Copper & Optical SFP Modules

srijeda , 25.05.2016.

In order to maintain the configuration flexibility and establish connections that allow smooth data transfer from the source to the end point, SFP transceiver modules are utilized in the copper or optical Gigabit Ethernet (GbE) networks. SFP (Small Form-factor Pluggable) is a compact, hot-swappable, input/output device used in data communication and telecommunications networks. SFP interfaces between communication devices like switches, routers and fiber optic cables, performing optical and electrical signal conversion. There are many copper an optical SFP transceivers based on different GbE physical layers, such as Cisco 1000BASE-T SFP-GE-T and 1000BASE-SX SFP MGBSX1.

GbE Development
The initial standard for GbE was produced by the IEEE in June 1998 as IEEE 802.3z. Two designs were ratified in IEEE 802.3z to transmit signals over optical cables: the 1000BASE-SX uses short-wavelength laser (850nm) on multi-mode fiber (MMF), and the 1000BASE-LX uses long-wavelength laser (1310nm) on the standard single-mode fiber (SMF). At that time, transmitting 1000Mbps signals on the widely deployed Category 5 UTP was a significant challenge for silicon-chip designers. It requires tremendous signal processing to mitigate the channel impairments in copper wires such as ISI (intersymbol interference) introduced by limited channel bandwidth and signal crosstalks between pairs of copper wires. It was not until a year later that the 1000BASE-T standard (IEEE 802.3ab) was finished. To keep the cost of GbE low, the IEEE 802.3z committee very conservatively defined the transmission distance limit of 1000BASE-SX as 300m, and that of 1000BASE-LX as 5 km.

SFP Port Types
Specified by the Multisource Agreement (MSA), SFP, also known as a mini gigabit interface converter (GBIC), delivers the similar functions just as what a GBIC does, but designed with a much smaller size. As mentioned above, SFP transceiver has several interfaces which are standardized to work on SMFs and MMFs. Besides, SFP transceivers are also available with copper cable interfaces, like 1000BASE-T. This means that SFP module which is designed primarily for optical fiber communications can also communicate over unshielded twisted pair (UTP) cables. The image below shows different GbE SFP standards.

Copper SFP Modules
The development of copper technology in SFP modules is of great importance in enabling system designers to meet objectives while simplifying their inventory and reducing operating costs. These copper SFP transceivers scale Ethernet 10/100Mbps performance to 1000Mbps. Compared with 1Gbps, 1000BASE-T is 100 times as fast as the standard Ethernet. Additionally, the Full Duplex Repeaters (FDRs), when coupled with 1000BASE-T, offer an easy-to-manage, high-burst rate, and shared-media solution capable of supporting both end users and server farms. Popular copper SFP products, like Cisco SFP-GE-T, are used in Gigabit networks and they are fully compatible with 1000Base-T.


Optical SFP Modules
Both 1000BASE-SX and 1000BASE-LX are standardized for fiber optics. They share the 8B/10B 1000BASE-X PCS line coding. In addition to the transmission media, the only difference between 1000BASE-SX and 1000BASE-LX lies in the physical medium dependent (PMD) layer which defines the laser transmitter and photodetector. The interface between the physical medium attachment (PMA) and PMD layer is simply a serial interface. This made it easy to reuse all the designs between 1000BSAE-SX and 1000BASE-LX except the PMD transceiver.


Modern optical SFP modules support digital diagnostics monitoring (DDM) functions, also known as digital optical monitoring (DOM). This feature gives users the ability to monitor the real-time parameters of SFP, such as optical output power, optical input power, temperature, laser-bias current and transceiver supply voltage. The real-time diagnostic parameters can be monitored to alert the system when the transceiver’s specified operating limits are exceeded and compliance cannot be ensured. What’s more, the DDM function can be used to isolate the particular location of fault in fiber optic network system. Combining the DDM interface status flags, transceiver hard pins and diagnostic parametric monitor data the specific location and cause of a link failure can be pinpointed. Certainly, DDM function also has its role in failure prediction on fiber optic links, which is based on the transceiver parametric performance., including device faults and high error rate conditions.

SFP Module Applications
Apart from GbE, SFP modules can also support other communications standards, including synchronous optical networking (SONET)/synchronous digital hierarchy (SDH), and fiber channel. They allow the transport of fast Ethernet and GbE LAN packets over time-division-multiplexing-based WANs, as well as the transmission of E1/T1 streams over packet-switched networks.

SFP Purchasing Tips
When picking such a SFP module for your network, the first important factor to be considered is the price, especially for those small and medium-sized enterprises who have a tight budget. The other points go to the product compatibility, stability, and reliability. Otherwise, no matter how low the price is, it’s of no use.

Conclusion
Copper and optical SFP modules have proven themselves as the useful devices for the increased bandwidth requirements of users with each passing day. Fiberstore supplies a wide range of SFPs to support both copper and optical interfaces. They are fully compatible with such famous brands as Cisco, Juniper, D-Link (ie. DEM-311GT). Here just lists a few for your reference. For more information about SFP modules, you can visit Fiberstore directly.

Oznake: GbE, SFP, 1000BASE-T, SFP-GE-T, 1000BASE-SX, MGBSX1, DEM-311GT, 1000BASE-LX

Transceiver Selection Guide for Your Networking Use

četvrtak , 24.03.2016.

Thanks to the advances made in fiber optical technologies, fiber solutions have been deployed in ever-increasing applications where high-speed and high-performance data transmission is needed. They outweigh the copper solutions in such aspects as higher bandwidth, longer distances and Electromagnetic interference (EMI) immunity. Transceivers, one of the key components required in such fiber connections for high networking performance, have experienced the never-ceasing industrial designs, from lower port density to higher, from the standard modules to the final hot-pluggable ones, to meet the ever more flexible networking infrastructure.

There is a broad selection of hot-pluggable transceiver modules available for fiber networking use, and you may feel a little confused about how to select the correct transceivers for your networking transmission. In this article, I will illustrate different aspects of transceivers that need to be known before choosing a transceiver.

Transceiver Basics
Before giving guidance to transceiver selection, it’s necessary to know the basics of transceiver. Transceiver is a combination of a transmitter and a receiver in a single package, while they function independently for bidirectional communication. Typically, a fiber optic transceiver converts the incoming optical signal to electrical and the outgoing electrical signal to optical. More specifically, the transmitter takes an electrical input and converts it to an optical output from a laser diode or LED. The light from the transmitter is coupled into the fiber with a connector and is transmitted through the fiber optic cable plant. The light from the end of the fiber is coupled to a receiver where a detector converts the light into an electrical signal which is then conditioned properly for use by the receiving equipment.

Here go the several aspects of transceivers that are helpful in your purchasing.

Form-factor
Multi-source agreements (MSAs) between different equipment vendors specify guidelines for electrical and optical interfaces, mechanical dimensions and electro-magnetic specification of a transceiver. The equipment vendors follow these MSA defined values for designing their systems to ensure interoperability between interface modules. The form-factor or the MSA-type is needed so that the transceiver can mechanically and electrically fit into a given switch, router, etc. Transceiver MSAs define mechanical form factors including electric interface as well as power consumption and cable connector types. There are various MSA types: SFP (eg. MGBSX1), SFP+, XFP, CFP, CFP2, CFP4, QSFP and so on.

Transmission Media
Transceivers can work over single-mode fiber (SMF), multi-mode fiber (MMF), and copper. In different Ethernet applications, media can achieve different link lengths when combined with transceivers. Take Gigabit Ethernet (GbE) applications for example, single-mode transceivers can have a transmission distance of 5km to 120km, while multi-mode transceivers are defined to have the maximum reach of 55om, with copper solution establishing even fewer link length at 25m. Take MGBLX1 for example, this Cisco compatible 1000BASE-LX SFP works through SMF for 10km reach.


Power Budget
The transceiver power budget is the difference between transmitter launch power and receiver sensitivity and has to be 2-3dB larger (Margin) than the measured link loss. If the link loss cannot be measured, it has to be calculated. Therefore transmission distance [km], the number of ODFs, patches and passive optical components (Muxes) have to be known. Common values for power budget are <10, 14, 20, 24, 28, >30dB.


If you’re seeking high-speed data carrier, transceivers can help accomplish goals. By transmitting data at 10Gbit/s, 40Gbit/s, 100Gbit/s or 12940Gbit/s, they can ensure that data arrives quickly. Transceiver modules that are capable of handling fast speeds can help with downloads and high and low bandwidth video transmission.

Conclusion
Transceivers are instrumental in ensuring that the data is transmitted securely, expeditiously, and accurately across the media. Choosing the right type of transceiver for your network is not always easy, but knowing above discussed parameters beforehand helps you narrow it down to a few transceivers. Fiberstore offers a sea of transceiver modules which are fully compatible with major brands, like the above mentioned MGBSX1 and MGBLX1, the Cisco compatible transceiver modules. For more information about transceiver modules, you can visit Fiberstore.

Oznake: transceivers, MSAs, SFP, MGBSX1, compatible transceiver modules, MGBLX1