ABC of GPON SFP: Understanding GPON OLT / ONU / ONT SFP Module

Since the advances in Ethernet technology, “last mile” connectivity is expected to realize between the network backbone and local area networks (end users). Gigabit Passive Optical Network (GPON) is a cost-effective point-to-multipoint access network, which brings great improvement in data transmission distance (up to 20km) and bandwidth (an downstream capacity of 2.5Gbit/s and an upstream capacity of 1.25Gbit/s ). However, GPON’s higher bandwidth and split ratios are only achievable by using GPON-capable optical transceivers. It is well positioned to help meet the needs for higher bandwidth in FTTx applications, and continues to fuel growth in demand for GPON SFP modules. So this article will introduce the basics of GPON SFP, including GPON OLT, GPON ONU and GPON ONT SFP module.

gpon-network

What Is GPON SFP Module?

GPON SFP is a new higher-speed bi-directional optical transceiver, which can deliver 2.5 Gbits/sec of bandwidth. And it is a kind of single fiber transceiver which comes with SC connector and can transmit data up to 20km. In addition, it features a 28-dB optical loss budget to enable 1:64 split ratios and provides adequate optical loop lengths. Most EPON and some BPON systems deployed today use 25-dB optics, which limit the split ratio and loop length. For this reason, GPON transceiver enjoys the added advantage of industrial demand. The key performance advantage is to reduce the upstream split loss arising from utilizing the mode-coupled-receivers (MCR) in a PON application. Moreover, this innovative module dose not outweigh the costs over a standard module. For these two reasons, the GPON SFP modules are very attractive to the network operators to improve the utilization of GPON network. On top of that, GPON SFP transceiver is an essential part of GPON system which is necessary both for optical network unit (ONU) installed at the subscriber’s premises and for the optical line terminal (OLT) at the central office (CO). The following part will respectively introduce the GPON OLT, GPON ONU and GPON ONT SFP module.

GPON SFP

GPON OLT SFP Module

GPON OLT SFP is designed for OLT side in GPON network. OLT is a equipment integrating L2/L3 switch function, which is located in central office (CO). The main function is to control the information float in both directions: upstream and downstream. The GPON OLT module plays an inevitable role in the upstream and downstream transmission. In order to put across the transmission process, the downstream transmission is taken as an example. A single mode optical fiber coming from OLT (at the central office) PON port, runs to the passive optical splitter (POS) located near end users. And then the optical splitter will divide signals into separate paths which can provide service up to 64 end users. In this basic GPON topology, a GPON OLT module is used to connect a single-mode fiber patch cable to a passive optical splitter. Therefore, GPON OLT transceiver works to get the data, voice and video traffic from metro network or from a long-haul network.

GPON OLT SFP Module Application

GPON ONU/ONT SFP Module

Since the ONU and ONT are deployed at customer’s premises, they are connected to the OLT by means of optical fiber and no active elements are present in the link. In GPON network, the ONU/ONT transceiver is the physical connection between the customer premises and the central office OLT. This type of modules gets the signals from OLT, so they have the opposite characteristic of GPON OLT transceiver, incorporating a high performance 1310nm burst mode DFB transmitter and 1490nm CW mode APD receiver. By being plugged into advanced “triple play” (data, voice & video) ONT or ONU equipment (with SFP ports), such as Ethernet switches, routers, DSLAMs or home gateway, ONU/ONT SFP module fits seamlessly into existing communications equipment and provides end users with a smooth upgrade to GPON. Therefore, GPON ONU/ONT SFP module plays an important role in the applications for point-to-multipoint (P2MP) ONT / ONU equipment in GPON network.

GPON ONU ONT SFP Module Application

Conclusion

GPON SFP transceiver meets the the requirements of FTTx network to accelerate the speed or capacity. GPON OLT, ONU and ONT SFP module have their respective roles to play in the GPON networks. Many people may worry the high attenuation losses from optical splitter in the GPON networks, as above mentioned, the GPON optical module is just used to solve this problem in that it utilizes the MCR technology that protects large numbers of signals. In a word, this new module is a compelling network alternative to save cost and increase bandwidth and security.

Related Article: ABC of PON: Understanding OLT, ONU, ONT and ODN

Copper SFP vs Optical SFP: Which One Is the Best to Use?

The war of copper vs fiber has raged for years. Fiber seems to operate as a rival to copper rather than a replacement until now, it has already established a niche in the industry. However, with recent advances in copper technology, the copper presents the same step-ladder upgrade path. The speed difference between the two media is considerably smaller. In some ways, the copper matters most to IT experts and data center decision makers. But many end-user organizations still face tough decision about which type is the best overall value for their current and future projected needs. This battle is also being waged in SFP transceivers, there is a measurable difference in the copper SFP vs optical SFP. This article will explore their respective strengths and weaknesses and reveal insights into how IT experts are to proceed.

Copper SFP vs Optical SFP banner

Copper SFP vs Optical SFP: Copper SFP Is a Balanced Choice in Environment Restrictions

The Gigabit RJ45 copper SFP transceiver supports 1000Mbps over Cat5 cables with RJ45 connector interface, which operates on standard Cat5 unshielded twisted-pair copper cabling of link lengths up to 100 m (328 ft). GLC-T is a typical Cisco 1000BASE-T SFP copper RJ-45 transceiver. For short-distance links on a Gigabit switch, it makes no difference if you use SFP ports or RJ45 ports to interconnect switches. Copper SFP is popular to be used for short range uplinks, as it’s easier and cheaper to use 1G copper SFPs and patch cables. And SFP ports are primarily for allowing fiber connections over longer distances. Especially in some case, Copper SFP will make sense if the switch on one side does not have copper ports but SFP slots and the switch on the other side only has copper and can’t be fitted with fiber ports. Or if you don’t need the distance of fiber, you can consider converting SFP to RJ45, which will depend on the switch to determine what copper speeds (10/100/1000) are supported on a copper SFP. Moreover, using copper SFPs to connect the regular copper Gigabit ports is a wise choice to make the best use of the corresponding number of SFPs on existing connected switches.

Copper SFP

Copper SFP vs Optical SFP: Fiber SFP Is More Flexible in Long Distance

The optical fiber SFP modules with LC or SC optical connectors are available in Fast Ethernet and Gigabit Ethernet. And these SFP modules are industrially rated to perform in the most difficult operating environments. The SFP fiber module offers different wavelengths and optical power budget to allow distances from 550m to 120km. A variety of 1Gbps SFP modules in different distance can be found in FS.COM. Some statics also shows that the legacy SFP can hit 4.25Gb/s at 150m, or up to 1.25Gb/s for 160km runs and a variety of ranges/speeds in between depending on type of fibre. Generally, when the distance of the run is over 328 ft/100 m, fiber SFP module must be considered instead of copper SFP RJ45 module, since 1000Mbps could only go as far as 100m over copper cabling. In that sense, optical fiber SFP offers the substantial advantage over copper SFP.

Fiber SFP

Copper SFP vs Optical SFP

  • Operating Temperature

For the standard fiber SFP and copper SFP, there is no difference for the operating temperature – they support 0 to 70°C (32 to 158°F) case temperature as default. In fact, there is more heat dissipated for optical or electrical transmission in the specific applications. Generally, the copper SFPs run much hotter than the fiber SFPs. There are two factors that affect the temperature: power consumption and the case surface. The typical power consumption of fiber SFPs is 0.8W, the copper SFP is 1.05w, that’s why copper SFP have a higher case temperature. In the same environment, the fiber SFP runs at 40°C (104°F) while the copper SFP should run around 52°C (126°F).

  • Distance

As mentioned above, copper SFP supports the max cable distance is 100m, so it is commonly used to interconnect between switches and servers in horizontal and shorter-length backbone applications. While the fiber SFP allows the transmission distance up to 120km, which demonstrate the high performance over longer distances.

  • Security

When security could be considered as a problem in the connection, using fiber SFP module is better than RJ45 copper SFP module. Because fiber doesn’t conduct electricity that makes it resistant to lightning strikes.

  • Cost

Copper SFP transceiver might be more expensive than fiber SFP module in the same short distance. In Gigabit Ethernet applications, when copper SFP is used in combination with cooper cables in short runs, it is more cost effective as the copper cables are more cheaper than fiber cables. Besides, with the boom of third-party vendors, their full-compatible and trustworthy fiber SFP modules are developed to support lower cost fiber runs. The price gap between 100m copper transceiver and 40km 1000BASE-EX SFP fiber transceiver is reduced. More choices are provided for customers to meet their specific demands.

FS P/N Description FS.COM Price
SFP-GB-GE-T Cisco GLC-T Compatible 1000BASE-T SFP Copper RJ-45 100m Transceiver $ 21.00
SFP1G-SX-85 Generic Compatible 1000BASE-SX SFP 850nm 550m DOM Transceiver $ 6.00
SFP1G-EX-55 Cisco GLC-EX-SM1550-40 Compatible 1000BASE-EX SFP 1550nm 40km DOM Transceiver $ 24.00

Conclusion

Through copper SFP vs optical SFP, we can see that each technology has its own set of advantages and disadvantages. Optical fibre SFP is not necessarily better than copper SFP. In fact, mixing copper and fiber solutions is the best practice for data center, as a versatile solution is critical to ensuring the data center remains both manageable and scalable when performance demands skyrocket. Network industry is unpredictable, and the demands of tomorrow may require facilities to investigate solutions they may have scoffed at a year ago.

Related Article: A Quick Overview of Cisco 1000BASE-T GLC-T SFP Copper Module

Choose 10GBASE-T Copper Over SFP+ for 10G Ethernet

24-Port Switch Selection: Which Is the Suitable Choice?

An Ethernet switch acts as a bridge to connect different parts of a network together. Although many routers also possess the network switching capabilities and multiple Ethernet ports, the Ethernet switch is not the replacement for routers. It is worth emphasizing that Ethernet switches are smarter than routers in that they operate at the data link layer (Layer 2) and the network layer (Layer 3) of the OSI Reference Model and therefore support any packet protocol. Ideally, switches will make better use of bandwidth if you prefer wired to wireless connections but have more devices than available Ethernet ports. On the other hand, an Ethernet switch is a costly way to expend the network in home or small business. So it is very important to invest an Ethernet switch with the appropriate number of ports to fit your needs. In the midst of various Gigabit Ethernet switches, a 24-port switch is considered as the most common Gigabit switch that connect devices in a local area network. Then this article will explore how to select a suitable 24-port switch.

Popular 24-Port Switch in the Market

FS S3800-24F4S 24-Port Switch

FS S3800-24F4S 24-port switch comes with 20x 100/1000BASE SFP, 4x 1GE combo and 4x 10GE SFP+ slots. The flexible port combination form provide a high bandwidth aggregation connectivity for multiple switch in network to enhance network capacity. Moreover, it is a stackable SFP managed switch, which can provide true stacking of up to 4 switches in a stack acting as a single unit with totally 106 ports (96x 1G Ports and 10x 10G ports). The switching capacity is 128Gbps. This 24-port Gigabit managed switch fits for enterprise network operators who need high performance and low power processor to provide full speed forwarding and line-dormant capacity.

FS S3800-24F4S 24-Port Switch

Figure 1: FS S3800-24F4S 24-Port Gigabit Switch

Cisco SGE2000 24-Port Switch

Cisco SGE2000P comes with 24 10/100/1000BASE-T RJ45 ports and 4 shared Gigabit SFP slots. This 24-port Gigabit managed switch can provide ACL (access control lists), DoS (denial-of-service), VLAN and IEEE 802.1X port authentication. And the enhanced quality of service (QoS) and traffic-management features help ensure clear and reliable voice and video communications. This Gigabit network switch enable you to take advantage of the comprehensive feature set for a better-optimized, more secure network.

Cisco SGE2000 24-Port Gigabit Switch

Figure 2: Cisco SGE2000 24-Port Gigabit Switch (Source: Cisco)

NETGEAR ProSAFE GS724T 24-Port Gigabit Switch

The Netgear ProSafe GS724T is armed with 24 copper 10/100/1000 ports and 2 SFP 100/1000 ports. Each port can transfer data at maximum throughput for a total maximum switching speed of up to 48 Gbps. This 24-port switch is intended for SMB organizations using the switch for applications like VoIP, video conferencing, and system security, etc. And it features a fanless system, allowing the switch to work silently without overheating. This is great for use on homelab, as its quiet operation won’t cause a distraction.

NETGEAR ProSAFE GS724T 24-Port Gigabit Switch

Figure 3: NETGEAR ProSAFE GS724T 24-Port Gigabit Switch (Source: NETGEAR)

TP-Link TL-SG1024 24-Port Switch

The TP-Link TL-SG1024 features 24 Gigabit Ethernet ports and non-blocking switching, which can provide large file transferring and also be compatible with 10Mbps and 100Mbps Ethernet devices. Moreover, this network switch has 48Gbps switching capacity with 8K MAC address table, 10KB Jumbo Frame and 4MB buffer memory. This TP-Link switch is a fanless rack mount design with LED diagnostic lights, so you can easily tell which ports are in use. It can automatically adjust power consumption according to the link status to limit the carbon footprint of your network. The price is $69.99 on Amazon. So this fanless Ethernet switch is good for your wallet both because it is inexpensive to buy and because of its energy-saving technology.

TP-Link TL-SG1024 24-Port Gigabit Switch

Figure 4: TP-Link TL-SG1024 24-Port Gigabit Switch(Source: TP-Link)

Comparison of 24-Port Switch

Gigabit Switch Mode Ethernet ports Gigabit SFP SFP+ Uplink ports Switching Capacity Forwarding Rate Power Consumption Price
FS S3800-24F4S 24 4 combo 4 128Gbps 95Mpps ≤60W(Full-loaded) $449
Cisco SGE2000 24 4 / 48Gbps 35.7Mpps 90W $390
NETGEAR ProSAFE GS724T 24 2 / 48Gbps No Information 29W $219.99
TP-Link TL-SG1024 24 / / 48Gbps 35.7Mpps 13.1W $69.99

From the chart we can see, all the Gigabit switches listed above provide 24 port Ethernet RJ45 ports, only FS S3800-24F4S 24-port switch has 4 SFP+ uplink ports. They have some characteristics in common that make them suitable for being used in places like home or small business office. In terms of the power consumption, TP-Link TL-SG1024 and NETGEAR ProSafe GS724T are lower than others, but the huge price spread exists between these two switches because NETGEAR ProSafe GS724T has another two SFP ports for more flexible application. Among these four switches, if you have no limited cost budget, FS S3800-24F4S is a good choice. It has more flexible port combination and higher switching capacity, that is why it may cost a little more than the other three switches. If you need stronger data transferring capability, FS S3800-24F4S is a better choice considering its forwarding rate. On the contrary, TP-Link TL-SG1024 is the best budget choice. If you want a fanless switch, NETGEAR ProSafe GS724T is an inexpensive and reliable choice, but the install program only works on Windows and the secure management is very difficult to be enabled.

Conclusion

When choosing a Gigabit Ethernet switch, the first factor to consider is how many devices need to be networked together. Purchasing a network switch with too few ports and not enough capacity will prove ineffective, and one that is too large can be a waste of money. Generally, small offices with a few employees should start with a 16-port switch, but a business that is looking to expand its operations soon needs a 24-port switch. So 24-port switch is the most future-proofing and cost-effective choice in small business network. Except the above mentioned S3800-24F4S, FS.COM also provides other three cost-effective 24-port switch for different demands.

FS.COM 24-port Gigabit Switches Mode Description
S2800-24T4F Fanless Gigabit managed switch with 24 100/1000BASE-T ports and 4 combo SFP slots
S3700-24T4S Gigabit managed switch with 24 10/100/1000BASE-T ports and 4 10GE SFP+ uplinks ports
S3800-24T4S Gigabit stackable managed switch with 24 10/100/1000BASE-T ports and 4 10GE SFP+ uplinks ports

Related Article: 48-Port 10GE Switch Selection: What Is the Right Choice?

Good Forecasts for Global Optical Fiber Cable Market

An optical fiber cable uses light wave for voice and data transmission, its data transmission capacity is 4.5 times more than conventional copper cables. So in the past several decades, we have seen that fiber optic cables are superior to traditional copper twisted-pair cable or coaxial cable because of its unique physical characteristics, allowing information to travel at speeds increasingly approaching the speed of light without interference between adjacent wavelengths. In leading market, the global drive to implement FTTx into more new venues is good news for the market of optical fiber cables. Another good trend is that the price erosion of optical fiber cables had been 10 to 15 percent annually, in result that the demand of optical fiber cable is expected to continue growing in the foreseeable future. And the growing data transmission workloads placed by high-performance computers, servers and network storage systems is helping spur growth in the market. Consequently, fiber optic cables are now the indispensable backbone of today’s communication network. This article will analyse the global optical fiber cable market in three main applications, including long-distance communication, submarine cable and FTTx network.

fiber

Global Optical Fiber Cable Market to Grow at 9.8% till 2021

According to the report “Fiber Optics Market by Cable – Global Forecast to 2021”, the optical fiber cable market is anticipate to grow at a CAGR of over 9.8% during 2016-2021. The growing importance of cloud computing, data transfer & storage, and IoT is driving the use of Internet, which is driving the fiber optic cable market, as it acts as the backbone for data transmission. Moreover, growing technological advancements increase in number of connected devices and data centers are expected to positively influence global optical fiber cable market. In addition, next generation technologies such as LTE and FTTx, which require last mile connectivity, is expected to propel the demand for optical fiber cables in the coming years. All these factors have led to an increase in Internet users, which in turn has led to the higher usage of optical fiber cable to transfer information over the Internet, thus driving the fiber optics market.

Global Optical Fiber Cable Market

Global Optical Fiber Cable Demand from 2012 to 2018 (Source: Statista)

Optical Fiber Cable Market in Long-distance Communication

Currently, the growing adoption of optical technology in the telecommunications appears to be promising. Optical fiber has virtually unlimited capacity and low signal attenuation allowing long distances without amplifier or repeater, no exposure to parasite signals or crosstalk, and no electromagnetic interference (EMI). So fiber optic cable is especially advantageous for high-speed data transfer services in long-distance communications over electrical cabling. Furthermore, the increasing cloud-based applications, audio-video services, and Video-on-Demand (VoD) services further stimulate the demand for optical fiber cable installations.

Growing Need for Capacity

Growing Need for Capacity (Source: Goldmedia)

Submarine Optical Fiber Cable Market

Submarine optical fiber cables are undersea cables used for carrying data across interconnected networks between continents. With the advancements of technology, most of the submarine optical fiber cables that currently form the backbone of the Internet connect the U.S. to Europe and Asia by crossing the Atlantic or Pacific oceans. Instead, there is a proposal for deployment of Trans-polar submarine cable system in Arctic Ocean. Laying an undersea fiber optic cable is meant to connect Asia and Europe by crossing the Arctic Circle – the shortest practical distance yet for Internet signals traveling between the two continents. According to the report by Global Industry Analysts (GIA), cumulative installations of submarine optical fiber cables globally are projected to reach 2 million kilometers by 2020, driven by the growing demand for fiber broadband and the ensuing deployment of fiber optic cables in the Internet backbone. Presently, submarine optical fiber cables transmit 100% of the international Internet traffic, and more than 95% of the world’s combined data and voice traffic.

Submarine_Fiber_Cable_Market

Submarine Optical Fiber Cable Market (Source: Technavio)

Optical Fiber Cable Market in FTTx Networks

In recent years, the market for optical fiber cable has shifted dramatically to local deployments, away from long haul and regional. This is the impact of FTTx, which calls for far more dense applications in neighborhoods, cities and other highly focused areas. Optical fiber cable is being caught up in the global move to broadband in the near future. The next generation of high bandwidth applications, along with the proliferation of connected devices, is expected to require faster and higher bandwidth networks which will require the use of multimode fiber cable for data transfer. This growth in the FTTx networks in turn is expected to drive the fiber optics market. Future Market Insights (FMI) forecasts the global fiber to the home (FTTH) market’s value will grow from $9.5 billion in 2017 to more than $37 billion by the end of 2027, a 14.4% compound annual growth rate (CAGR). In the leading Asian economies, more than 44% of all homes and buildings are already directly connected to the fiber optic cable network; in North America penetration is 8.4%, in Europe 5.6%.

fiber-optic-cable-in-fttx

Final Thought

Fiber optic cable is widely used for data transmission and is increasingly being used in place of metal wires because of its efficiency and high transmission capacity. Since the use and demand for great bandwidth and fast speed, there is no doubt that fiber optic transmission will bring more opportunities and be continuously researched and expanded to cater for future demands. However, although fiber optic cable in itself is considered a long-term stable investment, it also faces huge challenge. The major restraint in the fiber optics market is the growing use of wireless communications systems in remote areas.

Related Article: The Advantages and Disadvantages of Fiber Optic Transmission

A Brief Introduction of Cisco BiDi SFP Transceiver

In the early stage of optical fiber communication, one optical fiber can only transmit signals of one wavelength. This is known as conventional two-fiber Bi-Directional communication – at least two fibers are needed to accomplish the full-duplex communication with TX and RX optical signals. With the development of WDM technology, transmitting and receiving of optical signals on separate wavelength can be achieved through only one single fiber. This single fiber BiDi transmission gradually becomes a popular and cost-effective solution for today’s data center and IT infrastructure, because it helps to maximize the capacity and usage of optical fibers. Consequently, BiDi optical transceiver as the basic component plays an irreplaceable role in the WDM BiDi transmission application. This article will generally introduce Cisco BiDi SFP transceivers, including GLC-BX-U, GLC-BX-D, GLC-BX-20U, GLC-BX-20D, GLC-BX40-D-I, GLC-BX40-U-I, GLC-BX80-D-I, GLC-BX80-U-I, GLC-BX120-U, GLC-BX120-D, etc.

Cisco BiDi SFP

What Is a BiDi SFP?

BiDi SFP transceiver can be defined as a compact, hot swappable, input/output optical module that can transmit and receive data to/from interconnected equipment through a single optical fiber. Unlike traditional optical transceivers, BiDi optical transceivers are fitted with wavelength division multiplexing (WDM) diplexers, which combine and separate data transmitted over a single fiber based on the wavelengths of the light. To simplify it, conventional optical module has two ports – the TX for the transmit port and the RX for receive port; but BiDi transceiver has only one port to complete the 1310nm optical signal transmitting and 1550nm optical signal receiving, or vice versa. Therefore, BiDi transceivers must be deployed in matched pairs with their diplexers tuned to match the expected wavelength of the transmitter and receiver. These BiDi optical transceivers can offer bi-directional data links over single-mode fiber up to 120 km. BiDi SFP transceiver is applicable to many access networks: passive optical networks (PON) and point-to-point, digital video and closed circuit television (CCTV) applications, inter-system communication between servers, switches, routers, optical add drop multiplexer (OADM), WDM fast Ethernet links, SDH/STM-1, SONET/OC3, metropolitan area networks and other optic link.

working principle of BiDi SFP

Common Types of Cisco BiDi SFP

1G BiDi SFP is also known as 1000BASE-BX SFP, which use two different wavelengths (1310nm-TX/1490nm-RX, 1310nm-TX/1550nm-RX, 1490nm-TX/1550nm-RX and 1510nm-TX/1570nm-RX) for transmission in different distance. The following will list some main Cisco BiDi SFP modules in 10km, 20km, 40km, 80km and 120km.

10km Cisco BiDi SFP

The Cisco GLC-BX-D and GLC-BX-U is a pair of 10km BiDi SFP transceiver with LC duplex connectors, operating on a single strand of standard SMF. The GLC-BX-U transceiver operates at 1310nm-TX/1490nm-RX wavelength with upstream bidirectional single fiber, while the GLC-BX-D transceiver operates at 1490nm-TX/1310nm-RX wavelength with downstream bidirectional single fiber. These two BiDi optical modules, compliant to 1000Base-BX standard, are rated for distances up to 10 km over SMF and a maximum bandwidth of 1Gbps. A 1000BASE-BX-D device is always connected to a 1000BASE-BX-U device with a single strand of standard SMF. In addition, the GLC-BX-D and GLC-BX-U BiDi SFPs also support digital optical monitoring (DOM) functions according to the industry-standard SFF-8472 multisource agreement (MSA). This feature gives the end user the ability to monitor real-time parameters of the SFP, such as optical output power, optical input power, temperature and transceiver supply voltage.

10km Cisco BiDi SFP

(GLC-2BX-U and GLC-2BX-D are 2-channel 1000BASE-BX SFP modules, also known as compact SFPs that integrate two IEEE 802.3ah 1000BASE-BX10 interfaces in one SFP module. They are designed to connect to any standard-based Customer Premises Equipment (CPE) in FTTx links.)

20km Cisco BiDi SFP

GLC-BX-20U and GLC-BX-20D are Cisco 20km BiDi SFP transceivers that work with single mode fiber. The GLC-BX-20U operates at 1310nm-TX/1550nm-RX wavelength, and GLC-BX-20D operates at 1550nm-TX/1310nm-RX. So these two BiDi SFPs always work in pairs. Their max data rate is 1000Mbps. FS.COM compatible Cisco BiDi transceivers are high performance, cost effective modules supporting data-rate of 1000Mbps and 20km transmission distance with SMF. Among the Cisco 20km BiDi SFPs, Cisco Linksys MFEBX1D provides up to 155Mbps bi-directional data transfer rate at distances up to 20km on a single fiber core. These bidirectional SFP transceivers allow data transfer in either direction through a single optical fiber by employing separate wavelengths travelling in either direction.

20km Cisco BiDi SFP

40km Cisco BiDi SFP

Cisco GLC-BX40-D-I and GLC-BX40-U-I is a pair of 40km BiDi SFP modules for Gigabit Ethernet 1000BASE-BX and Fiber Channel communications. They support link length of up to 40km point to point on single mode fiber at 1Gbps bidirectional and use an LC connector. The GLC-BX40-D-I is 1550nm-TX/1310nm-RX 40km BiDi WDM SFP simplex transceiver module, GLC-BX40-U-I is 1310nm-TX/1550nm-RX BiDi WDM SFP module. They are specified for duplex optical data communications such as 1000BASE-BX Gigabit Ethernet per IEEE802.3z and 1G Fiber Channel extended reach application.

40km Cisco BiDi SFP

80km Cisco BiDi SFP

The Cisco GLC-BX80-D-I and GLC-BX80-U-I SFPs are 1G BiDi SFP modules that provide 80km transmission distance over single strand of single-mode fiber. GLC-BX80-D-I operates at 1570nm-TX/1490nm-RX wavelength, whereas GLC-BX80-U-I operates at 1490nm-TX/1570nm-RX. These bidirectional SFP transceivers are 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 on fiber backbones. Compared with commonly used dual fiber SFP transceiver modules, the BiDi SFP transceiver allows end users to reduce the total cost on fiber cabling infrastructure by requiring half of fiber cables, providing increased transmission capacity very convenient without installing new fibers.

80km Cisco BiDi SFP

120km Cisco BiDi SFP

The Cisco GLC-BX120-U and GLC-BX120-D are 1490nm and 1550nm bidirectional SFP transceivers that are used with single mode optical fiber. They also use two wavelength 1490nm-TX/1550nm-RX(1550nm-TX/1490nm-RX) simultaneously. These BiDi SFP modules can support transmission distance up to 120 km, which are connected through pluggable LC connector type optical interface. They have a DFB (Distributed Feedback) type transmitter, an APD (Avalanche Photo-Diode) type receiver, an LD (Laser Driver), a limiting amplifier and digital diagnostic monitor. Those BiDi SFP transceivers are Class 1 laser safety product which complies with US FDA regulations, SFP MSA, SFF-8472 and RoHS standards. More importantly, 120km SFP modules have the same or even lower transmit power as compared to 80km SFP. It is the reason that 120km modules extend the range thanks to receiver not transmitter. 120km modules have much better receiving sensitivity than 80km modules.

120km Cisco BiDi SFP

Conclusion

BiDi SFP transceiver serves as an ideal and feasible solution in situations where only limited fibers or limited conduit space is available. And the deployment of BiDi optical transceivers efficiently enhances the bandwidth capacity of the existing optical fiber infrastructure and help to achieve economical and reliable performance of the optical network. Although BiDi transceivers may be more expensive than common transceiver modules, they can save you the cost on fiber cables from the long run.

Related Article: A Brief Introduction of BiDi SFP Transceiver

SFP-GE-S-2 VS. GLC-SX-MM: What’s the Difference?

SFP-GE-S-2 and GLC-SX-MM are Cisco 1000BASE-SX SFP multimode fiber transceivers. Since there are similar specifications for these two multimode modules, many end users may be confused when choosing a multimode fiber SFP LC connector SX transceiver for their Cisco switches. So, are they the same one? This post intends to give a simple explanation of SFP-GE-S-2 vs. GLC-SX-MM.

SFP-GE-S-2

SFP-GE-S-2 Module

Cisco SFP-GE-S-2 is a 1 GbE SFP SX fiber transceiver that supports the maximum data rate of 1Gbps. It’s compatible with the IEEE 802.3z 1000BASE-SX standard, and can operate on standard multimode fiber optic link spans of up to 2 km.

Module/Specs Cisco SFP-GE-S-2
Interface LC duplex
Wavelength 1310nm
Tx power -9.5 ~ -3dBm
Receiver Sensitivity < -17dBm
DOM Support Yes
Temperature Range 32℉to 158℉
(0℃ to 70℃)
Data Rat 1G
Fiber Mode MMF

GLC-SX-MM Module

GLC-SX-MM transceiver is also a Cisco GE SFP LC connector SX transceiver that designed for Gigabit Ethernet applications. This SX module is compatible with the IEEE 802.3z 1000BASE-SX standard, and can operate on standard multimode fiber optic link spans of up to 550m.

Module/Specs Cisco GLC-SX-MM
Interface LC duplex
Wavelength 850nm
Tx power -9.5 ~ -3dBm
Receiver Sensitivity < -17dBm
DOM Support No
Temperature Range 32℉to 158℉
(0℃ to 70℃)
Data Rat 1G
Fiber Mode MMF

SFP-GE-S-2 VS. GLC-SX-MM

From the above specs comparison, we can learn that these two SX multimode modules support same data rate and operating temperature range. They all can operate on the multimode fiber optic cables. The main differences include:

  • Wavelength

SFP-GE-S-2 can support a wavelength of 1310nm, whereas GLC-SX-MM works in 850nm.

  • Transmission Distance

SFP-GE-S-2 can support up to 2km over laser-optimized 50 μm multimode fiber cable, while GLC-SX-MM can operate on legacy 50 μm multimode fiber links up to 550m.

  • DOM Support

SFP-GE-S-2 can support DOM, but GLC-SX-MM does not have DOM function. DOM (Digital Optical Monitoring) 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, it offers users more convenience when using optical modules.

  • Price

GLC-SX-MM is a legacy model, it doesn’t feature DOM function. It comes with the lowest price compared with other SX modules . Take FS.COM compatible transceivers as example, SFP-GE-S-2 costs $ 11.00, while GLC-SX-MM is only $ 6.00.

Conclusion

From the contents above – SFP-GE-S-2 vs. GLC-SX-MM, we can draw a conclusion that these two SX multimode fiber transceivers nearly can be used as the same one type module sometimes, but their existing differences still differ them from some applications. Most of the Cisco switches and routers support all two models, but please note, some of the switches require different models, you may visit Cisco SFP Compatibility Matrix for more detailed information.

1000BASE-SX SFP Multimode VS. 1000BASE-LX SFP Single-mode

1000BASE-X is a group of standards for Ethernet physical layer standards, which is used for gigabit Ethernet connections that transmit data mainly over fiber optic cable or copper-shielded cable. There are several 1000BASE-X interface types used in SFP transceiver modules, including 1000BASE-SX, 1000BASE-LX and 1000BASE-EX. Besides, SFP transceivers are available with different 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 (eg: multimode fiber or single-mode fiber). 1000BASE-LX SFP and 1000BASE-SX SFP are two common types of optical transceiver modules in the market. Today’s topic will discuss 1000BASE-SX SFP multimode vs. 1000BASE-LX SFP single-mode.

sfp transceiver

1000BASE-SX SFP VS. 1000BASE-LX SFP

1000BASE-SX SFP Transceivers for Multimode Fiber Only

1000BASE-SX is a physical layer specification for Gigabit Ethernet over fiber optic cabling as defined in IEEE 802.3z. The SX systems operate full-duplex with multimode fiber only, using the cheaper 850nm wavelength laser diodes. The maximum distance supported varies between 220 and 550 meters depending on the bandwidth and attenuation of the fiber optic cable used. The standard 1000Base-SX NICs available today are full-duplex and incorporate LC fiber connectors. So 1000BASE-SX SFP supports link length of up to 550m (depending on fiber type) on multimode fiber at 1Gbps. This optic works at 850nm wavelength and uses a LC connector. Take Cisco GLC-SX-MM for example, this 1000BASE-SX SFP transceiver is able to realize 550m link length through OM2 MMF with LC duplex.

1000BASE-LX SFP Transceivers for Both Multimode and Single-Mode Fibers

As opposed to 1000Base-SX, 1000BASE-LX uses long wavelength laser over both multimode and single-mode fiber. It has a working distance of up to 10 km over single-mode optic fiber, and a maximum length of 550 meters on multimode fiber. So the 1000BASE-LX 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. Arista Networks SFP-1G-LX is 1000BASE-LX SFP transceiver that operates over a wavelength of 1310nm for 10 km on SMF and 550m on MMF.

Single-mode SFP VS. Multimode SFP

SFP modules can be divided into single-mode SFP and multimode SFP modules. For single-mode SFP modules, there are “LX” for 1310nm and “EX” “EZX” for 1550nm. Single-mode fiber SFP is designed to transmit signals over long distances. So the single-mode module works mainly in the 1310nm and 1550nm wavelengths and is mostly used in a long distances transmission environment reaching 2 km, 10 km, 40 km, 60 km, 80 km and 120 km. For example, Cisco GLC-ZX-SM is a single-mode module, which operates over a wavelength of 1550nm for 80 km.

Single-mode SFP(extraction lever):

  • LX – 1310 up to 10km
  • EX – 1310 up to 40km
  • ZX – 1550 up to 80 km using green ex lever
  • EZX – 1550 up to 160 km

Single-mode SFP VS. Multimode SFP

NOTE:

  • Black color coded bale clasp designates a Multi-mode SFP
  • Blue color coded bale clasp designates the 1310nm SFP

Comparatively, multimode SFP transceivers are identified with “SX”. This MMF SFP optics is specially for short distance data transmission. The common multimode SFP modules work in 850nm wavelength and is only used for short distance transmission reaching 100m and 500m. Though it’s not able to transport for long distance, it can transport many kinds of optical signals. For instance, Cisco GLC-SX-MMD is a typical multimode fiber transceiver, which operates over a wavelength of 850nm for 550m.

1000BASE-SX SFP Multimode VS. 1000BASE-LX SFP Single-mode

  • Standard

SX stands for short wavelength. The standard specifies a distance capability between 220 meters and 550 meters. 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 – 1355nm) 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 10 km and 550 m, respectively.

  • Types of Optical Fibers

1000BASE-LX single-mode SFP module will work with single-mode fiber in order to perform both transmission and reception of data. Whereas 1000BASE-SX multimode SFP transceiver will work with multimode fiber, which has a thicker core and allows higher speed at shorter distance.

  • Transmission Distance

1000BASE-LX single-mode SFP transceivers are mostly used in long distances (up to 10 km) transmission environment. 1000BASE-SX SFP multimode is only used for short distances (up to 550m), like in small area or within the building.

  • Wavelength

1000BASE-LX single-mode SFP works in 1310nm, whereas 1000BASE-SX SFP multimode works in 850nm.

  • Transmission Medium

1000BASE-LX single-mode SFP transport the optical signal for long distance, but there is only one signal in the “tunel”. 1000BASE-SX multimode SFP has many optical signal in one “tunel”, the signals may affect each other. So it can transport many kind of optical signals.

  • Dispersion

1000BASE-SX multimode optics are affected by modal dispersion, because the light rays follow different paths through the fiber and arrive at different times on the other end. This is the main reason the distance on this type of optic is limited. Whereas 1000BASE-LX single-mode optics are affected by wave guide dispersion, caused by the light going down the fiber being wider than the core of the fiber. This allows more control of the path of the photons, but is more affected by micro bends, twists and stress on the fiber.

1000BASE-SX SFP Multimode VS. 1000BASE-LX SFP Single-mode

Conclusion

Through 1000BASE-SX SFP multimode vs. 1000BASE-LX SFP single-mode, we could actually conclude that the 1000BASE-SX standard was developed to support lower cost multimode fiber running in horizontal and shorter-length backbone applications, while the 1000BASE-LX standard was developed to support longer-length multimode building fiber backbones and single mode campus backbones. With so many types of SFP modules available in the market, careful notice should be given to the range of differences, including transmission distance, wavelength, cable types, price, etc.

Related Article: The Basics of 1000BASE-SX and 1000BASE-LX SFP

SFP Module: What’s It and How to Choose It?

SFP 40 km VS. DWDM SFP: Which to Choose?

Small Form-factor Pluggable (SFP) is a compact, hot-pluggable transceiver used for both telecommunication and data communications applications. It is also called mini-GBIC for its smaller size, which is the upgraded version of GBIC transceiver. These 1Gb SFP modules are capable of supporting speeds up to 4.25 Gbps. And they are most often used for Fast Ethernet of Gigabit Ethernet applications. It interfaces a network device motherboard (for a switch, router, media converter or similar device) to a fiber optic or copper networking cable. SFP modules are commonly available in several different categories: 1000BASE-T SFP, 1000BASE-EX SFP, 1000BASE-SX SFP, 1000BASE-LX/LH SFP, 1000BASE-BX SFP, 1000BASE-ZX SFP, CWDM SFP and DWDM SFP. These modules support different distance according to the different Gigabit Ethernet standard. Today’s main subject will discuss SFP 40 km vs. DWDM SFP.

FS.COM Optical Transceivers

SFP 40 km

SFP 40 km transceiver is designed for highly reliable fiber optic network links up to 40 km. It is a cost effective transceiver designed to enable 1Gb for data center and core network applications. 1000BASE-EX SFP is the most popular SFP 40 km transceiver which runs on 1310nm wavelength lasers and achieves 40km link length. Except that, 1000BASE-BX BiDi SFP, 1000BASE-LH SFP and 1000BASE-LX SFP can also realize the transmission distance up to 40 km. The following will introduce these 1GbE SFP 40 km transceivers respectively.

1000BASE-EX SFP 40 km

1000BASE-EX SFP transceiver module is designed to connect a Gigabit Ethernet port to a network and has dual LC/PC single mode connectors. It operates on standard single-mode fiber-optic link spans of up to 40 km in length. The SFP Ethernet module provides a dependable and cost-effective way to add, replace or upgrade the ports on switches, routers and other networking equipment. Cisco GLC-EX-SM1550-40 and Cisco GLC-EX-SMD are 1G single mode fiber SFP 40 km modules for 1000BASE-EX Gigabit Ethernet transmission. GLC-EX-SM1550-40 supports a 1550nm wavelength signaling, while GLC-EX-SMD supports a 1310nm wavelength signaling.

SFP 40 km

1000BASE-BX SFP 40 km

1000BASE-BX SFP is a kind of BiDi transceiver, which can be divided into 1000BASE-BX-D SFP and 1000BASE-BX-U SFP. These two SFP transceivers must be used in pairs to permit a bidirectional Gigabit Ethernet connection using a single strand of single mode fiber (SMF) cable. The 1000BASE-BX-D SFP operates at wavelengths of 1490nm TX/1310nm RX, and the 1000BASE-BX-U SFP operates at wavelengths of 1310nm TX/1490nm RX.

  • 1000BASE-BX-D BiDi SFP 40 km

Cisco GLC-BX40-D-I and GLC-BX40-DA-I are pluggable fiber optical transceivers for Gigabit Ethernet 1000BASE-BX and Fiber Channel communications. They support link length of up to 40 km point to point on single mode fiber at 1Gbps bidirectional and use an LC connector. The GLC-BX40-D-I transceiver transmits a 1490nm channel and receives a 1310nm signal, whereas GLC-BX40-DA-I transmits at a 1550nm wavelength and receives a 1310nm signal.

  • 1000BASE-BX-U BiDi SFP 40 km

Similar to 1000BASE-BX-D 40 km SFP , Cisco GLC-BX40-U-I and GLC-BX40-UA-I also support link length of up to 40 km point to point on single mode fiber at 1Gbps bidirectional and use an LC connector. The main difference is the wavelength: GLC-BX40-U-I transmits a 1310nm channel and receives a 1550nm signal, whereas GLC-BX40-UA-I transmits at a 1310nm wavelength and receives a 1490nm signal. A GLC-BX40-D-I or GLC-BX40-DA-I device connects to a GLC-BX40-U-I or GLC-BX40-UA-I device with a single strand of standard SMF with an operating transmission range up to 40 km.

1000BASE-LX SFP 40 km

1000BASE-LX is a standard specified in IEEE 802.3 Clause 38 which uses a long wavelength laser. 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 – 1355nm) over long cable runs of fiber optic cabling. Allied Telesis AT-SPLX40 and Allied Telesis AT-SPLX40/1550 are 1000BASE-LX SFP single-mode modules supports Gigabit Ethernet over single-mode cables at distances up to 40 km. AT-SPLX40 operates over a wavelength of 1310nm for 40 km, whereas AT-SPLX40/1550 operates over a wavelength of 1550nm.

1000BASE-LH SFP 40 km

Unlike 1000BASE-LX, 1000BASE-LH is just a term widely used by many vendors. Long Haul (LH) denotes longer distances, so 1000BASE-LH SFP modules operate at a distance up to 70 km over single mode fiber. Cisco Linksys MGBLH1 is a easy-to-install modules that provide a simple way to add fiber connectivity or to add an extra Gigabit Ethernet port to switches. The MGE transceiver can support distances up to 40 km over single-mode fiber at a 1310nm wavelength.

DWDM SFP

DWDM SFP transceivers are used as part of a DWDM optical network to provide high-capacity bandwidth across an optical fiber network, which is a high performance, cost effective module for serial optical data communication applications up to 4.25Gb/s. DWDM transceiver uses different wavelengths to multiplex several optical signal onto a single fiber, without requiring any power to operate. There are 32 fixed-wavelength DWDM SFPs that support the International Telecommunications Union (ITU) 100-GHz wavelength grid. The DWDM SFP can be also used in DWDM SONET/SDH (with or without FEC), but for longer transmission distance like 200 km links and Ethernet/Fibre Channel protocol traffic for 80 km links. Cisco C61 DWDM-SFP-2877-40 is a 1000BASE-DWDM SFP 40km transceiver, which is designed to support distance up to 40 km over single-mode fiber and operate at a 1528.77nm DWDM wavelength (Channel 61) as specified by the ITU-T.

DWDM SFP

SFP 40 km VS. DWDM SFP

  • Transmission Medium

Generally, the standard SFP 40 km transceivers transmit through the single mode fiber, while DWDM SFP carries signals onto a single optical fiber to achieve maximum distances by using different wavelengths of laser light. So the DWDM SFP transceivers do not require any power to operate.

  • Wavelength

The standard SFP 40 km transceivers support distances up to 40 km over single-mode fiber at a 1310nm/1550nm wavelength. (the BiDi SFP has 1490nm/1550nm TX & 1310nm RX or 1310nm TX & 1490nm/1550nm RX ). However, DWDM SFP operates at a nominal DWDM wavelength from 1528.38 to 1563.86nm onto a single-mode fiber. Among them, 40 km DWDM SFP operates at a 1528.77nm DWDM wavelength (Channel 61).

  • Application

DWDM SFP is used in DWDM SONET/SDH, Gigabit Ethernet and Fibre Channel applications. These modules support operation at 100Ghz channel. The actual SFP transceiver offers a transparent optical data transmission of different protocols via single mode fiber. And for back-to-back connectivity, a 5-dB inline optical attenuator should be inserted between the fiber optic cable and the receiving port on the SFP at each end of the link.

  • Price

DWDM provides ultimate scalability and reach for fiber networks. Boosted by Erbium Doped-Fiber Amplifiers (EDFAs)  – a sort of performance enhancer for high-speed communications, DWDM systems can work over thousands of kilometers. Most commonly, DWDM SFP is much more expensive than the standard SFP. You can see the price more clearly in the following cable.

SFP 40 km VS. DWDM SFP

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. Through SFP 40 km vs. DWDM SFP, if you are looking for SFP modules over long distance and with better scalability, DWDM SFP module is the ideal choice.

Related Article: SFP Transceiver: To Be or Not To Be?

EPON SFP VS. GPON SFP: Cost-effective Solution for Access Network

With the increasing demands for higher capacity, more diversity and more personalization of services, the capacity and versatility of access networks needs to be expanded. Passive optical network (PON), as a major technology of FTTH, offers point-to-multipoint (P2MP) network access with lower installation and maintenance costs. EPON (Ethernet PON) and GPON (Gigabit PON) are popular versions of PONs at present. The related technologies keep developing and meanwhile the market of PON components keep growing. PON transceiver (EPON SFP or GPON SFP) is an essential part of PON system, in which a single fiber from a central office optical network unit (ONU) is connected to optical network terminals (ONTs) or optical network units (ONUs) at costomer premises. EPON SFP vs. GPON SFP is today’s main subject matter of this paper.

EPON SFP VS. GPON SFP

Passive Optical Network (PON)

Passive optical network (PON) is a form of fiber-optic access network. As the leading technology being used in FTTx (FTTH) deployments, so it is also called FTTH (fiber to the home) network. The typical PON arrangement is a point to multi-point (P2MP) network where a central optical line terminal (OLT) at the service provider’s facility distributes TV or Internet service to as many as 16 to 128 customers per fiber line. A PON reduces the amount of fiber and central office equipment required compared with point-to-point architectures. PON only uses fiber and passive components, thus it costs significantly less than those using active components. However, a PON has a shorter range of coverage limited by signal strength, which is typically limited to fiber cable runs of up to 20 km (12 miles). There are two different solutions developed by the IEEE and ITU-T – EPON and GPON. The main differences between them lie in the protocols used for upstream and downstream communications. The following table shows the detailed information about EPON vs. GPON.

EPON vs. GPON

Table 1: EPON vs. GPON

What Is PON Transceiver?

PON transceiver is a bi-directional optical transceiver that uses different wavelengths to transmit and receive signals between the OLT at the CO and the ONUs at the end users’ premises over a single fiber. According to the pluged-in device, PON transceiver can be divided into OLT transceiver module and ONU transceiver module with SFF, SFP/SFP+ or XFP package. Here mainly introduce two common OLT transceivers used in GPON or EPON network: GPON SFP and EPON SFP.

GPON SFP

GPON SFP

GPON SFP OLT transceiver is designed for OLT side in GPON network. GPON SFP uses 1490nm continuous-mode transmitter and 1310nm burst-mode receiver. The transmitter section uses a 1490nm DFB (Distributed Feed Back) LD with automatic power control (APC) function and temperature compensation circuitry to ensure stable extinction ratio overall operating temperature range. And it is Class I laser compliant IEC825 and CDRH standards. The receiver has a hermetically packaged burst-mode APD-TIA (trans-impedance amplifier) pre-amplifier and a burst-mode limiting amplifier with LVPECL compatible differential outputs. The GPON OLT SFP transceiver is a high performance and cost-effective module for serial optical data communication applications to 2.5Gpbs. For GPON transceivers, there are 2 Class available – Class B+ and Class C+. The table below shows the key differences between GPON SFP class B+ and class C+:

GPON SFP class B+ vs. class C+

Table 2: GPON SFP class B+ vs. GPON SFP class C+

EPON SFP

EPON SFP transceiver is the family of high performance optical modules providing a symmetric 1.25 Gb/s downstream and 1.25 Gb/s upstream data link over a single fiber using a 1490 nm continuous-mode transmitter and 1310 nm burst-mode receiver. The transmitter section uses a 1490nm DFB laser for superior performance and is Class 1 laser compliant. The receiver section uses a 1310nm APD, pre-amplifier, and limiting post-amplifier. The receiver does not require a reset pulse between incoming optical packets of varying signal strength. EPON SFP OLT transceivers support 1000BASE-PX20-D for 20 km applications.

EPON SFP VS. GPON SFP

In terms of OLT module, there are many similarities through EPON SFP vs. GPON SFP, such as type of laser, transmission distance and communication model. The key difference among them is the sending power and receiver sensitivity. The sending power of GPON SFP Class B+ is 1.5~5dBm, and its receiver sensitivity is -28dBm while the sending power of Class C+ is 3~7dBm and receiver sensitivity is -32dBm. The sending power of EPON SFP is 2~7dBm and its receiver sensitivity is -28dBm. For GPON SFP, the upstream bandwidth is scalable from 155Mbps to 2.5Gbps while the downstream is designed to deliver 1.25Gbps or 2.5Gbps. It is the most widely used consumer broadband service in FTTH networks of present times. On the other hand, EPON SFP supports symmetric bandwidth of 1.25Gbps in both the upstream and downstream directions.

EPON SFP VS. GPON SFP

Table 3: EPON SFP vs. GPON SFP

Conclusion

Through EPON SFP VS. GPON SFP, we can see that they are the same in architecture but for different data rate and applications. In terms of cost, The GPON SFP optical module is more expensive than EPON SFP. Because the GPON chipsets available in the market are mostly based on FPGA (Field Programmable Gate Array), which is more expensive than the EPON MAC (Media Access Control) layer ASIC. When GPON reaches deployment stage, the estimated cost of a GPON OLT is 1.5 to 2 times higher than an EPON OLT. For the users who have demands of multi-service, high QoS and security, as well as ATM backbone network, GPON SFP seems to be an ideal. And for the one who is much care about the cost and has less security requirements, EPON SFP may be better.

Related Article: Passive Optical Network Tutorial

Where to Buy Reliable Low Cost 1000BASE-T SFP Modules?

Gigabit Ethernet, as a part of the Ethernet family of computer networking and communication standards, has been in the market for more than 15 years. 1000BASE-T Gigabit Ethernet is the most successful networking technology in the history. Delivering Gigabit performance over up to 100 meters of twisted pair cabling (Cat5 UTP), it is ideal solution to upgrade network smoothly without change its original architecture and decrease the cost of upgrading for a wide range of enterprise and embedded networking applications. When investing in 1000BASE-T SFP modules to keep the highest working quality for business, everyone wants to find the best deals when they come to their network hardware, but also with the same compliance certification and quality. So where to buy reliable low cost 1000BASE-T SFP modules? This article will tell you answer.

1000BASE-T SFP

1000BASE-T SFP for Copper Networks

1000BASE-T SFP copper transceiver is based on the SFP Multi Source Agreement. It is compatible with the Gigabit Ethernet and 1000BASE-T standards as specified in IEEE 802.3z and 802.3ab. This Gigabit RJ45 copper SFP transceiver module supports 1000Mbps over Cat5 cables with RJ45 connector interface, which operates on standard Cat5 unshielded twisted-pair copper cabling of link lengths up to 100 m (328 ft). So those 1G copper SFPs can plug into any standard SFP interface allowing for 1000BASE-T Gigabit transmission. When referring to the types of 1000BASE-T copper SFP modules, there are generally three types provided by Cisco: Cisco GLC-T, Cisco GLC-TE, Cisco SFP-GE-T.

Cisco GLC-T

GLC-T is the Cisco 1Gb copper SFP, which is compliant to IEEE 802.3, and operates over Cat5 copper wire for a distance of 100m. It provides 1Gbps data transfer and full-duplex Gigabit Ethernet connectivity to high-end workstations and between wiring closets over existing copper network infrastructure.

Cisco GLC-T

Cisco GLC-TE

Similar to GLC-T SFP modules, GLC-TE provides a link length of 100m over Cat5 copper wires. The only difference between these two SFP modules lies in the operating temperature range. GLC-T SFP is commercial temperature range (COM) from 0 to 70°C (32 to 158°F), while GLC-TE is Extended temperature range (EXT) from -5 to 85°C (23 to 185°F).

Cisco SFP-GE-T

SFP-GE-T is Cisco copper SFP transceiver that works with 1000BASE-T. This 1Gb SFP RJ45 module is with spring latch for high density applications. The most difference is that SFP-GE-T has the function of NEBS 3 ESD. (NEBS is short for Network Equipment Building System and is a set of standards for building networking equipment which can withstand a variety of environmental stresses.) Therefore, SFP-GE-T supports extended working temperature.

Where to Look for Compatible Cisco 1000BASE-T SFP?

There are all sorts of resources to get the most out of technology budget, especially when it comes to find the Cisco 1000BASE-T SFP modules either for brand new, refurbished, or gently used. What are the best ways to find them for a much more inexpensive price?

  • Online Retailers

Online retailers with warehouses not only provide consumer-side purchasing with modules and networking hardware, they can also be a valuable asset to all sorts of companies looking to spend less money on equipment. There are online retailers that give almost as high as 90% discounts and price reductions. You need to be careful when it comes to certain warehouses as they might have huge savings but the parts might be used or not of the highest quality.

  • Certified Sellers

Certified sellers, or re-sellers, can offer brand new or refurbished modules with great prices. Besides, they have professionals who can help you with all of your technology questions and make sure that you get the best deal.

  • Third-Party Companies

In fact, there are many third party vendors to manufacture compatible SFP modules, such as FS.COM, 10GTek, Finisar, Fluxlight etc. Many people are confused about whether I should use 3rd party SFP modules. Most “third party” transceivers are made and assembled in exactly the same plants assembling officially-branded transceivers. There is almost no big difference between an official Cisco transceiver and a third-party plug, aside from the branding and about two hundred to a few thousand bucks. And now, using 3rd party SFP modules seems to more and more popular, as many 3rd party SFP module vendors are providing high quality and reliable 3rd party SFP modules with low prices. Besides, third-party SFPs can be as reliable as official OEM products.

Copper SFP Models Description Operating Temperature Range FS.COM Price Fluxlight Price
Cisco GLC-T 1000BASE-T SFP Copper RJ-45 100m Transceiver COM $ 21.00 $ 44.00
Cisco GLC-TE 1000BASE-T SFP Copper RJ-45 100m Transceiver EXT $ 21.00 $49.00
Cisco SFP-GE-T 1000BASE-T SFP Copper RJ-45 100m Transceiver NEBS 3 ESD EXT $ 21.00 $44.00

Conclusion

The 1000BASE-T SFP copper transceiver offers a flexible and simple method to be installed into SFP MSA compliant ports at any time with no interruption of the host equipment operation. It enables for seamless integration of fiber with copper LAN connections wherever SFP interface slots can be found. Such system is economical, it saves time, offers flexibility and eliminates the necessity for replacing entire devices once the customers have to change or upgrade fiber connections and you will benefit so much from it.

Related Article: GLC-T vs GLC-TE vs SFP-GE-T: Which One to Choose?

Related Article: A Quick Overview of Cisco 1000BASE-T GLC-T SFP Copper Module