Category Archives: Fiber Optical Transceivers

An Analysis On Optical Module Market

An optical module is a single, packaged form factor that works as a transmitter and receiver. An optical transceiver is used in an optical network to convert electrical signals to optical signals and vice versa. Optical modules are widely deployed in optical networking for broadband. While optical module market is driven by the use of broadband in every field. Global adoption of the Internet is driving rapid growth of the data center and the need for very high speed network transmission. Optical transceivers are given full play to upgrade telecommunications networks and launch very large data centers. What’s the future of optical module market? Will it still thrive? You may get a clue in this article.

optical module

Next year is going to be huge for 100GbE

According to IHS Infonetics (NYSE: IHS), the long-awaited ramping up of 100 Gigabit Ethernet (100GbE) optical modules in data center applications may finally be forthcoming. Sales of 40G and 10G optical modules still remain the mainstream in the interim, uncovered by the market research firm in its biannual “10G/40G/100G Data Center Optics” report. As the figure shown below, higher bandwidth and server virtualization calls for higher data rate. The market for 100G data center optics is accelerating, but it has yet to be challenged by widespread data center deployment in the way 40G QSFP optics have. This will change dramatically in the next few year as cheap 100G silicon reaches production and QSFP28 shipments surge as a result,” Schmitt said. “Next year is going to be huge for 100GbE.”

Server Virtualization Drives Higher Data Rates

Server Virtualization Drives Higher Data Rates. Source: Dell’Oro. 07/ 2012

The global optical module market increased from from $3.2 billion in 2013 up to $4.6 billion in 2015, and this dramatic increase is anticipated to grow to $41.1 billion by 2022 driven by the availability and cost effectiveness of 100G, and 400G modules. Next generation optical transceiver devices use less power, are less expensive, and are smarter and smaller. The adoption of widespread use of the 100 Gbps devices, followed by 400 Gbps devices and the vast increases in Internet traffic are vital to helping manage change in the communications infrastructure markets.

Global Industry Analysis

Geographically, North America is seen as the most active optical module market due to rising demand for communication network. In addition, the rising deployment of 100G optical modules for high speed networks is another factor contributing to high demand for optical transceivers. Europe seconds North America in terms of demand for optical transceivers. Moreover, the combined use of 40G and 100G modules in Europe and North America is expected to show steady growth in demand for optical modules in near future. In Asia-Pacific, China is expected to be the fastest growing market for fiber optic transceivers owing to its increasing demand for deployment of 100G equipment.
In North America, JDS Uniphase Corporation, Oclaro Inc., Finisar Corporation, Cisco Systems, Alcatel-Lucent and others are the main manufacturers of optical modules. In Asia-Pacific, Avago Technologies, Wuhan Telecommunications Devices Co. Ltd and FS.COM are some of the leading manufacturers of optical transceivers.

Last But Not Least

Optical modules are deployed to update the communication networks and data center networks for efficient traffic management with higher speeds. Optical networks are the backbone for mobile communication network. With growing demand for reliable and high speed mobile communication, optical transceivers are increasingly being used for the communication network infrastructure and be bound to thrive in optical network. There are numerous optical transceiver modules available in the market differing in the type of data transmission speed, connections and packing forms. Some of the types of optical transceivers available in the market include SFP module, SFP+, X2, XFP, Xenpak, GBIC and others. Furthermore, as per the type of connection, there are single mode (SM), multi-mode (MM) and Wavelength Division Multiplexing (WDM) modules. If you need any of the above type, feel free to contact via sales@fs.com.

A Glance At Cisco Single Mode SFP Specification

SFP(small form-factor pluggable) transceivers compact, hot-pluggable transceiver used for bothtelecommunication and data communications applications. They are an interface with a motherboard, router, switch or optical media converter. Link connection into a fiber optic or copper cabling. SFP transceivers are designed to support SONNET, Fiber Channel, Gigabit Ethernet or similar standards. There are both multi-mode and single mode SFP transceiver types. There are also many vendors manufacturing SFP transceivers like major brand Cisco. Cisco SFP transceivers also have Cisco multi-mode SFP and Cisco single mode SFP transceiver types. The following text will mainly focus on Cisco single mode SFP.

cisco singlemode sfp

An Outline of Cisco SFP Transceiver

The industry-standard Cisco SFP transceivers are mainly used to link equipment in telecommunication and data communications like switches and routers. They support applications like 2G/4G Fiber Channel, SONET/SDH Network, Gigabit Ethernet, High-speed computer links, and with CWDM and DWDM interfaces. Cisco SFP have many types, such as 1000BASE-T, 1000BASE-SX, 1000BASE-LX/LH, 1000BASE-EX, 1000BASE-ZX, or 1000BASE-BX10-D/U on a port-by-port basis. Among them, 1000BASE-T SFP operates on standard Cat 5 UTP copper cabling of link lengths up to 100 m; 1000BASE-SX SFP only operates on multimode fibers; 1000BASE-LX/LH SFP operates on standard single-mode fiber-optic link spans of up to 10 km and up to 550 m on any multimode fibers; 1000BASE-EX SFP only operates on long reach standard single-mode fibers; 1000BASE-ZX SFP operates on long-reach standard single-mode fibers; 1000BASE-BX10-D and 1000BASE-BX10-U SFP operate on a single strand of standard SMF. So we can see that Cisco single mode SFP consists of 1000BASE-EX SFP, 1000BASE-ZX SFP, 1000BASE-BX10-D and 1000BASE-BX10-U SFP.

cisco sfp

A Sketch of Cisco Single Mode SFP Transceiver

Cisco single mode SFP has much tighter tolerances for optics used. The core is smaller and the laser wavelength is narrower. This means that SMF has the capability for higher bandwidth and much longer distances in transmission. Cisco single mode SFP (SMF SFP) work mainly in 1310nm and 1550nm wavelength and is mostly used in long distances transmission environment reaching 2km, 10km, 40km, 60km, 80km and 120km. The color coded bale clasp and color arrow on label are generally blue, yellow or purple. And the color of compatible fiber optic patch cord is yellow.

Cisco Single Mode SFP Specification

Here is a specification chart of Cisco single mode SFP transceivers.

Model Number Transceiver Description
GLC-ZX-SM= 1000BASE-ZX SFP transceiver module for SMF, 1550-nm wavelength, dual LC/PC connector
GLC-BX-D= 1000BASE-BX10 SFP module for single-strand SMF, 1490-nm TX/1310-nm RX wavelength, single LC/PC connector
GLC-BX-U= 1000BASE-BX10 SFP module for single-strand SMF, 1310-nm TX/1490-nm RX wavelength, single LC/PC connector
GLC-BX40-D-I 1000BASE-BX10 SFP module for single-strand SMF, 1550-nm TX/1310-nm RX wavelength, single LC/PC connector
GLC-BX40-U-I 1000BASE-BX10 SFP module for single-strand SMF, 1310-nm TX/1550-nm RX wavelength, single LC/PC connector
GLC-BX80-D-I 1000BASE-BX10 SFP module for single-strand SMF, 1570-nm TX/1490-nm RX wavelength, single LC/PC connector
GLC-BX80-U-I 1000BASE-BX10 SFP module for single-strand SMF, 1490-nm TX/1570-nm RX wavelength, single LC/PC connector
GLC-BX40-DA-I 1000BASE-BX10 SFP module for single-strand SMF, 1490-nm TX/1310-nm RX wavelength, single LC/PC connector
GLC-2BX-D= Dual-channel 1000BASE-BX10 SFP module for single-strand SMF, 1490-nm TX/1310-nm RX wavelength, two single LC/PC connectors
GLC-EX-SMD= 1000BASE-EX SFP transceiver module for SMF, 1310-nm wavelength, extended operating temperature range and DOM support, dual LC/PC connector
SFP-GE-Z= 1000BASE-ZX SFP transceiver module for SMF, 1550-nm wavelength, extended operating temperature range and DOM support, dual LC/PC connector
GLC-ZX-SM-RGD 1000BASE-ZX SFP transceiver module for SMF, 1550-nm wavelength, industrial Ethernet, dual LC/PC connector
GLC-ZX-SMD= 1000BASE-ZX SFP transceiver module for SMF, 1550-nm wavelength, dual LC/PC connector

Conclusion

From the above introduction, you must have a well understanding about Cisco single mode SFP. When choosing SFP modules, you should consider whether it matches the switch port and the cable you have prepared. If you have multimode cable, then you can choose 1000BASE-SX or 1000BASE-LX/LH SFP. If you use single-mode fiber cable, you should select what I’ve mentioned above. While if your cable is copper category, you have to use 1000BASE-T SFP such as GLC-T SFP. On condition that your budget doesn’t allow you to buy original brand module, you can buy the third-party optics from FS.COM with Cisco, Avago, HP and other compatible brands. All the optics have gone through test for 100% compatibility.

SFP-10G-SR vs. SFP-10G-SR-S

SFP-10G-SR is a popular 10G SFP+ optical transceiver in terms of quantity used. It is considered as the mainstream form factor of the 2017 market due to its matured technology and reduced price, even although 40G/100G optical modules are on the very top trend for enterprise and data center for the interconnection. But two years ago, Cisco introduced S-class optics such as SFP-10G-SR-S for enterprise and data center applications. For some web searchers, he will be recommended with SFP-10G-SR-S rather than SFP-10G-SR. But they almost share the same characteristics, so SFP-10G-SR vs. SFP-10G-SR-S, why choose one over the other? Hope this post may give some clue.

SFP-10G-SR vs. SFP-10G-SR-S: Similarity

Seemingly and technically, they don’t have much difference. SFP-10G-SR-S shares the same product specification with SFP-10G-SR. SFP-10G-SR is compliant with 10GBASE-SR standard. The Cisco 10GBASE-SR module supports a link length of 26m on standard Fiber Distributed Data Interface (FDDI)-grade multimode fiber, up to 300m link lengths over OM3 and 400m link lengths over OM4 cables.

FS.COM 10G-SFP-SR

Cisco SFP-10G-SR transceiver is hot-swappable input/output device which allows a 10 Gigabit Ethernet port to link with a fiber optic network. Because it is hot-swappable and MSA compliant, the Cisco SFP-10G-SR transceiver can be plugged directly into any Cisco SFP+ based transceiver port, without the need to power down the host network system. This capability makes moves, add-ons and exchanges quick and painless.

SFP-10G-SR vs. SFP-10G-SR-S: Difference

According to Cisco, S-class optics are intended for enterprise and data center 10G and 40G applications This new set of optics does not display several unnecessary features for these applications, bringing about a more attractive price. That explains why SFP-10G-SR-S price is lower than SFP-10G-SR price.

Except the price, there are some other differences. SFP-10G-SR-S optics aren’t TAA certified. However, the non-S-class optics such as SFP-10G-SR are all compliant to TAA. SFP-10G-SR-S optics only have COM (Commercial temperature range: 0~70℃). However, the temperature range of SFP-10G-SR can be EXT (Extended temperature range: -5~85℃), IND (Industrial temperature range: -40~85℃) and Storage temperature range (-40~85℃). In terms of protocols, SFP-10G-SR-S optics use Ethernet only, they cannot use OTN (Optical Transport Network) or WAN-PHY (Wide Area Network Physics). Furthermore, SFP-10G-SR-S optics just have 10G and 40G applications so far which is specified for 10G and 40G enterprise and data center. Thus, if you don’t need any special features like extra tolerance for temperature, S-Class optics can save you a considerable amount of money.

SFP-10G-SR Price Comparison

Since equipment SFP-10G-SR vendors all rely on MSAs when designing their transceivers, every supplier can produce the transceiver modules with the same functions but with different prices. Unless you have a 100% requirement to buy Cisco, there are a lot of 3rd party compatible vendors out there that you can save a lot of money by using. Here is a price list from different vendors for you to choose from.

Vendor Model Brand Price
CDW SFP-10G-SR Cisco $693.99
Router-Switch SFP-10G-SR Cisco $262.00
Monoprice SFP-10G-SR Ironlink $136.75
10Gtek SFP-10G-SR 10Gtek $41.05
FS.COM SFP-10G-SR FS.COM $16.00

Conclusion

Although SFP-10G-SR vs. SFP-10G-SR-S, they share identical specification, there still are some minor difference. In most cases, SFP-10G-SR-S optics are recommended for 10G and 40G applications due to its low cost. both SFP-10G-SR price and SFP-10G-SR-S price is relatively lower according to the above chart, and they also enjoy good quality. If you need any third-party optical modules or fiber optic cables, give FS.COM a shot.

Introduction To 10GBASE-T SFP+ Transceiver From Different Manufacturers

10GBASE-T is an Ethernet specification using a copper twisted pair connection (Cat6a or Cat7) with an effective bandwidth of 10 Gbit/s and a maximum transmission distance of up to 100 meters. Compared with other 10G optical modules, the 10GBASE-T SFP+ copper RJ45 transceiver has stable performance, you can take full advantage of the existing copper cabling. It’s now becoming a hot option for equipment designers and data center professionals in building their network solution. Thus, there are many manufactures providing 10GBASE-T SFP+ transceivers, like HPE 10GBASE-T SFP+ transceiver, Cisco 10GBASE-T SFP and also FS.COM 10GBASE-T SFP+ copper transceiver. This post will introduce the characteristics of 10GBASE-T SFP+ transceiver of different manufactures respectively, and then you can choose what you want according to your budget.

HPE 10GBASE-T SFP+ Transceiver

According to HPE product specification, the HPE 10GBASE-T SFP+ Transceiver can convert a 10 Gb SFP+ port on an Hewlett Packard Enterprise switch to a 10GBase-T connection. It is specifically designed for high speed communication links that require 10 Gigabit Ethernet over Cat 6a/7 cable. This SFP+ transceiver offers 10 Gb/s communication over RJ45 copper cables. Its specification is shown as follows:

Ports 10GbE SFP+ port; Duplex: full only Interface RJ45
Weight 0.04 lb, fully loaded Operating temperature

 

32℉- 158℉(0℃-70℃)
Operating relative humidity 5%-95%, noncondensing Altitude

 

Up to 10,000 ft
Power consumption maximum 2.5W Cable type Cat6a/7 cable
Maximum distance 30 m Fiber type

 

Copper

Cisco 10GBASE-T SFP+ Transceiver

The Cisco 10GBASE-T SFP is hot-swappable input/output device which allows a 10 Gigabit Ethernet port to link with a fiber optic network. Because it is hot-swappable and MSA compliant, the Cisco 10GBASE-T SFP+ copper transceiver can be plugged directly into any Cisco SFP+ based transceiver port, without the need to power down the host network system. This capability makes moves, add-ons and exchanges quick and painless. The specification of 10GBASE-T Cisco copper transceiver is as follows:

Cisco genuine SFP-10G-T-S Form type SFP+
Max data rate 10.3125Gbps Max transmission distance

 

30 m
Interface RJ45 Cable type

 

Cat6a/cat7
DOM support No Operating temperature 32℉- 158℉(0℃-70℃)

FS.COM 10GBASE-T SFP+ Transceiver

The 10GBASE-T copper SFP+ transceiver FS.COM offered can convert a 10GbE SFP+ port on a switch or NIC (network interface card) to a 10GBASE-T RJ45 connection, allowing 10G bandwidth over existing copper infrastructure instead of changing to new fiber network equipment. It supports links up to 30 m over Cat6a/7 cable. Compared with an embedded 10GBASE-T RJ45 port for link distances up to 30 m, this module has been optimized to save more than 0.5 W per port. Its details are shown as follows:

Part number SFP-10G-T Form type SFP+
Data rate 10Gbps, 5Gbps, 2.5Gbps, 1000Mbps Cable distance

 

Up to 100m*
Power consumption 2.5W Interface

 

RJ45
DOM support No Operating temperature 32℉- 158℉(0℃-70℃)
*Note: 30 meters via 10Gbps, 50 meters via 5Gbps and 2.5Gbps, 100 meters via 1000Mbps.

Cisco sfp-10g-t-s compatible 10gbase-t sfp+

Conclusion

According to aforementioned, no matter HPE 10GBASE-T SFP+ transceiver, Cisco 10GBASE-T SFP+ or FS.COM 10GBASE-T SFP+ copper transceiver all share similar characteristics, like maximum power consumption, form type, interface, operating temperature and so on. But there is one thing that must differ, that is price. HPE 10GBASE-T SFP+ transceiver is charged $685.99 on official online store, Cisco Compatible 10 Gigabit RJ45 Copper SFP+ Prolabs transceiver module is about $395 on ebay and 10Gtek charges that for $339.99, while FS.COM 10GBASE-T SFP+ copper transceiver only costs $280, which is much lower.

FS.COM now provides compatible 10GBASE-T copper SFP+ transceivers as a new optional solution for your network architecture. Customized service is available for a specific brand compatible copper SFP+ module to your requirements. The following table gives some copper SFP+ product numbers and descriptions for your reference:

Product ID Description
66612 Generic Compatible 10GBASE-T SFP+ Copper RJ-45 30m Transceiver
66613 Cisco SFP-10G-T-S Compatible 10GBASE-T SFP+ Copper RJ-45 30m Transceiver
66614 Arista Networks SFP-10GE-T Compatible 10GBASE-T SFP+ Copper RJ-45 30m Transceiver
66615 H3C SFP-XG-T Compatible 10GBASE-T SFP+ Copper RJ-45 30m Transceiver
66616 Dell GP-10GSFP-T Compatible 10GBASE-T SFP+ Copper RJ-45 30m Transceiver
66617 Customized Compatibility 10GBASE-T SFP+ Copper RJ-45 30m Transceiver

10GBASE-T SFP+ Copper Transceiver: A New Option For 10GbE Network

10GBASE-T SFP+ transceiver is specifically designed for high speed communication links that require 10 Gigabit Ethernet over copper cable (Cat 6a/7 cable). 10GBASE-T SFP+ copper transceiver is the first SFP+ transceiver that offers 10 Gb/s communication over this type of media. Compared with other 10GbE optical modules, the 10GBASE-T SFP+ copper  transceiver has stable performance, you can take full advantage of the existing copper cabling. The following post will briefly introduce some related information about 10GBASE-T copper SFP+ transceiver.

Basic Introduction to 10GBASE-T SFP+ Copper Transceiver

10GBASE-T SFP+ copper transceiver has high performance, good reliability and is a cost-effective I/O solution for 10G Ethernet and 10G Fibre Channel applications. SFP+ 10GBASE-T copper transceiver is mainly used in Cat 6a or Cat 7 copper cabling system for 10G transmission with a maximum distance up to 100m. In addition, compared with SFP+ DAC, 10GBASE-T copper SFP+ transceiver can save at least 0.5W power consumption, and its port can both support STP (shielded twisted pair) and UTP (unshielded twisted pair). Therefore 10GBASE-T SFP+ transceiver is becoming more and more popular in network switches and servers because of its lower power consumption and pay-as-you-grow flexibility.

10GBASE-T SFP+ Copper Transceiver Vs. SFP+ Optical Transceiver Vs. SFP+ DAC

SFP+ DAC, SFP+ optical transceiver and 10GBASE-T SFP+ copper transceiver are three common components used in 10G connections. The following chart reveals the differences between them.

10GBASE-T SFP+ Copper Transceiver Vs. SFP+ Optical Transceiver Vs. SFP+ DAC

Form the figure, we can see that each option has its advantages, but 10GBASE-T’s compatibility with existing structured cabling devices and existing low-speed devices makes it uniquely suited for widespread deployment. These features, combined with superior cost and achievable features, make the simplest path of 10GBase migrate from Gigabit Ethernet to 10G Ethernet. What’s more, the 10GBASE-T SFP+ transceiver module has been optimized to save at least 0.5W per port compared to an embedded 10GBASE-T RJ45 port for link distances up to 30m. Thus, the power savings and corresponding operating cost reduction can be substantial.

Features & Advantages of 10GBASE-T SFP+ Copper Transceiver

  • Cost effective at up to 30m distance on UTP cables
  • Extension of the life of any switch hardware, without having to change existing infrastructure
  • Architecture Flexibility: Supports Top of Rack, Middle of Row or End of Row architectures
  • Auto-negotiable backward-compatibility with previous-generation BASE-T networks for a seamless migration to 10GbE
  • Field twisted pair cabling with familiar RJ-45 connector
  • Support for multi-gigabit data rates up to 10 Gbps

10g sfp+ copper rj45 port

Conclusion

As 10GBASE-T network equipment becomes increasingly available, data center decision makers will want to take advantage of the cost savings, convenience, and flexibility provided by deploying 10 Gb/s technology over balanced twisted-pair copper cabling. Nowadays SFP+ 10GBASE-T transceiver, owing to the compatible issue with switches, is not offered by many vendors. However, from a network equipment designer’s perspective, 10G SFP+ copper modules will become popular in the near future. FS.COM has released 10GBASE-T SFP+ copper modules that are tested compatible with major brands like Cisco, Juniper, Dell, Brocade, Arista.

How to Solve the Problems When Using SFP Optical Transceiver

The small form-factor pluggable (SFP) optical transceiver is one of the protagonists of modern networking, which is a hot-swappable, compact media connector used for telecommunication and data communications. It is designed to provide instant fiber connectivity for your networking devices, such as routers and switches. It is a cost-effective way to connect a single network device to a wide variety of fiber cable for different distances and fiber types, including Ethernet, SONET, single-mode fiber, and multi-mode fiber. Therefore, most people are using SFP optical transceivers for their 1G transmission, especially Cisco SFP transceiver. At the same time, there are many problems when using these SFP optical transceivers. This article may summary the problems that may occur and provide the guided solutions for you, as well as give you some notes for maintaining the quality of SFP optical transceivers.

SFP Transceiver

Problems & Solutions

Some problems may appear when we are using SFP optical transceivers. Now let’s talk about why these problems happen and how to solve these problems. The problems are classified as transmitting failure and receiving failure. The problems and solutions are as follows:

Optical Interface Is Polluted and Damaged

Owing to the pollution and damage of the optical interface, its optical link loss become higher, resulting in the optical link fails.

Solutions
  • Testing the environment of the exposed optical interface, some dust and pollution may enter into the structure.
  • Testing the link ending of optical fibers, because the optical interface may experience second pollution.
  • Testing the interface of the optical connector with pigtail, it may have some improper uses.
  • Testing the quality of fiber optic connectors, you could use the inferior optical fiber connectors.
Damage of ESD(Electro Static Discharge)

Static electricity will absorb dust, which may change impedance line and affect the life and function of the product. The ESD will damage components, which may work in short-term, but their life is still affected.

Solutions
  • Avoiding the dry environment, for which easily produce the ESD.
  • Avoiding the abnormal operation. For example, operating the non-hot-swappable optical modules with electricity; directly touching the pin of optical transceiver modules by hand without ESD protection; there is not anti-static packaging during the transport and storage process.
  • Avoiding non ground-connection or bad ground connection.
  • Improving the ESD immunity of electronic components, because the ESD is inevitable.
Incompatibility

While SFP transceivers are fully-compliant with IEEE 802.3 and the SFP multi-source agreement (MSA), they may not be compatible with some network switch equipment. Because some switch manufacturers program their equipment to accept only their own brand of SFPs.

Solutions

Each SFP module holds its own memory in Electrically Erasable Programmable Read – Only Memory (EEPROM). This memory is coded with unique identifiers. The firmware of the host device will check the memory for the correct information to confirm compatibility. A SFP transceiver will work in any host device as long as it has the correct coding. Advance transceivers are coded specifically to suit each host device to avoid this problem.

Notes for Maintaining the Quality of SFP Transceiver

Quality is also very important for SFP optical transceiver, for which is the top priority of customers. Here are some notes:

  • Finding the failure product in advance before shipment
  • Prohibiting the faulty module to leave the factory
  • Decreasing reject rate
  • Guaranteeing the working stability of the products after leaving the factory
Summary

SFP optical transceivers provide a cost-effective and flexible solution for network designs. I hope this article can help you solve the problems when you are using the products and learn how to avoid these problems.

Will Single-mode Fiber Work Over Multimode SFP Transceiver?

Network installers usually come across a situation that device you have in your network does not always fit and work perfectly with the fiber. They plan to make a cable plant based on the multimode cabling, but owing to the link limitation or other reasons, they have to connect multimode equipment with single-mode devices. Is it feasible? Or put it more specifically, can I use the multimode SFP over single-mode fibers or vice versa? This article will give you a detailed illustration about the feasibility of the solutions, and introduce two relevant devices (mode conditioning cable and multimode to single-mode fiber media converter).

Single-mode Fiber Over Multimode SFP—You Can If You Are Lucky

This is the question that has been asked so many time, but no one can give the exact answer—yes or no. Hence, let’s illustrate it in details.

Most people think single-mode and multimode fibers are not interchangable because of the wave length of the laser and core size of the fiber. Single-mode fiber (MMF) uses a laser as a light source (the light beam is very concentrated), while multimode fiber (MMF) uses an LED to generate the signal. This would require two significantly different devices to generate the signal.

The core sizes are drastically different between SMF and MMF. SMF is 9 micron and multimode is 62.5 or 50 micron. If users try to mix the single-mode and multimode cabling in the same network, they might have trouble dealing with the two different types of signal.

However, it is possible to interconnect two devices using SMF interfaces at one end and MMF receiver at the other end. Keep in mind that it depends on the devices, so you can if you are lucky. When plugging LC single-mode duplex fibers on the multimode fiber transceiver (1000GBASE-SX) in the network, you will find the link came up (the light on the switch turns green). Therefore, the multimode fiber transceiver connected by the single-mode fibers works for short-reach application. The following image is the real screenshot of the single-mode fibers inserting into the 1000BASE-SX SFP.

real screenshot of inserting single-mode fiber over multimode fiber transceivers

While it should be stressed that the link is not reliable and it only works for particular brand devices with a very short link length. Many sophisticated vendors like Huawei, Alcatel or Cisco do not support it. Nevertheless, owing to the differential mode delay (DMD) effect, signal loss of this connection is not acceptable, either.

To sum up, this might be feasible but not advisable. If you need to make a connection between single-mode and multimode interfaces, you’d better use the intermediate switch that is able to convert the signals between single-mode and multimode fibers. The following part will introduce two solutions that might be helpful for the multimode and single-mode conversion.

Solution 1: MCP Cable—Single-mode In and Multimode Out

As to the multimode fiber with single-mode SFPs, most people mention the mode conditioning patch (MCP) cables. The MCP cable is launched to support 1000BASE-LX optics over multimode cable plant. The mode conditioning cables allow customers to successfully run Gigabit Ethernet over our multimode cable using single-mode fiber transceivers, Cisco 1000BASE-LX/LH SFP is the special type of transceiver that can both support single-mode and multimode fibers. The image below displays the difference between standard SC multimode patch cable and SC mode conditioning patch cable.

comparison between standard SC multimode fiber patch cable and SC MCP cable

Then, in this situation, you can run successfully from a single-mode fiber transceiver over multimode fiber with the use of MCP cables, but the distance will not exceed the link specification for multimode transceivers. Otherwise, there will be much signal loss in the cable run.

In general, if you want to run multimode fiber optic cable over 1000BASE-LX SFPs, you can use the mode conditioning cable. However, mode conditioning patch cords are required for link distances greater than 984 feet (300 meters). For distance less than 300 m, please omit the mode conditioning patch cords (although there is no problem using it on short links).

Solution 2: Fiber to Fiber Media Converter—Conversion Between Multimode and Single-mode Fibers

As noted before, mode conditioning cables, to some extent, can realize the connection between single-mode to multimode, but you can not say that you can convert single-mode to multimode or vice versa. Mode conversion between multimode and single-mode fibers often requires fiber to fiber media converters or the single-mode to multimode fiber converter.

F2F-10G-Multimode-to-Single-mode

In the above diagram, two Ethernet switches equipped with multimode fiber ports are connected utilizing a pair of fiber-to-fiber converters which convert the multimode fiber to single-mode and enable network connectivity across the distance between Gigabit switches.

Conclusion

It doesn’t really make much sense to use the single-mode fiber transceivers with multimode fibers in your network or vice versa, although the link will come up. Like I said above, you can if you are lucky connect. MCP cables and fiber to fiber converter are the two available options for single-mode and multimode connection. If you bought the wrong fiber optic cables, just replace it into the right one. Fiber optic cables and optical transceivers modules nowadays are very cheap. You won’t need to risk of mixing them in the same network.

Original Source : Single-mode Fiber Work Over Multimode SFP Transceiver

QSFP+ to SFP+ Adapter (QSA) Module Vs. QSFP+ to SFP+ Breakout Cable

People frequently ask about feasible solutions between 10G and 40G servers. QSFP+ breakout cables like QSFP+ to 4 SFP+ cables and MTP to 4 LC harness cables are the commonly used equipment to connect between QSFP+ ports and SFP+ ports. But recently, Cisco launched a new type of product—QSFP+ to SFP+ Adapter (QSA) module that could provide a smooth migration to 40 Gigabit Ethernet. Is it a better solution for the 10G to 40G migration? Should I use the QSA module or 40G QSFP+ breakout cable? This article will answer the above questions and provide some suggestions to you.

QSA Module—Is It a Better Solution for the 40G Migration?

The QSFP+ to SFP+ Adapter module, specified by Cisco, is the module built in QSFP+ form factor with a receptacle for SFP+ cable connector at the back (seen in the below image). When connecting the QSFP port to an SFP+ port, QSA module usually acts as an interface for SFP+/SFP cables. That means you can effectively plug in an SFP+/SFP optics operating at a 10 Gbps port on this module, then inserting the module into a QSFP port cage to realize the 40G Ethernet transition. QSFP+ to SFP+ adapter module ensures the smooth connectivity between 40 Gigabit Ethernet adapter and 10 Gigabit hardware using SFP+ based cabling. Therefore, once the QSA module came out in 2016, it was soon considered as the effective solutions for converting 40G ports to the 10G ports.

Cisco QSFP+ to SFP+ adapter cable

40G QSFP+ Breakout Cables Overview

People usually use either the QSFP+ to 4 SFP+ breakout cables or MTP to LC harness cables to convert the downlink 40G port of ToR (Top of Rack) access layer switch into 4x10G fan out mode, then connect to the 10G cabinet server port. QSFP+ to SFP+ breakout cable including the direct attach copper cable (DAC) and active optical cable (AOC) consists of a QSFP+ connector on one end and four SFP+ connectors on the other end. The cables use high-performance integrated duplex serial data links for bidirectional communication on four links simultaneously.

QSFP+ to SFP+ breakout cable

While the MTP to LC harness cable have one one MTP cables on the one end and four LC connectors on the other end. This type of cable is recommended to be used in the same rack within the short distance. The picture above shows the direct connectivity between the QSFP+ transceivers and SFP+ transceivers by using the MTP to LC harness cable.

QSA Module or QSFP+ Breakout Cable

In this part, I will make a comparison between QSFP+ to SFP+ adapter modules and QSFP+ breakout cables from the aspects of cost, performance and compatibility.

Cost—QSFP+ Breakout Cables Wins

QSFP+ to SFP+ adapter module is not certificated by Multi-source Agreement (MSA), but a sole source paradigm defined by few vendors. The only vendor owns its patent, so the QSA modules on the market are quite expensive. Nevertheless, QSFP+ breakout cables covered in the MSA standard, support both copper and optical connectivity, which are much cheaper than QSA modules. Cost comparison between QSA module and QSFP+ breakout cable (DAC, 1m) is listed in the below table.

cost comparison between QSA module and QSFP+ breakout cable

Performance

With QSA module, users have the flexibility to use any SFP+/SFP optics to connect to the 40Gbps data rate with a single 10G connection. However, QSA module only exists in 10G-40G speed, which also explains the reasons of its unpopularity of the market. QSFP+ to 4 SFP+ breakout cables split the 40G channel into 4x10G channel which provide four times more data transfers than QSA module does.

Compatible Switch and SFP/SFP+ Modules

QSA modules, according to Cisco, are available in 40 Gigabit Ethernet compatibility matrix. Cisco SFP/SFP+ transceivers that can be plugged into the QSA modules are concluded as Cisco 10GBASE-SR, LR, ER, ZR, DWDM SFP+, FET-10G and 10G SFP+ cable as well as SFP (1000BASE-T, SX, LX, EX, ZX). As for the QSFP+ to SFP+ breakout cables, different vendors have different compatible issues. Keep in mind that you should find the reliable fiber optic transceiver manufacturers.

Reminder:

  • Before using the QSA modules or the QSFP+ breakout cables to connect a 40 Gigabit Ethernet port to a 10 Gigabit SFP+ port, you must enable the fan-out mode of your devices.
  • Not all the 40G cards and switches can be split into 4x 10Gb mode, for example, the Mellanox QSFP cards do not support the QSFP to SFP+ breakout, but their switches can.
  • With the QSA module, you can directly use the SFP+ modules in a QSFP+ port, but you cannot use the QSFP+ optical cables in a QSA setup.
  • Telecom industry has been modified rapidly. Hence, it is more cost-effective to make additional investment in high-speed switches instead of breakout cables and expensive QSA modules.
Conclusion

Both the QSFP+ breakout cables and QSA modules provide a smooth migration to the 40 Gigabit Ethernet. With these optics, you can reuse the existing 10G SFP+ cables, optical transceivers and switches when upgrading to 40G Ethernet. QSFP+ breakout cables is regarded as the cost-effective and reliable solutions for the most situations, but QSA module is preferable for the application with a single 10G connection.

Can I Use the QSFP+ Optics on QSFP28 Port?

100G Ethernet will have a larger share of network equipment market in 2017, according to Infonetics Research. But we can’t neglect the fact that 100G technology and relevant optics are still under development. Users who plan to layout 100G network for long-hual infrastructures usually met some problems. For example, currently, the qsfp28 optics on the market can only support up to 10 km (QSFP28 100GBASE-LR4) with WDM technology, which means you have to buy the extra expensive WDM devices. For applications beyond 10km, QSFP28 optical transceivers cannot reach it. Therefore, users have to use 40G QSFP+ optics on 100G switches. But here comes a problem, can I use the QSFP+ optics on the QSFP28 port of the 100G switch? If this is okay, can I use the QSFP28 modules on the QSFP+ port? This article discusses the feasibility of this solution and provides a foundational guidance of how to configure the 100G switches.

For Most Switches, QSFP+ Can Be Used on QSFP28 Port

As we all know that QSFP28 transceivers have the same form factor as the QSFP optical transceiver. The former has just 4 electrical lanes that can be used as a 4x10GbE, 4x25GbE, while the latter supports 40G ( 4x10G). So from all of this information, a QSFP28 module breaks out into either 4x25G or 4x10G lanes, which depends on the transceiver used. This is the same case with the SFP28 transceivers that accept SFP+ transceivers and run at the lower 10G speed.

QSFP+ can work on the QSFP28 ports

A 100G QSFP28 port can generally take either a QSFP+ or QSFP28 optics. If the QSFP28 optics support 25G lanes, then it can operate 4x25G breakout, 2x50G breakout or 1x100G (no breakout). The QSFP+ optic supports 10G lanes, so it can run 4x10GE or 1x40GE. If you use the QSFP transceivers in QSFP28 port, keep in mind that you have both single-mode and multimode (SR/LR) optical transceivers and twinax/AOC options that are available.

In all Cases, QSFP28 Optics Cannot Be Used on QSFP+ Port

SFP+ can’t auto-negotiate to support SFP module, similarly QSFP28 modules can not be used on the QSFP port, either. There is the rule about mixing optical transceivers with different speed—it basically comes down to the optic and the port, vice versa. Both ends of the two modules have to match and form factor needs to match as well. Additionally, port speed needs to be equal or greater than the optic used.

How to Configure 100G Switch

For those who are not familiar with how to do the port configuration, you can have a look at the following part.

  • How do you change 100G QSFP ports to support QSFP+ 40GbE transceivers?

Configure the desired speed as 40G:
(config)# interface Ethernet1/1
(config-if-Et1/1)# speed forced 40gfull

  • How do you change 100G QSFP ports to support 4x10GbE mode using a QSFP+ transceiver?

Configure the desired speed as 10G:
(config)# interface Ethernet1/1 – 4
(config-if-Et1/1-4)# speed forced 10000full

  • How do you change 100G QSFP ports from 100GbE mode to 4x25G mode?

Configure the desired speed as 25G:
(config)# interface Ethernet1/1 – 4
(config-if-Et1/1-4)# speed forced 25gfull

  • How do you change 100G QSFP ports back to the default mode?

Configure the port to default mode:
(config)# interface Ethernet1/1-4
(config-if-Et1/1)# no speed

Note that if you have no experience in port configuration, it is advisable for you to consult your switch vendor in advance.

Conclusion

To sum up, QSFP+ modules can be used on the QSFP28 ports, but QSFP28 transceivers cannot transmit 100Gbps on the QSFP+ port. When using the QSFP optics on the QSFP28 port, don’t forget to configure your switch (follow the above instructions). To make sure the smooth network transmission, you need to ensure the connectors on both ends are the same and no manufacturer compatibility issue exists.

100G QSFP28 PSM4 to Address 500m Links in Data Center

100G QSFP28 PSM4 optics is a type of 100G optical transceiver that provides a low-cost solution to long-reach data center optical interconnects. 100G PSM4 (parallel single-mode 4 lane) standard is mainly targeted to data centers that based on a parallel single-mode infrastructure for a link length of 500 m. Compared with the hot-selling 100GBASE-SR4 and 100GBASE-LR4 optics, 100G QSFP28 PSM4 recently wins the popularity among the overall users. This article will provide a complete specification of the 100G QSFP28 PSM4 transceiver and explain the reason why people would need QSFP28 PSM4.

QSFP28 module

QSFP28 PSM4—A Low-Cost but Long-Reach Solution

100G QSFP28 PSM4 is compliant with 100G PSM4 MSA standard, which defines a point-to-point 100 Gb/s link over eight parallel single-mode fibers (4 transmit and 4 receive) up to at least 500 m. PSM4 uses four identical lanes per direction. Each lane carries a 25G optical transmission. The 100G PSM4 standard is now available in QSFP28 and CFP4 form factor. Table 2 shows the diagram of the 100G QSFP28 PSM4 Specification. 100G PSM4 is a low-cost solution. Its cost structure is driven by the cost of the fiber and the high component count. FS.COM offers the Cisco compatible 100G QSFP28 PSM4 at US$750.00.

diagram of QSFP28 PSM4

As you can see in the above image, 100G QSFP28 PSM4 transceiver uses four parallel fibers (lanes) operating in each direction, with transmission distance up to 500 meters. The source of the QSFP28 PSM4 module is a single uncooled distributed feedback (DFB) laser operating at 1310 nm. It needs either a directly modulated DFB laser (DML) or an external modulator for each fiber. The 100GBASE-PSM4 transceiver usually needs the single-mode ribbon cable with an MTP/MPO connector.

Why Do We Need 100G QSFP28 PSM4?

100G PSM4 is the 100G standard that has been launched by multi-source agreement (MSA) to enable 500m links in data center optical interconnects. But as we all know, there are several popular 100G interfaces out there on the market, such as QSFP28 100GBASE-SR4, QSFP28 100GBASE-LR4, QSFP28 100GBASE-CWDM4, and CFP 100GBASE-LR4, etc. So with so many options, why do we still need 100G QSFP28 PSM4?

To better help you make up your mind, you need to figure out the following questions:

Q1: What are the net link budget differences between PSM4, SR4, LR4 and CWDM?
Table 3 displays the detailed information about these 100G standards.

100GBASE-PSM4 100GBASE-CWDM4 100GBASE-SR4 100GBASE-LR4
4-wavelength CWDM multiplexer and demultiplexer No need Need No need Need
Connector MPO/MTP connector Two LC connectors MPO/MTP connector Two LC connectors
Reach 500 m 2 km 100 m 10 km

Note: the above diagram excludes the actual loss of each link (it is the ideal situation). In fact, WDM solution are at least 7 db worse link budget than PSM4. For a 2 km connectivity, a CWDM module will have to overcome about 10 db additional losses compared to PSM4. And the 100G LR4 optics at 10 km is 12 db higher total loss than PSM4.

Q2: What power targets are achievable for each, and by extension what form factors?
According to the IEEE data sheet, the WDM solutions cannot reasonably fit inside QSFP thermal envelop, while PSM4 can fit inside the QSFP thermal envelope. That means you would need the extra power for the WDM solution of your network. But if you use the QSFP PSM4, this won’t be a problem.

All in all, a 100G QSFP28 PSM4 transceiver with 500m max reach is a optional choice for customers. Because other 100G optics are either too short for practical application in data center or too long and costly. QSFP28 PSM4 modules are much less expensive than the 10 km, 100GBASE-LR4 module, and support longer distance than 100GBASE-SR4 QSFP28.

Summary

QSFP28 PSM4 is the lowest cost solution at under one forth the cost of either WDM alternatives. 100G QSFP28 PSM4 can support a link length of 500 m, which is sufficient for data center interconnect applications. 100G QSFP28 PSM4 also offers the simplest architecture, the most streamlined data path, higher reliability, an easy upgrade path to 100G Ethernet.