Getting to Know SONET/SDH SFP+ Transceivers

Plesiochronous Digital Hierarchy (PDH) system was the earliest stand used to transport phone calls and data over the same fiber. With the increasing demand of phone calls and data traffic, SONET/SDH are then introduced to replace PDH system to transport the data without synchronization problems. As you can see, SONET/SDH SFP+ transceivers have been widely used in the market. This post will give a brief analysis on SONET/SDH SFP+ transceivers.

SONET/SDH Interfaces Overview

SONET (Synchronous Optical Networking) and SDH (Synchronous Digital Hierarchy) are multiplexing protocols that transfer multiple digital bit streams over optical fiber with lasers or light-emitting diodes (LEDs). SONET and SDH are widely used methods today for very high speed transmission of voice and data signals across the numerous world-wide fiber-optic networks. SONET is the standard used in the United States and Canada, and SDH in the rest of the world. The two are largely equivalent. Although the SONET standards were developed before SDH, it is considered a variation of SDH because of SDH’s greater worldwide market penetration.

We often find SONET/SDH SFP transceiver like Cisco OC-3/STM-1 LR-1 SFP 1310nm 40km IND DOM. What does OC-3/STM-1 mean? OC-3c (Synchronous Transport Signal 3, concatenated) is the basic unit of SONET. Depending on the system, OC-3 is also known as STS-3 (when the signal is carried electrically). STM-1 (Synchronous Transport Module, level 1) is the basic unit of framing in SDH, which operates 155.52 Mbit/s. OC-3c and STM-1 have the same high-level functionality, frame size, and bit-rate.

SONET/SDH and 10 Gigabit Ethernet

10 Gigabit Ethernet (10GbE) means the Ethernet network runs at 10 Gigabit per second. The 10 Gigabit Ethernet defines two PHY (Physical Layer) types: a local area variant (LAN PHY) with a line rate of 10.3125 Gbit/s, and a wide area variant (WAN PHY) with the same line rate as OC-192/STM-64 (9,953,280 Kbit/s).

10GbE provided the potential for an Ethernet solution aligned with the data rate of OC-192 backbone. It’s the first time in Ethernet history that no additional speed matching equipment would be required to link with the WAN. A seamless end-to-end Ethernet network can be built with less money. But the question is how to balance the compatibility with the installed base of OC-192 equipment while still meeting the economic feasibility criteria of the P802.3ae Task Force in defining the 10GE WAN PHY. To solve this problem, an OC-192 frame format is provided to support only the SONET overhead features required for fault isolation. This simplification avoids unnecessary functions and cost.

In order to make sure that WAN PHY optics would benefit from the high volumes and low cost of Ethernet, the serial 1310 nm and 1550 nm transceiver modules were kept the same as the LAN PHY. Since the 1310 nm and 1550 nm transceiver modules are designed for up to 10km and 40 km links respectively, they will inter-operate with OC-192 transceiver modules for 1310 nm and 1550 nm over intermediate reach, respectively.

FS.COM SONET/SDH SFP+

FS.COM supplies OC-192/STM-64 SFP+ for short reach (SR-1, VSR) , intermediate reach (IR-2) and long reach (LR-2) applications. These SFP+ modules are compatible with the SONET/SDH and ATM standards. For more details, please visit the website at fs.com.

GBIC or SFP — Which One Is Your Choice?

As is known to all, fiber optical transceivers are developed along the way to achieve more compact sizes, such as GBIC, SFP, SFP+ and so on. Meanwhile, these transceiver modules are available with a variety of transmitter and receiver types, allowing users to select the appropriate transceiver for each link to provide the required optical reach over the available optical fiber type (e.g. multi-mode fiber or single-mode fiber). In addition, there are a variety of interface types of GBICs and SFPs, like 1000Base-SX, 1000Base-LX/LH, 1000Base-EX or 1000Base-T etc. Faced with so many choices, some people are confused when choosing the proper one for their project.

Recently many users ask when they choosing a card for their switch/router, they should choose either cards that take SFP or cards that take GBIC. It seems to be a headache for them because they are not clearly know the differences of them. The following will tell you when it’s best to use GBIC or SFP.

GBIC (gigabit interface converter)

GBIC is a hot-swappable input/output device that plugs into a Gigabit Ethernet port or slot, linking the port with the network. GBIC is a standard for transceivers, commonly used with Gigabit Ethernet and fiber channel. GBIC module is hot pluggable, this feature allows a suitably designed enclosure to be changed from one type of external interface to another simply by plugging in a GBIC having the alternative external interface. Generally, GBIC is with the SC connector. The GBIC standard is non-proprietary and is defined by the Small Form Factor committee in document number 8053i. The first publication of the proposal was in November, 1995. A few corrections and additions were made in September, 2000.

SFP (small form-factor pluggable)

SFP is a specification for a new generation of optical modular transceivers. The form factor and electrical interface are specified by a multi-source agreement (MSA). SFP is also known as a Mini GBIC as its function is somewhat similar to the GBIC transceiver while SFP is smaller than it. SFP transceivers are designed to support SONET, gigabit Ethernet, Fibre Channel, and other communications standards. Due to its smaller size, SFP is now more and more widely used for both telecommunication and data communications applications.

GBIC & SFP Interface Types

For every type of GBIC and SFP transceivers, it works with different wavelengths at a designated location or distance. For examples, SX SFP uses 850nm for a maximum of 550 meters, LX SFP uses 1310nm for a maximum 10km, ZX SFP could reach 80km or copper SFP uses a RJ45 interface. We can easily distinguish via the information in their names or models, ie. 1000BASE-T, 1000BASE-SX, 1000BASE-LX/LH, 1000BASE-ZX, 1000BASE-CWDM, or 1000BASE-DWDM. In addition, the DOM function for an SFP is discretionary. It supports the users to locate the real-time working status of SFP. The famous brand of GBICs or SFPs are Cisco, Finisar, HP, Juniper, Extreme Network and so on. There is a little difference in the features of each brand’s GBICs and SFPs and they support their corresponding brand’s switches/routers.

When it’s best to use GBIC and When to use SFP?

According to the above definitions of GBIC and SFP, you may have a further understanding on both of them. There is only one difference of them. SFP is smaller than GBIC. Because the smaller size of SFP (almost half the volume of GBIC), we can configure double number of ports on the same panel which increases the utilization rates of switches/routers. Other basic functions of SFP is almost the same with the GBIC and they are equal in performance. Though there are some users still using the GBIC as their old divice which can not be updated to support SFP, GBIC will gradually be obsoleted and replaced by SFP. So the answer to the question “When it’s best to use GBIC and When to use SFP?” is very noticeable.

The Basics of 1000BASE-LX SFP Transceivers

In telecommunication networks, Gigabit Ethernet is a term describing various technologies for transmitting Ethernet frames at a rate of a gigabit per second, as defined by the IEEE 802.3-2008 standard. As a type of wiring for Gigabit Ethernet, you may see 1000BASE-LX on an SFP transceiver, what does 1000BASE-LX mean? And what can 1000BASE-LX SFP transceiver achieve? This passage will give you the answer.

What Is 1000BASE-LX?

1000BASE-LX, a type of standard for implementing Gigabit Ethernet networks, is specified in IEEE 802.3 Clause 38. The "LX" in 1000BASE-LX stands for long wavelength, indicating that this version of Gigabit Ethernet is intended for use with long-wavelength transmissions over long cable runs of fiber optic cabling. 1000BASE-LX uses a long wavelength laser (1270–1355 nm), and a maximum RMS (root mean square) spectral width of 4 nm. The letter "X" indicates that 8B/10B signal encoding technique is used.

How 1000BASE-LX Works?

1000BASE-LX can run over both single mode fiber and multi-mode fiber. 1000BASE-LX is specified to work over a distance of up to 5 km over 10 µm single-mode fiber. 1000BASE-LX uses 1300 or 1310nm single mode fiber and laser. Its specification says the maximum operation length is 5km. But manufacturers often guarantee over 10km working length. 1000BASE-LX can also run over all common types of multi-mode fiber. The modal bandwidth for the MMF options ranges from 400 MHz/km to 500 MHz/km, and maximum distance is 550 meters. For link distances greater than 300 m, the use of a special launch conditioning patch cord may be required. This launches the laser at a precise offset from the center of the fiber which causes it to spread across the diameter of the fiber core, reducing the effect known as differential mode delay which occurs when the laser couples onto only a small number of available modes in multi-mode fiber. 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 multi-mode building fiber backbones and single mode campus backbones. Careful notice should be given to the range of differences, both in distance and price of multi-mode and single-mode fiber optics.

1000BASE-LX SFP Transceivers

1000BASE-LX is the long wavelength implementation of a similar transceiver that can obviously span a further distance. 1000BASE-SX SFP transceiver module is compatible with the IEEE 802.3z standard and can use both 62.5 and 50 micron multi-mode fiber, as well as single-mode fiber optic cables, with distances of 440m, 550m and 5km respectively. 1000BASE-LX SFP transceivers are available with a variety of transmitter and receiver types, allowing users to select the appropriate one for each link to provide the required optical reach, depending on the customer application and distance capability required. Each optical interface operates and is managed like a fixed port but gives the customer flexibility to hot-swap or interchange to different optical module types.

FS.COM offers a wide range of 1000BASE-LX SFP transceivers branded by many famous companies, like Cisco, Juniper, and HP. Besides, they also provide other types of 1000BASE SFP transceivers, such as 1000BASE-LH SFP (eg. Cisco GLC-LH-SMD), 1000BASE-LX SFP, 1000BASE-ZX SFP, 1000BASE-SX SFP (eg. HP J4858C) and so on.

Introduction to BiDi Optical Transceivers

In the past few decades, a new class of pluggable optical transceivers have been developed that send and receive optical signals end-to-end over a single fiber strand. This reduces by half the amount of fiber required for that same total data transmission. This factor-of-two improvement can lead to substantial cost savings especially in campus environments with large numbers of connectivity endpoints.

Bi-Directional transceivers, called BiDi’s for short, use two different wavelengths to achieve transmission in both directions on just one fiber. The modules are deployed in pairs, one for the upstream (“U”) direction and another for the downstream (“D”). The standard defining these parts is the IEEE 802.3ah Gigabit Ethernet 1000BASE-BXnn (nn= transmission reach in kilometers) specification for point-to-point Ethernet in the First Mile (EFM) applications.

The value of the BiDi solution derives from the reduction in the use of fibers by a factor of two. There are many situations in real-world networks where this reduction is extremely important if not absolutely required. As mentioned above, the IEEE802.3ah specification defining BiDi’s mentions point-to-point Ethernet in the First Mile (EFM) applications. In addition, BiDi transceivers can be of great use in any situation where only limited fibers or limited conduit space is available. Other common applications include: digital video and Closed Circuit TeleVision (CCTV) applications and high-density switch-to-switch port interconnection.

BiDi Technology…how they work…

As mentioned above BiDi transceivers are deployed in matched pairs, one for the upstream (“U”) direction and another for the downstream (“D”), each part transmitting at a different wavelength. The figure below depicts the details of such a matched set of BiDi transceivers. In this example, the two wavelengths utilized by the BiDi pair are 1310nm and 1490nm. Typically the “Upstream” or “U” transceiver transmits at the shorter of the two wavelengths and the “Downstream” or “D” module the longer wavelength.

The key additional technology present in BiDi’s that is not present in standard 2-fiber transceivers is the “Diplexer”. The Diplexer acts simultaneously couples the locally transmitted wavelength onto the single fiber while “splitting” off the received wavelength so it is directed at the receiver.

Economic Case for BiDi’s

The value of the BiDi solution derives from the reduction in the use of fibers by a factor of two. There are many situations in real-world networks where this reduction is extremely important if not absolutely required. As mentioned above, the IEEE802.3ah specification defining BiDi’s mentions point-to-point Ethernet in the First Mile (EFM) applications. In addition, BiDi transceivers can be of great use in any situation where only limited fibers or limited conduit space is available. Other common applications include: digital video and Closed Circuit TeleVision (CCTV) applications and high-density switch-to-switch port interconnection.

The simplest economic case for BiDi’s is probably a campus environment requiring fiber connectivity to a large number of endpoints. For example, most universities campuses are spread over a fairly wide area and required high-speed (read: fiber) connectivity between campus core resources (e.g., databases, computing resources, common internet access, etc.) and a large number of classrooms, dorm rooms, and faculty and administrative offices. The following is a simple economic model to demonstrate the savings possible in such an environment using BiDi versus standard 2-fiber transceivers.

So, for a campus environment where average link length is greater than 800 feet, the BiDi solution is the right decision. In an real world example, a large university campus lighting 400 GbE fiber links with an average length of 1600 feet used BiDi’s to save $32,000 versus using 2-fiber transceivers.

FS.COM BiDi Offering

FS.COM offers BiDi transceivers in the SFP form-factor supporting 1GbE for all major switch brands like Cisco, HP, Juniper, Extreme, Brocade, etc. We offer a 1Gbps SFP BiDi’s to cover a wide range of distances including: 10km, 20km, 40km, 80km and 120km, all of which are ROHS compliant. To aid in turn-up and maintenance of BiDi links, all FS.COM BiDi transceivers support Digital Diagnostics Monitoring (DDM as defined in standard SFF-8472) allowing real-time monitoring of parameters of the fiber SFP, such as optical output power, optical input power, temperature, laser bias current, and transceiver supply voltage.

3 Reasons Why You Should Use HP JD119B Compatible SFPs

As more and more companies are moving towards fiber optic networking, one question we often hear is "Will we be able to use our existing equipment with the new wiring?" In most cases, the answer to this is yes! If you're using HP networking equipment with SFP/SFP+ interfaces, you can simply buy some plug-and-play transceivers which change the network connectors to match your new fiber runs as long as the transceivers are compatible with the originally branded devices.

One common issue when using optical transceiver is that many vendors charge too much for their transceivers, assuming companies will simply pay without doing their homework. But if you're looking for 1000BASE-LX transceivers for your HP hardware, you can turn to FS.COM for their own brand of fully HP-compatible transceivers and get a lot more value with a lot less money.

Three Reasons To Turn To FS.COM For Your HP JD119B SFPs

1. 100% Compatibility

One thing a lot of people haven’t realized about optical networking equipment is that there are only a handful of factories in the world which are certified to produce it. Every store that sells top-grade SFP transceivers is getting them from the same few vendors. And FS.COM uses them too.

FS.COM HP compatible JD119B 1000Base-LX transceivers are fully MSA-compliant, so they adhere to all relevant standards for optical equipment. They also come pre-loaded with the compatible coding on the EPROM chip so that your HP hardware will recognize it as soon as it's plugged in. Not only the 1000Base-LX transceivers, all the other compatible transceivers from FS.COM are the same. For example, if you plug a Juniper Networks EX-SFP-10GE-LR compatible 10GBASE-LR SFP+ into the Juniper Networks switches, the switches will report them as "official" when checking the transceiver status.

2. Excellent Support

With most name-brand SFP transceivers, you get a minimal warranty. Usually it's a year at most, and often as low as 90 days. Despite how much you pay for transceivers from the major vendors, they simply don't offer much support to go with it.

But in FS.COM, you can get fully guarantees for their HP compatible SFPs. You get a true lifetime warranty, with parts replacement if needed, as well as unlimited technical assistance if you need any help. This greatly enhances the value of a product that's already a great value, and ensures your transceivers continue to function properly for the life of your network.

3. Prompt Shipment

Unlike many other vendors, FS.COM keeps a wide stock of our transceivers in-house and ready to ship. For hot products, we could deliver the same day while the market needs one week, and when the market needs two or three weeks, we only take one week, and the market one or two months, we half the month. In many cases, we can ship them to you same day.

Even if you're not looking to buy transceivers today, just keep that in mind. If there's ever an emergency, or a mistake when ordering new hardware, just contact us and we'll get you the transceivers you need as soon as possible.

But The Best Reason Is Huge Savings

Although the prices are very high for HP's own JD119B transceivers, they truly do not cost much to produce. They're priced according to the razor blade model, assuming that people with HP hardware are going to naturally buy HP SFPs as well. While FS.COM own HP compatible transceivers cost roughly one-tenth of the MSRP of HP's official transceivers. Even on sale from discount outlets, you'll still pay far more for the official version, but you won't actually get a better product, and you'll definitely get a worse warranty.

Whether you need HP compatible transceivers or any other brand-compatible transceivers, FS.COM can fulfill your requirements rapidly. As a vendor you can trust, FS.COM offers a wide range of transceivers suited for varied applications. Each of the optics is tested to ensure the 100% compatibility with major brands like Cisco, HP, Juniper, Nortel, Force10, D-link, 3Com, etc.