasing demand in your data center and east-west traffic, the traditional network topology can hardly satisfy the data and storage requirements. And the increasingly virtual data center environments require new data center-class switches to accommodate higher throughput and increased port density. So you may need to purchase a data center-class switch for your organization. Even if you don’t need a data center-class switch right now, consider it next year. Eventually, server, storage, application and user demands will require one. The best-value and cost-efficient data center switch for your choice at FS.com.

100G QSFP28 PAM4 or Coherent CFP?

The ever-increasing need for higher data rate in mobile data traffic, data centers and cloud services has pushed the access streams from 2.5Gb/s to 100Gb/s, and is demanding for 100Gb/s beyond without a stop. In today’s core network that has deployed 100G rates, there are QSFP28 optical transceivers including SR4, PSM4, CWDM4, LR4, ER4, etc., serving for a maximum 25km transmission distance. And there are 100G AOC, DAC and breakout cables generally for applications of tens of meters. 100G CFP/CFP2 modules including SR10, LR4 and ER4 support transmission distances of 150m to 40km. Until recent years, the telecom service providers are adopting new 100G DWDM technologies in their high capacity and long distance backbone applications. Coherent 100G DWDM transceivers are the first to be deployed for 100G long-haul applications, and then new technologies like PAM4 (Pulse Amplitude Modulation) are developed to meet lengths requirements for 100G metro network. This post is to discuss the issues on coherent and PAM4 100G DWDM transceivers.

Overview on 100G DWDM Transceivers

In the past few years, the adoption of 100G DWDM technologies is mainly focused on coherent DWDM optical transceivers, including CFP and CFP2. Until the year 2016, Inphi (a specialist in this area) offers pluggable 100G PAM4 QSFP28 DWDM transceivers to support 80km data center interconnect (DCI). The alternative for 100G DWDM coherent transceiver is given much attention. Besides, this new option for 100G DWDM transceiver also arouses hot discussion on which to choose. Knowing the characteristics and suited applications of them could help in selection.

QSFP28 PAM4 and Coherent CFP/CFP2

There are significant differences between QSFP28 PAM4 transceivers and coherent CFP/CFP2 transceivers, but they also have some relations in 100G applications. Contents below will go to details of these optical modules.

QSFP28 PAM4

Before the announcement of PAM4, binary NRZ (non-return to zero) modulation format is used for 40G and 100G long-haul transmission systems. PAM4 has four distinct levels to encode two bits of data, essentially doubling the bandwidth of a connection. Currently the single-wavelength PAM4 modulation scheme is considered the most cost-effective, efficient enabler of 100G and beyond in the data center. The 100G DWDM transceiver utilizing PAM4 signaling is in QSFP28 form factor. The advantage is that the customers who want to build an embedded DWDM network can use this transceiver directly in the switch. On this side, it is simple and cost-effective solution. But there are some prerequisites: it needs amplification to get out of the blocks and dispersion compensation to go beyond 5-6km. Therefore, a separate DWDM multiplexer with an amplification system and dispersion compensation is required to connect data canters together.

single wavelength PAM4 100G

In another case, if the QSFP28 PAM4 module is added to an existing DWDM network, it must be a network already having right dispersion compensation modules (DCMs) and amplification system in place; if it is not, changes are required when QSFP28 PAM4 is later added.

Coherent CFP

CFP digital coherent optics (DCO) have a high speed digital signal processing (DSP) chip built in. They do not require separate DCMs. This is what makes CFP different from QSFP28. Instead, they have electronic dispersion compensation built in. Although the built-in DSP requires more power and adds cost in components, it releases the switch vendors from adding DSPs to their equipment. Coherent CFPs enables transmission distance of more than 1000km between sites.

CFP2 analog coherent optic (ACO) is half the width of the CFP. Existing CFP2 coherent DWDM optical transceivers are analog and require a separate DSP on the host board to take the full advantages of the coherent features. So it is suited for switch vendors who have fitted such a DSP, but it adds additional cost and power consumption on the main board.

CFP2 digital coherent optic (DCO), expected to be released in the coming two years, is more optimized than CFP2 ACO in that it has built-in DSP. This component will open up to all switch vendors using CFP2 without DSP. With different coherent CFPs optional, customers can pay only for what they need when they need it.

QSFP28 PAM4 or Coherent CFP?

This really should depend on the applications. According to ACG research (an analyst and consulting firm that focuses on the service providers’ networking and the telecom industry), the 100G PAM4 solution and coherent DWDM solution, together with IEEE802.3ba, cover different portions of the optical fiber reach in the data center interconnect. So when deploying a long distance 100G DWDM network with DWDM transceivers, the required transmission distance and available equipment should be taken into consideration when choosing a suitable pluggable module.

IEEE, PAM4, OIF coherent optical reaches

Conclusion

Using pluggable transceivers for embedded DWDM, where the DWDM functionality is in the transceiver and not a separate DWDM converter platform, offers the ultimate solution in terms of cost and simplicity. Both QSFP28 PAM4 and coherent CFP/CFP2 are all suited to this approach. They can be used for embedded DWDM networking or as part of an existing DWDM installation. They all enable the advantages of pluggable modules: simple installation, easy spares handling, lower cost of ownership and quick return on invest.

Can I Use the QSFP+ Optics on QSFP28 Port?

100G Ethernet will have a larger share of network equipment market in 2017, according to Infonetics Research. But we can’t neglect the fact that 100G technology and relevant optics are still under development. Users who plan to layout 100G network for long-hual infrastructures usually met some problems. For example, currently, the qsfp28 optics on the market can only support up to 10 km (QSFP28 100GBASE-LR4) with WDM technology, which means you have to buy the extra expensive WDM devices. For applications beyond 10km, QSFP28 optical transceivers cannot reach it. Therefore, users have to use 40G QSFP+ optics on 100G switches. But here comes a problem, can I use the QSFP+ optics on the QSFP28 port of the 100G switch? If this is okay, can I use the QSFP28 modules on the QSFP+ port? This article discusses the feasibility of this solution and provides a foundational guidance of how to configure the 100G switches.

For Most Switches, QSFP+ Can Be Used on QSFP28 Port

As we all know that QSFP28 transceivers have the same form factor as the QSFP optical transceiver. The former has just 4 electrical lanes that can be used as a 4x10GbE, 4x25GbE, while the latter supports 40G ( 4x10G). So from all of this information, a QSFP28 module breaks out into either 4x25G or 4x10G lanes, which depends on the transceiver used. This is the same case with the SFP28 transceivers that accept SFP+ transceivers and run at the lower 10G speed.

QSFP can work on the QSFP28 ports

A 100G QSFP28 port can generally take either a QSFP+ or QSFP28 optics. If the QSFP28 optics support 25G lanes, then it can operate 4x25G breakout, 2x50G breakout or 1x100G (no breakout). The QSFP+ optic supports 10G lanes, so it can run 4x10GE or 1x40GE. If you use the QSFP transceivers in QSFP28 port, keep in mind that you have both single-mode and multimode (SR/LR) optical transceivers and twinax/AOC options that are available.

In all Cases, QSFP28 Optics Cannot Be Used on QSFP+ Port

SFP+ can’t auto-negotiate to support SFP module, similarly QSFP28 modules can not be used on the QSFP port, either. There is the rule about mixing optical transceivers with different speed—it basically comes down to the optic and the port, vice versa. Both ends of the two modules have to match and form factor needs to match as well. Additionally, port speed needs to be equal or greater than the optic used.

How to Configure 100G Switch?

For those who are not familiar with how to do the port configuration, you can have a look at the following part.

  • How do you change 100G QSFP ports to support QSFP+ 40GbE transceivers?

Configure the desired speed as 40G:
(config)# interface Ethernet1/1
(config-if-Et1/1)# speed forced 40gfull

  • How do you change 100G QSFP ports to support 4x10GbE mode using a QSFP+ transceiver?

Configure the desired speed as 10G:
(config)# interface Ethernet1/1 – 4
(config-if-Et1/1-4)# speed forced 10000full

  • How do you change 100G QSFP ports from 100GbE mode to 4x25G mode?

Configure the desired speed as 25G:
(config)# interface Ethernet1/1 – 4
(config-if-Et1/1-4)# speed forced 25gfull

  • How do you change 100G QSFP ports back to the default mode?

Configure the port to default mode:
(config)# interface Ethernet1/1-4
(config-if-Et1/1)# no speed

Note that if you have no experience in port configuration, it is advisable for you to consult your switch vendor in advance.

Conclusion

To sum up, QSFP+ modules can be used on the QSFP28 ports, but QSFP28 transceivers cannot transmit 100Gbps on the QSFP+ port. When using the QSFP optics on the QSFP28 port, don’t forget to configure your switch (follow the above instructions). To make sure the smooth network transmission, you need to ensure the connectors on both ends are the same and no manufacturer compatibility issue exists.

The Basics of 1000BASE-SX and 1000BASE-LX SFP

Gigabit Ethernet has been regarded as a huge breakthrough of telecom industry by offering speeds of up to 100Mbps. Gigabit Ethernet is a standard for transmitting Ethernet frames at a rate of a gigabit per second. There are five physical layer standards for Gigabit Ethernet using optical fiber (1000BASE-X), twisted pair cable (1000BASE-T), or shielded balanced copper cable (1000BASE-CX). 1000BASE-LX and 1000BASE-SX SFP are two common types of optical transceiver modules in the market. Today’s topic will be a brief introduction to 1000BASE-LX and 1000BASE-SX SFP transceivers.

1000BASE in these terms refers to a Gigabit Ethernet connection that uses the unfiltered cable for transmission. “X” means 4B/5B block coding for Fast Ethernet or 8B/10B block coding for Gigabit Ethernet. “L” means long-range single- or multi-mode optical cable (100 m to 10 km). “S” means short-range multi-mode optical cable (less than 100 m).

1000BASE-SX
1000BASE-SX is a fiber optic Gigabit Ethernet standard for operation over multi-mode fiber using a 770 to 860 nanometer, near infrared (NIR) light wavelength. The standard specifies a distance capability between 220 meters and 550 meters. In practice, with good quality fiber, optics, and terminations, 1000BASE-SX will usually work over significantly longer distances. This standard is highly popular for intra-building links in large office buildings, co-location facilities and carrier neutral internet exchanges. 1000BASE-SX SFP works at 850nm wavelength and used only for the purposed of the multimode optical fiber with an LC connector. 1000BASE-SX SFP traditional 50 microns of multimode optical fiber link is 550 meters high and 62.5 micron fiber distributed data interface (FDDI) multimode optical fiber is up to 220 meters. Take EX-SFP-1GE-SX as an example, its maximum distance is 550m with DOM support. The 1000Base-SX standard supports the multimode fiber distances shown in table 1.

1000Base-SX standard

1000BASE-LX
Specified in IEEE 802.3 Clause 38, 1000BASE-LX is a type of standard for implementing Gigabit Ethernet networks. The “LX” in 1000BASE-LX stands for long wavelength, indicating that this version of Gigabit Ethernet is intended for use with long-wavelength transmissions (1270–1355 nm) over long cable runs of fiber optic cabling. 1000BASE-LX can run over both single mode fiber and multimode fiber with a distance of up to 5 km and 550 m, respectively. For link distances greater than 300 m, the use of a special launch conditioning patch cord may be required. 1000BASE-LX is intended mainly for connecting high-speed hubs, Ethernet switches, and routers together in different wiring closets or buildings using long cabling runs, and developed to support longer-length multimode building fiber backbones and single-mode campus backbones. E1MG-LX-OM is Brocade 1000BASE-LX SFP that operates over a wavelength of 1310nm for 10 km.

1000BASE-LX SFP

Difference Between LX, LH and LX/LH
Many vendors use both LH and LX/LH for certain SFP modules, this SFP type is similar with the other SFPs in basic working principle and size. However, LH and LX/LH aren’t a Gigabit Ethernet standard and are compatible with 1000BASE-LX standard. 1000BASE-LH SFP operates a distance up to 70km over single-mode fiber. For example, Cisco MGBLH1 1000BASE-LH SFP covers a link length of 40km that make itself perfect for long-reach application. 1000BASE-LX/LH SFP can operate on standard single-mode fiber-optic link spans of up to 10 km and up to 550 m on any multimode fibers. In addition, when used over legacy multimode fiber type, the transmitter should be coupled through a mode conditioning patch cable.

Conclusion
1000BASE SFP transceiver is the most commonly used component for Gigabit Ethernet application. With so many types available in the market, careful notice should be given to the range of differences, both in distance and price of multimode and single-mode fiber optics. Fiberstore offers a large amount of in-stock 1000BASE SFP transceivers which are compatible for Cisco, Juniper, Dell, Finisar, Brocade, or Netgear in various options. If you have any requirement of our products, please send your request to us.

Related Article: Compatible SFP for Cisco 2960 Series Switches

Still Have Problems with Quanta LB4M and LB6M 10G Switches?

With the growth of virtualization, cloud-based services and applications like VoIP, video streaming and IP surveillance, various 10G switches with diverse functions spring out on the market. Quanta LB4M and LB6M 10G switches are two types popular 10G switches among them. However, there is few user manuals on the Internet, which brings inconveniences for users. This post intends to give a simple introduction to Quanta LB4M and LB6M 10G switches and some solutions for the common problems that may arise in their operating process.

Basis of Quanta LB4M and LB6M 10G Switches

The Quanta LB4M is a modular Gigabit Ethernet backbone switch designed for adaptability and scalability. This switch supports up to 48 Gigabit Ethernet ports to function as a central distribution hub for other switches, switch groups, or routers. And it offers 2 SFP+ interfaces for 10G port on the daughter board. While the Quanta LB6M switch provides 24 10GbE SFP+ ports and 4 1000BASE-T ports, which makes it more popular than LB4M. For these two switches, many users think highly of its performance. But there are also some passive remarks due to the limited documentation.

quanta lb4m & lb6m

Problem & Solution

If you have searched on the Internet, you will find that there are so many questions about Quanta LB4M and LB6M switches in all aspects like lack of instructive manuals, the operating issues, IP setup problems, etc. Here is a collection of several popular ones in discussion forums and blogs. Hope it will help you.

Quanta LB4M MAC Entry Problem

Use the LB4M in an active/passive configuration for SAN (Storage Area Networking). The two SAN nodes of the user have HA (fail over) and for that it uses a virtual IP which is moved between the two head nodes in case of failure. But the virtual IP MAC is missing from the LB4M switches “mac-addr-table”, which in turn leads to this virtual IP to be mirrored to all ports on that vlan.

Solution: right MAC (Media Access Control) mapping is the core of Ethernet switches. The first choice is to determine whether the MAC address of the switches is valid. Then pick a random address with the same 3-byte prefix as one of your physical MAC addresses and see if the switch accepts it. Another choice is to check the port security where the switch only accepts traffic from a single MAC address, either hard-coded in the config or the first one “seen” on that port.

LB4M Ports Are Deactivated and Backup Image Is Corrupt

Bought a Quanta LB4M and configured a management IP for the Web interface. After rebooting the switch as told, the screen showed that the crc-checksum for both the first and the backup image are corrupt, and another image is needed via the modem.

Solution: try to get upload an image via the modem to fix the problem. And then test it to check if the switch works.

Connect Dell 2848 with SFP to Quanta LB6M?

Dell 2848 switch has four SFP ports, while the Quanta LB6M has 24 10GbE SFP+ ports and 4 1000BASE-T ports. And other devices also need to be connected with. Then how to connect Dell 2848 with Quanta LB6M? The data center is currently running on a 1Gb Cat 6 cables.

Solution: using 10Gb SFP+ LC modules for the Quanta LB6M, 1Gb SFP LC modules for the Dell 2848 and then run MM fiber. Since SFP+ and SFP ports are not compatible, OEM services are another choice to solve this type of problem. FS.COM offers various kinds of customized service to meet customers’ different demands.

How to Avoid the Problems Mentioned Above?

It is undeniable that the Quanta LB4M and LB6M 10G switches are popular among users, which can be seen from the remarks in some forums. But since there is few instructive documents to describe these two types of switches, it will be difficult to solve the problems met in the operating process immediately. FS.COM supplies various kinds of 10G switches to meet the demand of Gigabit access or aggregation for enterprise networks and operators customers. Other 10G optics like 10G transceiver and 10G DAC & AOC are also available. Welcome to visit our website www.fs.com for more information.

How to Handle Challenges of CWDM Testing?

CWDM technology has proven itself to be a cost-effective and simplified method for network managers to optimize the existing infrastructure. The adoption of CWDM system into metro and regional network is constantly on the rise and it also extends the reach to the access networks. CWDM is becoming more widely accepted as an important transport architecture owing to its lower power dissipation, smaller size, and less cost. This article will focus on the challenges concerning CWDM testing, and provide several methods to help overcome them.

Basic Configurations of CWDM Network

CWDM configuration is usually based on a single-fiber pair: one fiber is for transmitting and the other for receiving. The following figure shows the most basic configuration of optical network with 4 channel CWDM MUX/DEMUX: it often delivers eight wavelengths, from 1471 nm to 1611 nm, with 20 nm apart. A CWDM architecture is quite simple. It only has passive components like multiplexers and demultiplexers, without any active elements such as amplifiers. However, using CWDM as a means of increasing bandwidth also brings network characterization and deployment challenges, which will be discussed in the following section.

cwdm basic configuration

Challenges and Solutions for CWDM Testing

The challenges of CWDM testing mainly lie in three phases: construction and installation, system activation and upgrade or troubleshoot. Here we provide solutions for each.

Challenge One: Construction and Installation

During construction and installation process, it is essential to conduct physical-layer tests on the fiber from the head-end to the destination. Single-ended testing with an OTDR is definitively an advantage as it optimizes labor resources. In this case, the objectives are to characterize the entire link (not only the fiber) to include the add-drop multiplexers (OADM) and to guarantee continuity up to the final destination. However, testing at standard OTDR wavelengths, such as 1310 nm and 1550 nm, cannot be done in such conditions as these wavelengths are filtered out at either OADM, never reaching the end destination. Then how to test such a link?

cwdm otdr testing

Solution: Adopting a specialized CWDM OTDR. With CWDM-tuned wavelength, the CWDM OTDR is capable of performing an end-to-end test by dropping each test wavelength at the correspondent point on the network, allowing the characterization of each part of the network directly from the head-end. Which is considered time and labor saving since one don’t have to access. It also helps to speed up the deployment process as the technician will test all drop fibers from a single location.

Challenge Two: System Activation

Since CWDM architecture is rather basic which contains no active components like amplifiers, the only things that can prevent proper transmission in a CWDM system are transmitter failure, sudden change in the loss created in an OADM or manual errors, bad connections for example. To deal with these problems, one has to look at the signal being transmitted.

Solution: A CWDM channel analyzer is ideal to handle this challenge. It works to quickly determine the presence or absence of each of the 16 wavelengths and their power levels. Many CWDM OADM have tap ports, which means that there is a port where a small portion of the signal is dropped. Taps are typically 20 dB weaker than the main signal. If these taps are not present, a CWDM analysis should be performed. It consists of unplugging the end user to use the main feed for the analysis. To be ready for all possibilities, a CWDM channel analyzer should cover a power range going as low as –40 dBm, while being able to test the entire wavelength range in the shortest time as possible.

Challenge Three: Upgrade or Troubleshoot

In the maintenance and troubleshoot phrase, when the network is live and a new wavelength is added, one should figure out two questions: is the link properly set up? And is my wavelength presents and well?

out-of-band testing of cwdm

Solution: Two approaches are available to check if a link is set up properly: a CWDM OTDR approach or an out-of-band approach. The CWDM OTDR approach is relatively simple when a new customer is added. With CWDM OTDR, one can perform CWDM testing without having to wait for the customer or to go to the cell tower sites. The wavelength can be turned on at the head-end. Which speed testing process greatly.

The OTDR and channel analyzer combo are also useful when a single customer has issues. The channel analyzer will reveal if the channel is indeed present and within power budget. If not, the CWDM OTDR can be used to test at that specific wavelength or an out-of-band 1650 nm OTDR test can be performed from the customer’s site to detect any anomalies on the link, all without disconnecting the head-end since the OADM will filter out the 1650 nm, therefore not affecting the remainder of the network.

Conclusion

CWDM testing challenges may be inevitable during each phase of the deployment, but with specialized equipment, these challenges can be overcomed completely. Tools including a CWDM OTDR, a CWDM channel analyzer and an out-of band OTDR are proved effective and valuable to reduce downtime and increase bandwidth at a minimum cost.