Category Archives: Fiber Cabling

GLC-LH-SM vs SFP-GE-L: What’s the Difference?

GLC-LH-SM and SFP-GE-L are two Cisco 1000BASE-LX/LH Ethernet transceivers. Due to the similar mode and performance such as supporting distance and working wavelength, users are often confused with Cisco GLC-LH-SM and SFP-GE-L when they are choosing these SFP modules. Then, what’s the difference between Cisco GLC-LH-SM and SFP-GE-L? This post intends to give a simple explanation of GLC-LH-SM vs SFP-GE-L.

GLC-LH-SM vs SFP-GE-L

Specifications of GLC-LH-SM and SFP-GE-L
GLC-LH-SM SFP Module

Cisco GLC-LH-SM is a hot-swapple optical transceiver that supports the maximum data rate of 1Gbps. It’s compatible with the IEEE 802.3z 1000BASE-LX standard, and can operate on standard single-mode fiber optic link spans of up to 10 km and up to 550 m on any multimode fibers.

Modules Interface Wavelength Tx power Receiver Sensitivity DOM Support Temperature Range
Cisco GLC-LH-SM LC duplex 1310nm -9.5 ~ -3dBm < -23dBm No 32℉to 158℉
(0℃ to 70℃)
SFP-GE-L SFP Module

SFP-GE-L transceiver has many similarities with GLC-LH-SM transceiver. It is also a Cisco 1000BASE-LX/LH Ethernet transceiver that designed for Gigabit Ethernet applications. This 1000BASE-LX/LH SFP, compatible with the IEEE 802.3z 1000BASE-LX standard, and can operate on standard single-mode fiber optic link spans of up to 10 km and up to 550 m on any multimode fibers.

Modules Interface Wavelength Tx power Receiver Sensitivity DOM Support Temperature Range
Cisco SFP-GE-L LC duplex 1310nm -9.5 ~ -3dBm < -23dBm Yes 23℉ to 185℉(-5℃ to 85℃)

Notes: no matter GLC-LH-SM or SFP-GE-L modules, mode conditioning patch cables are required when they are used for 1000BASE-LX/LH applications over FDDI-grade, OM1, and OM2 fiber cables.

GLC-LH-SM vs SFP-GE-L: What’s the Difference?

From the Cisco official notes, Cisco original GLC-LH-SM SFP and SFP-GE-L transceiver have been no longer for sale since March 8, 2013. But this doesn’t affect the market of these two SFP modules. Many users still choose to use them. As mentioned above, GLC-LH-SM and SFP-GE-L are easy to be confused. In fact, it’s not difficult to tell from them.

The first big difference between the two SFP modules is SFP-GE-L SFP supports DOM (digital optical monitoring) while GLC-LH-SM module doesn’t. DOM is an important function available on fiber optic transceiver. It allows users to monitor parameters of modules, such as optical output power, optical input power, temperature, laser bias current, and transceiver supply voltage, in real time, offering users more convenience when using optical modules. Another difference is the operating temperature range. The temperature range of Cisco GLC-LH-SM SFP is 32℉to 158℉(0℃ to 70℃), while the extended operating temperature range of SFP-GE-L module is 23℉ to 185℉ (-5℃ to 85℃).

GLC-LH-SM vs SFP-GE-L: Which One to Select?

From the contents above—GLC-LH-SM vs SFP-GE-L, we can draw a conclusion that GLC-LH-SM and SFP-GE-L nearly can be used as the same one type module sometimes, but their existing differences still differ them from some applications. For example, the WS-SUP32-8GE-3B does not support DOM SFP modules like the SFP-GE-L while supporting GLC-LH-SM SFP. Therefore, buying the suitable one for your devices when choosing from the two modules. As noted above, these two modules are end-of-sale in 2013. However, FS.COM provides these two modules at a cheap price. And other types of compatible optical transceivers are available too. Every optic module in FS.COM is 100% tested to ensure fully compatible. More details, please visit www.fs.com.

Advantages and Disadvantages of OM5 Fiber in Data Center

As the continuously increased bandwidth demand, the types of fiber patch cable are also updating quickly. OM5 fiber cable, also known as WBMMF (wideband multimode fiber), has arrived to meet the growing bandwidth requirements. However, there are different opinions on whether the adoption of OM5 fiber will benefit today’s data center. This post will focus on the advantages and disadvantage that OM5 brings for data centers.

om5 patch cable

Trends in Data Center Deployment

With the cloud computing and web services continuing to drive bandwidth need, data rates grow from 10G, 40G to 100G and beyond in many data center networks. According to the Cisco global cloud index, nearly 99 percent of global traffic will pass through data centers by 2020. That means higher bandwidth, faster services and greater access are required for data center deployments. Therefore, advanced technologies including fiber patch cable and optical transceivers will be needed for performance-improving in data centers.

Will OM5 Fiber Benefit Data Center?

OM5 fiber is a new generation of multimode fiber. It was just standardized in several months ago. Different from OM1, OM2, OM3 and OM4, OM5 fiber is designed to work over a wide range of wavelengths between 850 nm and 950 nm. And it supports SWDM (shortwave wavelength division multiplexing) technology which can reduce fiber counts in optical transmission. Here are the advantages and disadvantages of OM5 fiber cable in data center.

om5 fiber cable

Advantages

Firstly, it cannot deny that the emergence of OM5 is to meet the high bandwidth challenges. At this point, OM5 will definitely benefit data centers in some degree. The main advantages are in the following part.

Compatibility—OM5 cable has the same fiber size of OM4 and OM3, which means OM5 is fully compatible with OM3 and OM4 fiber. In other words, OM5 cabling supports all legacy applications in existing data center infrastructures. If a service provider wants to use OM5 for high speed data center, big changes will not be needed for existing cabling.

Distance—multimode patch cord is often the first choice for short reach connections. As we know, OM4 patch cord can support link length up to 100m with 100G-SWDM4 transceivers. While OM5 can extend the reach to 150m with the same types of fiber optic transceivers, providing another better choice for data center optimization.

Cost—when it comes to data center building, the cost is an important parameter to consider. OM5 cable is beneficial for data center deployments. Compared to single mode fiber cable (SMF), multimode fiber cable (MMF) is more cost-effective, because in most data centers, short reach connection are common. Besides, OM5 provides optimal support of emerging SWDM applications which reduce the amount of fibers needed for high speed transmissions.

Disadvantages

Each coin has two sides. Though OM5 fiber cable can benefit data center building, there are still some problems at present. It’s known to us that OM5 has just been standardized earlier this year. Even though many optical vendors have introduced OM5 fiber patch cables, in the market, the price is a little higher than OM4. And the production of the corresponding optical transceiver like 100G-SWDM4 is still limited. All these restrict the further adoption of OM5 fiber cables.

Summary

It’s getting more costly for fiber optic cabling systems in data centers. As a new MMF type, OM5 offers improved performance over popular OM4 and OM3. With the development of OM5 technology, it will bring more benefits for data centers.

Point-to-Point VS Structured Cabling: Which One Is Best for You?

With the emergence of the Internet of Things, the cloud and mobility, much of the conversation about network connectivity is focused on wireless. However, cabling isn’t going away. Requirements are evolving, but cabling is still an essential component of any IT environment. Because the life-cycle of a cabling system is typically much longer than most of your IT infrastructure, it is important to understand the primary cabling methods and plan carefully. This article will make a comparison between two basic cabling methods: point-to-point cabling and structured cabling.

What Is Point-to-Point Cabling?

Point-to-point cabling refers to a data center cabling system comprised of “jumper” fiber cables that are used to connect one switch, server or storage unit directly to another switch, server or storage unit. A point-to-point cabling system is adequate for a small number of connections. However, as the number of connections in a data center increases, point-to-point cabling lacks the flexibility necessary when making additions, moves or changes to data center infrastructure. When the first data centers were built, end user terminals were connected via point-to-point connections. This was a viable option for small computer rooms with no foreseeable need for growth or reconfiguration. As computing needs increased and new equipment was added, these point-to-point connections resulted in cabling chaos with associated complexity and higher cost. Therefore, there is a downside to point-to-point cabling. However, the point-to-point cabling is surfacing again with the use of top of rack (ToR) and end of row (EoR) equipment mounting options. ToR and EoR equipment placement relies heavily on P2P cables, which can be problematic and costly if viewed as a replacement for standards-based structured cabling systems.

p2p cabling

What Is Structured Cabling?

As it has been mentioned before, point-to-point cabling had aroused many problems. In response, data center standards like TIA-942-A and ISO 24764 recommended a hierarchical structured cabling infrastructure for connecting equipment. Structured cabling is a comprehensive network of cables, equipment and management tools that enables the continuous flow of data, voice, video, security and wireless communications. Instead of point-to-point connections, structured cabling uses distribution areas that provide flexible, standards-based connections between equipment, such as connections from switches to servers, servers to storage devices and switches to switches. Structured cabling is designed to meet Electronic Industry Alliance/Telecommunications Industry Association (EIA/TIA) and American National Standards Institute (ANSI) standards related to design, installation, maintenance, documentation and system expansion. This helps to reduce costs and risk in increasingly complex IT environments.

Comparison Between Point-to-Point and Structured Cabling

Traditionally, point-to-point cabling has been used in the manufacturing sector to establish a direct connection between devices and automation and control systems. However, point-to-point cabling lacks the flexibility, reliability, manageability and performance required for the exploding number of connections within today’s networks.

Structured cabling provides the flexibility that point-to-point does not, as well as the capability to support future technologies, faster connections and more intelligent networks. Although structured cabling has long been the preferred approach in IT, we cannot deny point-to-point cabling completely. Here, the pros and cons of selecting a structured cabling implementation versus point-to-point implementation are listed in the picture below:

Conclusion

Cabling is among the most important considerations for organizations managing a data center, and investing in the right technologies to enable flexibility and optimal performance is key. Although there are several instances where point-to-point Top of Rack or End of Row connections make sense, an overall study that includes total equipment cost, port utilization, maintenance, and power cost over time should be undertaken—involving both facilities and networking—to make the best overall decision. On the whole, point-to-point cabling can present data center many problems. Structured cabling is a better choice over point-to-point cabling.

LC-LC Patch Cable in Data Center

LC-LC patch cable has already become the main force of high density cabling network infrastructure. To future increase the profits of LC-LC fiber patch cable, manufactures has invented LC-LC patch cables of different features to meet various requirements in data center and increase the network performance.

What Kind of Fiber Patch Cable Is Required in Data Center?

Data center is a place of thousands fiber links. The selection of fiber patch cables will directly affect the network performance. More and more data centers choose to select fiber patch cable of high performance. Generally, insertion loss and return loss of connectors terminated on patch cable and light loss of optical fiber used for fiber patch cable are three most basic factors for fiber patch cable selection. To satisfy the increasing demands for higher density and easier management in data center, the optimization of fiber patch cable has never stopped. The following introduces several popular LC-LC fiber patch cables which represent the trends of fiber patch cable that data center is asking for.

LC-LC fiber patch cable

Low Insertion Loss and Bend Loss LC-LC Patch Cable

When a length of fiber patch cable is connected in network, optical light loss occurs at the optical fiber and the connectors terminated on it. There are different optical light losses, among which insertion loss at the connectors and bend loss in fiber optic cables are the two most commonly light losses that technicians are trying to overcome. Manufactures provides LC-LC fiber patch cables which can minimize these losses to the most.

Insertion loss refers to the fiber optic light loss caused when a fiber optic component insert into another one to form the fiber optic link. To provide low insertion loss patch cable, LC connectors terminated on the patch cable has been optimized. Standard LC-LC patch cable usually has an insertion loss less than 0.3 dB. However, for upgraded LC-LC patch cable, the insertion loss is usually lower than 0.2 dB. To decrease the bend loss, a type of bend insensitive fiber (BIF) has been used in fiber patch cable. With optimized LC connectors and bend insensitive fiber, LC-LC fiber patch cable could provide lower light loss during network transmission.

uniboot LC cable

High Density LC-LC Patch Cable

LC connector was invented for higher cabling density. standard duplex LC-LC fiber patch cable can provide much higher cabling density than other duplex fiber patch cables. To further increase cabling density in data center, the connectors and cable diameter of LC-LC patch cable are becoming smaller. Uniboot LC-LC patch cable is a typical example. This kind of fiber patch cable designed the two fibers of the duplex patch cable into a single cable. In adding the two connectors terminated at each end of the duplex patch cable share the same boot. With less using cable counts, uniboot patch cable can provide higher cabling density and better cooling environment in data center.

Polarity Switchable LC-LC Patch Cable

The development of patch cable won’t stop at low loss and high density. Making fiber patch cable easier-to-use is also important. Polarity of fiber patch cable matters a lot during installation of fiber patch cable, especially for duplex fiber patch cable and MTP patch cable. It is common to change the polarity of a duplex patch cable during deployment. Technicians might need tools to change the polarity of patch cable. However, a polarity switchable LC-LC patch cable can make things much easier. Without any tools you can polarity reversal could be really easy. The following picture shows the polarity reversal of a special designed LC-LC patch cable.

polarity switchable LC patch cable

Conclusion

LC-LC patch cable has been designed into many different types. A high performance fiber patch cable should not only provide low insertion loss and bend loss, but also higher cabling density and easy-to-use features. This is also the trend of data center development.

Factors to Consider Before DWDM Network Design

DWDM network deployment usually requires a lot of preparation. There are many factors to be considered before DWDM network design. Even a professional team would take a long time to calculate the parameters over and over to ensure good network performance, let alone some customers who are not experienced. In many cases, customers just have a rough concept of what they need for a DWDM network. When it comes to specific parameters of products, they get no idea. This post offers the most important factors to be considered before DWDM networking. No matter you want to deploy a DWDM network all by your own team, or you want to customize one by other vendors. You will find this post helpful.

DWDM Network Design

What Kind of DWDM Network You Want to Build?

This question contains many details. Here offer several basic factors:

Simplex or Duplex: it is known that DWDM network multiplex different wavelengths together to transmit different ways of optical signals over optical fiber. These wavelengths can be transmitted over the same optical fiber or a pair of optical fibers. Duplex DWDM uses the same for both transmitting and receiving for a way of duplex optical signal over duplex optical fiber. However, the simplex DWDM network uses two different wavelengths for a way of duplex optical signal over a length of single fiber. Thus, the simplex DWDM network provides lower capacity than duplex DWDM network.

Distance: DWDM network gets the greatest returns on investment. It is usually deployed for long distance transmission. But long distance means large light loss. Distance of DWDM network and devices or points it passes should also be considered.

Data Rate and Space Channel: a DWDM network can transmit optical signals of different data rates at the same time. Currently, DWDM network generally transmits 1G and 10G for each wavelength. 1G DWDM SFP, 10G DWDM SFP+ and 10G DWDM XFP modules are usually used. Space Channel of 50 GHz Grid and 100 GHz Grid is commonly applied.

Is There Any Wavelength Adding and Dropping?

The DWDM network needs DWDM MUX/DEMUX for wavelengths multiplexing and de-multiplexing. It is common that a DWDM network passing many places. And wavelengths are required to be added and dropped at some of these places. In this case, DWDM OADM should be used.

DWDM MUX insertion loss test

How to Calculate Light Loss of DWDM Network?

There is light loss in every DWDM network. Technicians should calculate the light loss to decide what devices to be added in the network to ensure good transmission quality. Light loss occurs at many place, the optical fiber for transmission, the DWDM MUX/DEMUX, the devices connected in the network and even the fiber optic splicers and connection points have light loss.

How to Ensure Good DWDM Network Transmission Quality?

There are a variety of factors that can affect the transmission quality. The light source, light loss, transmission distance, fault risks, etc. However, there are always methods to overcome problems. EDFA can be added in the network to ensure enough optical power. If optical power is too strong, fiber optic attenuator can be used. OEO offers conversion between grey wavelengths and DWDM wavelengths. DCM and OLP are separately used for light dispersion compensation and backup line building. These devices can be used properly for good transmission quality.

DWDM MUX

How to Satisfy the Requirements for Both Now and Future?

A DWDM network might only need to transmit several ways of optical signals. However, it might be required to transmission tens of ways optical signals. During the deployment, technician should considerate about the future application. If there is no limit in budget, it would be better to deploy DWDM MUX with more channel port. If not, you can try FS.COM FMU half-U plug-in DWDM MUX modules. You can buy one module for current use and expand the DWDM MUX with another module in the future easily via expansion port on the MUX. All the wavelengths on the DWDM MUX can be customized according to your application.

DWDM long haul

How to Get the Better Performance With Lowest Cost for DWDM Network?

To get the better performance with lowest cost for DWDM network, you need carefully calculate the wavelength, light loss, devices and so on. In practical application, the DWDM network could be really complex, many devices like EDFA, OEO and DCM might be added in the network. It costs a lot for the deployment and management of these devices. Now FS.COM has made these devices into small plug-in cards and offers 1/2/4U chassis to hold them. A free software is also provided for better management and monitoring. This is FS.COM new series of product for DWDM long haul transmission—FMT multi-service transmission platform, which is a cost-effect and high performance system for DWDM network.

Professional Team for DWDM Network Design and Customization

The above mentioned factors are just the basic information that you should consider before DWDM network design. For more professional service and tech support, you can visit FS.COM where you can find professional DWDM network design and customized one-stop solution team and services.