Does Multimode SFP Work Over Single-mode Fiber Cable?

When you prepare to connect some SFPs with fiber patch cords, you may find SFPs are multimode modules while your fiber cables are single-mode. Try to connect those optics to fiber cable, but no green light and the link fails. So multimode SFPs can’t work over single-mode fiber cables. To avoid the wasting of time and money, you should better know well about single-mode and multimode SFPs and fiber patch cords.

Single-mode and Multimode SFP

SFP, small form factor pluggable transceiver, can support the data rate up to 1Gbps. SFPs can be divided into single-mode and multimode modules.

For single-mode SFPs, there are “LX” for 1310 nm and “EX” “EZX” for 1550 nm. Single-mode SFPs are designed to transmit signals over long distances. For example, Cisco GLC-LH-SM-15 compatible 1000BASE-LX/LH SFP 1310nm 15km DOM transceiver, main product information is shown as follows:

• Wavelength: 1310 nm
• Interface: LC duplex
• Max Cable Distance: 15 km
• Max Data Rate: 1000Mbps
• Cable Type: SMF

Comparatively, multimode SFPs are identified with “SX”. This kind of optics is specially for short distance data transmission. For instance, Cisco GLC-SX-MM compatible 1000BASE-SX SFP 850nm 550m transceiver, this is a typical multimode SFP.

• Wavelength: 850 nm
• Interface: LC duplex
• Max Cable Distance: 550m over OM2 MMF
• Max Data Rate: 1000Mbps
• Cable Type: MMF

Single-mode Fiber Cable and Multimode Fiber Cable

Fiber patch cables are used to connect transceivers on your switch/device. You have to buy the right fiber cable type for your optics. Fiber cable has two different categories: single-mode and multimode.

Generally, single-mode fiber cable can support further distance because of lower attenuation, but the price is higher. While multimode fiber cable has a larger core, usually multimode fiber cable is constructed in 50/125 and 62.5/125. It allows multiple modes of light to propagate. When the light passes through the core, the light reflections increases and more data can be transmitted at given time. As the high dispersion during signal transmission, the link distance gets reduced. So multimode fiber cable is for short distance application. Multimode fiber cable is a little more complex than single-mode fiber cable since it includes four different types of OM1, OM2, OM3, OM4. OM1 and OM2 fiber patch cable can support the data rate up to 10Gbps. OM3 and OM4 are laser optimized so that they can be used in high density data center to support the data rate of 40Gbps and 100Gbps. The following table shows how long each kind of fiber cable can reach running at different data rate.

Note: “SR” implies multimode 10Gpbs SFP+.
For more information about single-mode and multimode fiber cable, you can refer to my previous articles:
What Is Single Mode Fiber?
What Are OM1, OM2, OM3 and OM4?

Solutions for Multimode SFP
If you have Cisco Catalyst 3650 WS-C3650-48PS switches with 4x1G uplink ports, to build a 300m-network link, you are gonna purchase fiber patch cable and SFP modules. What kind of optical equipment should you choose?

As to the SFP module, you need Cisco GLC-SX-MM 1000BASE-SX SFP. Or you can spend less money on third-party SFPs with 100% compatibility. Next step, you need to find suitable fiber patch cable to match this type of SFP. Since 1000BASE-SX SFP is multimode, of course you need multimode fiber cable. Considering the distance of 300 meters, OM1 can only reach 275 meters. So OM2 is the best choice for it’s the cheapest and can reach 550 meters.

Conclusion

It’s obvious that multimode SFPs can’t work over single-mode fiber cables. When buying SFPs, watch the standards on the label carefully and find if it’s “SX” or “LX”, “EX”. If it shows “SX”, then find multimode fiber patch cable. It’s not very difficult to choose right cable for your SFP modules.

Originally published at www.fiber-optic-equipment.com

Transceiver Solutions for Ubiquiti UniFi Switches

UniFi switch is one type of the switches Ubiquiti has introduced into the market (The other kind is Ubiquiti EdgeSwitch). The UniFi switch provides fiber connectivity options for easy expansion of your networks. This article will introduce the main features of UniFi switches, supportable SFP and SFP+, and easy tips for building network with UniFi switch.

Introduction to UniFi Switches

UniFi switch delivers high performance to satisfy your growing network. The Ubiquiti UniFi switches include US-24 and US-48. US-24 can support data rates up to 26 Gbps while US-48 can support the network speed up to 70 Gbps of non-blocking throughput. Main features of these two switches are described as below.

Features of US-24 switch:

• 24 Gigabit RJ45 ports
• 2 SFP ports
• 52Gbps switching capacity
• 250W max. power consumption
• Rack mountable

Features of US-48 switch:

• 48 Gigabit RJ45 ports
• 2 SFP+ ports
• 2 SFP ports
• 140Gbps switching capacity
• 56W max. power consumption
• Rack mountable

Except the above two switches, there are some other kinds containing US-8-150 (with 8 Gigabit RJ45 ports and 2 SFP ports) and US-16-150W (with 16 Gigabit RJ45 ports and 2 SFP ports). Both switches are available with different models. You can find the details about these models from the following table.

SFP and SFP+ for UniFi Switch

If you are wondering which SFP and SFP+ are suitable for UniFi switch, you can get the answer now. You have two choices for getting suitable transceiver modules. Ubiquiti produces single-mode and multimode SFP and SFP+ modules for UniFi switches. UF-MM-1G and UF-MM-1G-S are designed for SFP ports. Three modules such as UF-SM-10G, UF-SM-10G-S, and UF-MM-10G are appropriate for SFP+ ports.

Of course, transceiver modules for UniFi switch are not limited to these original SFP/SFP+. A wide range of third-party transceivers can also work with UniFi switch. The following table will show you some compatible transceivers from FS.COM.

Fiberstore SFPs

ID #	Description
20363	Cisco GLC-SX-MM-RGD Compatible 1000BASE-SX SFP 850nm 550m DOM Transceiver
11774	Cisco GLC-SX-MM-RGD Compatible 1000BASE-SX SFP 850nm 550m DOM Transceiver
32658	Finisar FTLF1318P3BTL Compatible 1000BASE-LX and 1G Fibre Channel SFP
16450	Finisar FTLF8519P2BNL Compatible 2G Fibre Channel SFP 850nm 300m EXT DOM Transceiver
14951	Finisar FTLX1371D3BCL Compatible 10GBASE-LRM SFP+ 1310nm 220m DOM Transceiver
16453	Finisar FTLF8524P2BNL Compatible 4G Fibre Channel SFP 850nm 150m EXT DOM Transceiver
32140	HPE J4858C Compatible 1000BASE-SX SFP 850nm 550m DOM Transceiver

Fiberstore SFP+s

ID #	Description
48895	1m Brocade 10G-SFPP-TWX-0101 Compatible 10G SFP+ Active Direct Attach Cable
36671	1m Brocade 10G-SFPP-TWX-0101 Compatible 10G SFP+ Passive Direct Attach Cable
30849	1m Cisco SFP-H10GB-CU1M Compatible 10G SFP+ Passive Direct Attach Copper Twinax Copper Cable
48884	1m Cisco SFP-H10GB-ACU1M Compatible 10G SFP+ Active Direct Attach Copper Cable
14945	Finisar FTLX8571D3BCL Compatible 10GBASE-SR/SW SFP+ 850nm 300m DOM Transceiver

Building Connection

To build the UniFi network, you have to prepare installation screwdriver, at least 1U rack, UTP Cat 5 (or above) for indoor applications and STP Cat5 (or above) for outdoor applications. It’s quite easy.

• First, install the UniFi switch on the rack with four mounting screws. Then plug one end of the power cord into the power port of the UniFi switch and the other end into the power outlet.
• Second, connect Ethernet cables from your devices to RJ45 ports of UniFi switch.
• Third, plug an SFP transceiver into the SFP port if you need to use it. After that, connect the SFP module with a fiber patch cable.

Conclusion

UniFi switches are very commonly used for network connection. To build the network, you don’t need to spend much time on searching cables or modules from the internet. FS.COM offers fiber patch cables and Ethernet cables for your connection. We also provide some transceiver modules definitely compatible for UniFi switch. Every module has been strictly tested to make sure high quality. Just come to our site and you must get the transceiver module you need for your UniFi switch.

Originally published at www.fiber-optic-equipment.com

Quick Guides on 3G Digital Video SFPs

As high definition (HD) content occupies the norm in video and broadcasting industry, higher standards digital video SFPs are needed for HD or even higher standard video transmission. So there are 3G digital video SFPs suitable for SD/HD/3G-SDI. To know more about 3G digital video SFPs, please continue to read this article.

SDI Standards

SDI, short for Serial Digital Interface, is a digital video interface standard made by SMPTE (The Society of Motion Picture and Television Engineers) organization. The serial interface transmits the data through single channel. Additional SDI standards include HD-SDI, 3G-SDI, 6G-SDI, and 12G-SDI. HD-SDI was standardized by SMPTE 372M in 1998. It can support 1.485Gbps interface. 3G-SDI consists of a single 2.970Gbps serial link that allows replacing dual link HD-SDI.

3G Digital Video SFPs

3G Video SFP is also named Digital Video SFP. Digital video SFP modules are specially applied for SDI (Serial Digital Interface) data rates from 50 Mbps to 3 Gbps with links of 80 km over single-mode fiber. This kind of SFPs are designed to transmit optical serial digital signals as defined in SMPTE 297-2006, specifically for robust performance in the presence of SDI pathological patterns for SMPTE 259M, SMPTE 344M, SMPTE 292M and SMPTE 424M serial rates.

Digital video SFPs are hot pluggable, easy to use, and offer the highest density optical solution for carrying digital video through optical fiber. The digital video SFP pinout is designed as one slot can be populated with a dual transmitter, dual receiver, single transmitter, single receiver, or a transceiver. Digital video SFP is a cost-effective way to solve the problems during digital video optical transmission, allow the transport of SDI and HD-SDI video signals over any optical transport system that employs MSA standard optical transceivers.

3G Digital Video SFPs Types

3G digital video SFPs include 3G SDI SFP, BiDi SFP and CWDM SFP. According to different standards, it can be divided into different types. Based on the transmission mode, it can be divided into single Tx, single Rx, dual Tx, dual Rx and TR transceivers; by standards into MSA and non-MSA; by operating wavelength into 1310nm, 1490nm, 1550nm and CWDM wave length. 3G digital video SFPs also have 3G video SFP and 3G video pathological patterns due to different applications. Let’s take a look at the details about 3G video pathological patterns SFP.

What are 3G-SDI pathological patterns? Pathological patterns, also called SDI proving ground, are a whole test signal. And it must be done during blackout. This signal is tough to handle by serial digital system, and significant to check the system performance. Pathological patterns often contain the richest low-frequency energy which statistically happens one per frame. Pathological patterns test is also an important indicator of video SFP modules. FS.COM 3Gbps video pathological patterns SFPs are used to transmit optical serial digital signals at the serial rates of SMPTE 259M, SMPTE 344M, SMPTE 292M and SMPTE 424M defined in SMPTE 297-2006. 3Gbps video pathological patterns SFPs with LC interface can transmit optical signals from 50Mbps to 3Gbps reaching the maximum distance of 40km. Both single-mode and multimode video pathological patterns SFPs are available. All modules are hot-pluggable and compatible with SFP MSA. Besides, they can be applied in 3G-SDI/HD-SDI/SD-SDI electrical-optical converter, 3G-SDI/HD-SDI/SD-SDI optical-electrical converter, HD camera or monitor system and high-density digital video routers & switches.

Conclusion

From this article, you must know some information about 3G digital video SFP. Fiberstore offers a full series of low cost but high quality 3G digital video SFPs for your applications covering the link distance of 300 m, 10 km, 20 km, 40 km and 80 km. As the advent of 4K (ultra high definition) market, the demand is growing fast for transporting the 4K in an efficient way. So just expect 6G-SDI or even 12G-SDI products researched and developed by FS.COM.

Originally published at www.fiber-optic-equipment.com

SFP+ Fiber Module or 10GBASE-T SFP+ for 10GbE Network?

The dramatic growth in data center requires the higher-performance servers, storage and interconnects. From initial 100M, 1G, 10G, to 40G and 100G, high speed Ethernet has never stopped developing. The standard for 10 Gigabit Ethernet (IEEE802.3ae) was ratified in 2002. In 10 Gigabit Ethernet, engineers often find it puzzled to choose a more suitable physical media between fiber and copper. Take a look at the media options for 10GbE Network.

Media Options for 10GbE Network

SFP+ Fiber Module

SFP+ (small form-factor pluggable plus) supports both fiber optic cables and DAC (direct attach cable). It delivers a wide variety of 10GbE Ethernet connectivity options for data center, enterprise wiring closet, and service provider transport applications. But it has the limitations that will prevent the media from moving to every server.

10GBASE SFP+ DAC

10G SFP+ cable is designed for 10GbE access layer interconnection in data center. It includes direct attach copper cables and active optical cables. DAC is a lower cost alternative to fiber, but it can support limited transmission distance and it’s not backward-compatible with existing GbE switches. DAC requires the purchase of an adapter card and requires a new top of rack (ToR) switch topology. DAC is more expensive than structured copper channels, and cannot be field terminated.

10GBASE-T SFP+

10GBase-T SFP+ enables 10GbE connections with unshielded or shielded twisted pair cables over distances up to 100 meters. 10GBase-T technology appears as SPF is not compatible with twisted pair cabling system typically used in data centers. With 10GBase-T SFP+, the migration from 1GbE to 10GbE can be easily achieved.

Comparison of SFP+ Fiber Module and 10GBase-T SFP+

Latency

Low latency becomes so important since the adoption of private cloud applications increases. It’s beneficial for ensuring fast response time and reducing CPU (center processing units) idle cycles so that improve data center efficiency.

As to 10GBASE-T SFP+, the physical connection (PHY) standard uses block encoding to transport data across the cable without errors. The block encoding requires a block of data to be read into the transmitter PHY, a mathematical function run on the data before the encoded data are sent over the link. It happens the same on the receiver side. This standard specifies 2.6 microseconds for the transmit-receive pair, and the block size requires latency to be less than 2 microseconds. While SFP+ fiber module applies simplified electronics without encoding, and common latency is around 300 nanoseconds per link.

You may think that two microseconds are not high. But what if a TOR infrastructure where traffic is passing 4 hops to reach the destination? 10.4-microsecond delay will be caused when using 10GBASE-T SFP+. The following table tells details about the latency of SFP+ DAC, SFP+ fiber module and 10GABSE-T SFP+ for different number of links.

Number of Links	SFP+ DAC Latency	SFP+ fiber Module Latency	10GBASE-T SFP+ Latency
1	0.3	0.1	2.6
2	0.6	0.2	5.2
3	0.9	0.3	7.8
4	1.2	0.4	10.4
5	1.5	0.5	13.0
6	1.8	0.6	15.6

From the above table, it shows that the latency of 10GBASE-T SFP+ is the highest. As network links grow, the latency turns to be higher. It’s known that the lower latency, the faster the network speed. High latency in the data center infrastructure results in delays in CPU and application works, therefore limiting data center efficiency and increasing operational costs.

Power Consumption

Power consumption is also one of the important factors to be considered in data centers. Engineers are sensitive to power consumption and find a way to seek the lowest possible power consumption technologies. It’s said that every watt of power consumed, typically two additional watts are needed for cooling.

10GBase-T components today require anywhere from 2 to 5 watts per port at each end of the cable depending on the distance of the cable. But SFP+ fiber module requires about 0.7 watt regardless of distance. The figure below compares the power consumption of three media options of 10GbE Ethernet.

From this figure, suppose there are 10000 ports in the data center, SFP+ fiber modules can greatly save the power. On contrary, 10GBASE-T components consumes the most power. Thus, to save power in the data center, SFP+ fiber modules and SFP+ DAC should better be selected when deploying thousands of cables in a data center.

Conclusion

From this article, SFP+ fiber modules and SFP+ DAC solutions are better than 10GBASE-T SFP+ for 10G data center. But 10GbE is not the ultimate goal. Besides factors mentioned in this article, you should also select a cabling solution which can support not only current needs but also future data center deployments when you design 10GbE network.

Originally published at www.fiber-optic-equipment.com

Brief Analysis on Fibre Channel Technology

Fibre Channel is a set of advanced data transport standards that allow large amounts of data to be moved at multi-gigabit speeds between computers, servers, and other devices. Fibre Channel is widely applied because its high bandwidth, proven reliability and some other benefits. This article will talk about Fibre Channel information.

“Fibre” and “Fiber”

You must be confused the name of this standard. Why is it called “Fibre Channel” instead of
“Fiber Channel”? The words “Fiber” and “Fibre” have the same meaning (“Fiber” is the international English spelling style, while “Fibre” is British style). “Fibre Channel” is the official spelling for the technology. “Fiber” just means the transmission media used in optical connections. The term “Fibre” is used by the Fibre Channel standard to refer to all the supported physical media types.

Fibre Channel Development History

Fibre Channel started in the late 1980s as part of the IPI (intelligent peripheral interface) to increase the capabilities of the IPI protocol. Fibre Channel was approved in 1988. The development of Fibre Channel standards serves as a model for the creation of modern transfer technology. From the beginning to its approval, it has gone through a number of iterations. Since it became more interoperable with other protocols and devices, it finally got the approval of American National Standards Institute (ANSI) in 1994.

At first, Fibre Channel was used in banks, large companies, and data centers. The installation is too complex especially when the transmitting media is optical fiber. But that bad situation has been changed. Today Fibre Channel seems to be a good choice for organizations with growing data storage needs.

Fibre Channel Benefits

Fibre Channel is more likely to be a high-speed switching system that interconnects local devices. Fibre Channel has the benefits of high speed, easy scalability, and attainable network lengths.

• High speed. Fibre Channel can provide consistent bandwidth of 2 Gbps or 4 Gbps. The rate is expected to double in a few years to 8 Gbps. It will meet the increasing needs of network users.
• Scalability. Fibre Channel networks perform with equal reliability, high rates, and flexible configuration. So it’s scalable up to thousands of ports even though device connections consist hundreds of integrated servers from different vendors.
• Guaranteed in-order delivery. Fibre Channel in-order delivery of raw block data. In-order delivery greatly boosts network efficiency. And some applications like video and IP streaming require this. Fibre Channel can naturally streams video frames in order, reducing bottlenecks that would degrade the video’s required speed per second.

Fibre Channel Deployment

A successful network deployment requires a lot. You must first know your needs and decide which type of Fibre Channel is the best suitable for your network. Is it a new network or an additional one? What’s the total physical length of the network? How many devices? To answer these questions, you may consider the cabling and connector type.

Cable — Copper or Fiber

It’s important to choose the right cable type for your network interconnection. To choose copper or fiber, it depends on the distances between the Fibre Channel devices being about to be connected.

Copper cable can be used for short distance. It’s typical in point-to-point and other topologies when devices are mounted in the same rack or are located in the same room. Copper cable is durable and can withstand being stepped on or pulled. It’s easy for installation and maintenance.

While, fiber optic cable is for long distance since the distance between devices become longer than before, maybe in different buildings or on different floors of a building. Compared to copper cable, fiber optic cable is immune to the electrical resistance and electromagnetic interference (EMI) which affect signals carried over copper cable. It can support higher data rates. But the problem is that the signal strength over fiber cable is easily to be damaged by the dirt, dust or other material defects in the fiber cable. So fiber optic testing is a must for high performance of the entire network. And much more cares and special tools are needed during fiber optic cable installation.

Connector

Nearly all Fibre Channel switches requires SFP transceiver modules. It’s very common to see 2G and 4G Fibre Channel SFP transceivers in the fiber optics market. For 2G and 4G FC SFPs, the interface is designed as “LC duplex”. When plug in LC patch cords, you should better avoid touching the end face of the connector to ensure the network work with long-term, consistent performance and reliability. If the cable is not preterminated, it will be more complex. You need to strip cable’s outer jacket and the fiber coating to attach the connector. All fiber optic connectors should be carefully tested after installation. If it’s possible, try to buy high quality and certified preterminated cables from reliable vendors.

Conclusion

Fibre Channel is a flexible, scalable, high-speed data transfer interface that can operate over both copper and fiber optical cable. FS.COM provides 2G and 4G Fibre Channel SFP transceivers which can support distance up to 80 km. All the transceivers have been fully tested. We also offer preterminated duplex LC patch cords for Fibre Channel deployment. For more detailed information, please contact via sales@fs.com.

Originally published at www.fiber-optic-equipment.com