How to Save Cost for 500Gbps Metro Network Over Long Distance?

Increasing bandwidth has always been the most important task of telecom engineers. Through decades of research and engineering effort, 40Gbps and 100Gbps solutions have been used for network applications. But 40G and 100G transceivers can’t support too much long distance (QSFP-40G-ER4 for 40 km, QSFP-100G-LR4 for 10 km). How to extend the 500Gbps link to thousands of kilometers in Metro network within limited budget?

Save Fiber Cost–500Gbps Over Single Fiber Cable

Fiber cable cost takes a certain percentage in the whole network budget. Point to point connection needs many cables, while WDM technology take well care of this issue. In a metro network, usually multiple 10Gbps signals are transmitted by the use of DWDM Mux/Demux over a single fiber cable, which can save lots of money on multiple fiber cables and cable management issues. Then how to save cost to transmit 500Gbps signals over single fiber cable?

It sounds unbelievable. But we have the cost-effective solution. As we know, it will cost too much to replace all the current network system for upgrading to higher data rate. To save cost for increasing bandwidth, some producers add an extra port on DWDM Mux/Demux and that is 1310nm or 1550nm port. This port supports 1310nm or 1550nm transceiver. With such port, you can add 1G/10G/40G/100G to the existing DWDM network. For instance, we use 40-channel C21-C60 dual fiber DWDM Mux/Demux with 1310nm port and 1310nm band port for 1G/10G/40G/100G “grey” light. Plug 10G DWDM SFP+ transceivers into 40 channels, the overload is 400Gbps. Once plugging a 1310 40G QSFP+ LR4/ER4, then the total link reach up to 440G (400G + 40G). If install a 100G QSFP28 LR4 transceiver into 1310 port, the whole transport will be 500Gbps (400G + 100G). See this solution realize the goal of saving cost to run such huge network load over a single fiber.

Extend 500G Transmission Distance

Since 500G signals can be transmitted over a single fiber cable, we have another issue to be solved. 500G transmission distance is needed far more than few kilometers in real life, maybe thousand of kilometers. How to extend the transmission distance?

According to IEEE standard, LR4 and ER4 transceivers can support the reach of 10 km and 40 km in the in ideal conditions, not considering fiber loss or connector loss. To extend 500Gpbs transmission distance, we need SOA (Semiconductor Optical Amplifier) and EDFA (Erbium Doped Fiber Amplifier). Add an SOA to support 40G/100GBASE-LR4 transceiver (over 1310 nm). The SOA is used to amplify incoming (Rx) signal on the receiving side of the link. So that the distances can reach up to 60 km. In 10Gbps DWDM networks, the signal transmission distance can be extended to hundreds of kilometers by the use of and EDFA (Erbium Doped Fiber Amplifier).

Recommended DWDM Solutions for 500Gbps Metro Network

ID#	FS Part Number	Description
35887	40MDD-1RU-A1-FSDWDM	40 Ch 1RU Duplex DWDM MUX DEMUX C21 to C60 with 1310nm Port and Monitor Port
14491	DWDM-SFP10G-40	10GBASE 100GHz DWDM SFP+ 40km, LC Duplex Interface, C21 to C60
31533	DWDM-SFP10G-80	10GBASE 100GHz DWDM SFP+ 80km, LC Duplex Interface, C21 to C60
14599	DWDM-XFP10G-40	10GBASE 100GHz DWDM XFP 40km, LC Duplex Interface, C21 to C60
14650	DWDM-XFP10G-80	10GBASE 100GHz DWDM XFP 80km, LC Duplex Interface, C21 to C60
35208	QSFP-LR4-40G	40G QSFP+ LR4 1310nm 10km, LC Duplex Interface
35210	QSFP-ER4-40G	40G QSFP+ ER4 1310nm 40km, LC Duplex Interface
35014	CFP2-LR4-100G	100G CFP2 LR4 1310nm 10km, LC Duplex Interface
35192	FS-SOA-G10	10dB Gain 1310nm Semiconductor Optical Amplifier
31366	EDFA-BAO22	20dBm Output C-band 40 Channels 26dB Gain Booster EDFA

Summary

DWDM technology is very necessary to extend Metro Network reach. In this 500Gpbs Metro network, I have introduced very detailed cost-effective solutions. Remember all the indispensable DWDM equipment such as DWDM transceivers, DWDM Mux/Demux, EDFA, etc. For more information, please visit the site about FS.COM Long Haul DWDM Network Solution.

Related articles: How to Extend 40G Connection up to 80 km?
Economically Increase Network Capacity With CWDM Mux/DeMux

Originally published at http://www.fiber-optic-equipment.com

Which 40G QSFP+ Transceivers Can Be Used for 4x10G?

Since the overwhelming growth in data traffic, many data centers are loaded with 10G and 40G based Ethernet switches for 10G to 40G migration. 40G switches allow the configuration of 40G port to act as one port or break out into four individual ports. To get easy 10G/40G migration, we should better select 40G QSFP+ transceivers which can break out as 4x10G connectivity. Among so many versions of 40G QSFP+ transceivers including QSFP-40G-SR4, QSFP-40-CSR4, QSFP-40G-LR4, QSFP-40G-ER4, etc., which 40G QSFP+ transceiver can be used for 4x10G?

QSFP-40G-SR4/CSR4 for 4x10G

40G short distance multimode transceivers are interfaced with 12-fiber MTP/MPO, such as 40G SR4, CSR4. To know why these 40G QSFP+ modules can be used for 4x10G, let’s see how QSFP-40G-SR4 work? First, 4 electrical input signals of 10G converted into parallel optical signals are sent from the transmitter over 4 parallel fiber strands. Then the parallel optical signals are converted into parallel electrical signals by the use of a photo detector array and transmitted to the receiver over another 4 parallel fiber strands. QSFP-40G-SR4 needs 8 fibers to transmit and receive signals. QSFP-40G-SR4 transceivers are interfaced with 12-fiber MTP/MPO. Therefore, QSFP-40G-SR4 and QSFP-40G-CSR4 transceivers can be easily broken down to 4x10G connections. Each 10G signal lane of QSFP-40G-SR4 is compliant to IEEE 10GBASE-SR specifications. And this 10G/40G connection can be achieved by using an MTP-LC harness cable or MTP cable and MTP-LC breakout patch panel to connect the QSFP-40G-SR4 and four 10GBASE-SR modules.

Can QSFP-40G-LR4/ER4 Be Used for 4x10G?

QSFP-40G-LR4 transceivers apply CWDM (Coarse Wavelength Division Multiplexing) technology. From the transmitter side, 4 input electrical signals of 10G are converted into 4 CWDM optical signals by a driven 4-wavelength distributed feedback (DFB) laser array. Then 4 CWDM signals are multiplexed to a singlemode fiber for 40G optical signal transmission. On the receiver side, the receiver accepts 40G CWDM optical signals input and demultiplexes them into 4 individual 10G optical data streams with different wavelengths. Multiplexing and demultiplexing of the four wavelengths are managed in the device. The 40 Gigabit Ethernet signal is carried over four wavelengths on a pair of singlemode fibers. The duplex fibers are used for bi-directional transmission. QSFP-40G-LR4 and QSFP-40G-ER4 are interfaced with duplex LC connector. Therefore, we can’t split QSFP-40G-LR4 or QSFP-40G-ER4 to 4 individual duplex SMF fibers to route them to 4 separate 10G transceivers by simple optical rerouting.

But if you insist to split the 40G into four 10G streams using QSFP-40G-LR4 or QSFP-40G-ER4 modules, how to achieve that connection? Then you need a simple multiplexer/demultiplexer which split the four wavelengths on duplex fibers into 4x10G signal in four different fibers. With such equipment, the QSFP-40G-LR4 or QSFP-40G-ER4 outputs can be physically broken down from one duplex fiber into four duplex fibers so that each of the wavelengths is transmitted in four different fibers (As the following figure shows).

How About QSFP-40G-PLRL4?

From the above content, you may get an inclusion that multimode 40G QSFP+ transceivers can be directly used as 4x10G while singlemode 40G QSFP+ transceivers can’t. However, you ignore one singlemode transceiver QSFP-40G-PLRL4. This 40G QSFP+ transceiver connects with 12-fiber MTP/MPO patch cable though it’s designed for long distance transmission. Similar to QSFP-40G-SR4, QSFP-40G-PLRL4 also needs 8 fibers to transmit and receive signals. So you can easily get 10G/40G singlemode connection applying QSFP-40G-PLRL4.

Summary

Some data centers may face the issue of migration from 10G to 40G. Except the switch, you also need to know 40G QSFP+ transceivers well especially what kind of 40G QSFP+ transceivers can be used for 4x10G connectivity. In this article, you can see 40G QSFP+ transceivers with MTP/MPO interface can achieve that connection by simple optical routing. As to 40G QSFP+ transceivers with duplex LC interface, you need spare equipment for multiplexing/demultiplexing. For 40G to 4x10G solutions, you can find your desired one from FS.COM.

Related article: How to Extend 40G Connection up to 80 km?

QSFP+ to 4xSFP+ AOC and QSFP+ MTP Breakout Cable Solution

How to Select Fiber Patch Cable for 40G QSFP+ Modules?

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

How to Extend 40G Connection up to 80 km?

As 40G connectivity is accelerating, many data centers prepare to migrate from 10G to 40G. But the link distance between 10G and 40G switches is a big challenge. This article can help you extend 40G connection distance.

Current 40G QSFP+ Connection—Max 10 km

As we know, 40GBASE-SR4 QSFP+ is designed for short distance of up to 150m connection. 40GBASE-PLR4 QSFP+ can support long distance link of up to 10 km. Both 40G QSFP+ modules are interfaced with 12-fiber MTP/MPO and can break out into 4x10G connection. To build 10G-40G connection, for instance, using singlemode 8-fiber MTP-LC harness cable to connect 40GBASE-PLR4 QSFP+ and 4x10G SFP+ modules. As the direct connection distance between two 40GBASE-PLR4 QSFP+ optics can reach at most 10km, it’s easy to understand that the connection between 10G and 40G may be shorter. However, we provide a method to extend 40G connection to 80km distance. Continue to read this article and find the answer.

Equipment for Extending 40G QSFP+ Connection

To extend 40G QSFP+ connection distance, we have to use WDM transponder OEO (Optical-Electrical-Optical) repeater. OEO repeater allows connection between fiber to fiber Ethernet equipment, serving as fiber mode converter, or as fiber repeater for long distance transmission. It can also function as CWDM/DWDM optical wavelength conversion. Now we will use a multi-service transport system, including a hot-swappable plug-in OEO card which only occupies 1 slot. The other space can be left for holding more cards such as DCM, EDFA, OLP. On the left side, there is a card for centralized network management.

This is a 4-channel multi-rate WDM transponder with an OEO-10G card containing 8 SFP/SFP+ slots and can support up to 11.3G rate. The OEO card can convert 1G~11.3 Gbps Ethernet signals into a corresponding wavelength in CWDM and DWDM network infrastructures. Transmission distance can reach 80 km.

Except WDM transponder OEO repeater, we still need DWDM Mux/Demux and DWDM SFP+ to extend the distance to 80 km. DWDM Mux/Demux is to combine 4x10G signals of different wavelengths on one single fiber so that it’s the best solution to increase network capacity and save cost. Here we use 40-channel C21-C60 dual fiber DWDM Mux/Demux. So we can choose suitable 10G DWDM SFP+ modules 80km transceiver between the wavelengths of C21 and C60.

For your reference, the equipment for 40G connection extension mentioned above are from FS.COM. You can select those of other specifications according to your own needs.

Equipment	Details
Fiber Transceiver	40GBASE-PLR4 QSFP+ 1310nm 10km MTP/MPO Transceiver
	Generic Compatible 10GBASE-LR SFP+ 1310nm 10km DOM Transceiver
	C21-C60 DWDM SFP+ 80km DOM Transceiver
Transponder Repeater	4-channel WDM transponder OEO repeater
DWDM Mux/Demux	40 Channels C21-C60 Dual Fiber DWDM Mux Demux with Monitor Port, 3.0dB Typical IL

Extend 40G QSFP+ Connection to 80 km

Install 40GBASE-PLR4 QSFP+ into QSFP+ port of a switch and 4 10GBASE-LR SFP+ into the Ethernet ports of the WDM transponder OEO repeater. Then plug a singlemode 8-fiber MTP-LC harness cable to connect 40GBASE-PLR4 QSFP+ and 4 SFP+ modules. Because of the OEO repeater function, 4x10G Ethernet signals are converted into corresponding wavelengths in DWDM network infrastructure. Then install 4 x 10G DWDM SFP+ transceivers into other four ports of OEO repeater. Next step is to connect DWDM SFP+ modules on the OEO repeater and DWDM Mux/Demux by using LC duplex patch cables. In this way, 40G QSFP+ distance can be extend up to 80 km.

Conclusion

10 km transmission distance is not the limit of 40G connection. From this article, you can extend 40Q QSFP+ to 80 km by mainly applying WDM transponder OEO repeater, DWDM Mux/Demux and 10G DWDM SFP+. If need to break your network distance limit, please visit our site www.fs.com or contact us via sales@fs.com.

Originally published at: http://www.fiber-optic-equipment.com.

Difference Between QSFP, QSFP+, QSFP28

SFP is short for small form factor. It refers to fiber optic transceivers supporting 1Gbps data rate. Except SFP, current market is full of various types of fiber optic transceivers, such as QSFP, QSFP+ and QSFP28. At the first sight, these transceiver modules are very similar. But actually, they have big differences. To know the difference clearly is good to make the right choice for your network connection. So what are the differences between QSFP,  QSFP+, QSFP28?

QSFP vs QSFP+

“Q” of QSFP means quad (4 channels). QSFP is a compact, hot-pluggable transceiver used for data communications. The QSFP specification supports Ethernet, Fibre Channel, InfiniBand and SONET/SDH standards with different data rate options. QSFP transceivers support the network link over singlemode or multimode fiber patch cable. QSFP modules are commonly available in several different types: 4x1G QSFP, 4x10G QSFP+, 4x28G QSFP28. From this side, QSFP vs QSFP+ vs QSFP28 all share the same small form-factor. literally QSFP uses 4x1G lanes and was only found in some FC/IB contexts.

While QSFP+ transceivers, evolving from 4x1G lanes (QSFP) to 4x10G lanes, are designed to support 40G Ethernet, Serial Attached SCSI, QDR (40G) and FDR (56G) Infiniband, and other communications standards. QSFP+ standard is the SFF-8436 document which specifies a transceiver mechanical form factor with latching mechanism, host-board electrical-edge connector and cage. QSFP+ modules integrates 4 transmit and 4 receive channels plus sideband signals. Then QSFP+ modules can break out into 4x10G lanes. QSFP+ modules are used to connect switches, routers, Host Bus Adapters (HBAs), enterprise data centers, high-performance computing (HPC) and storage. But some may think QSFP as the same with QSFP+, especially in the Ethernet world.

QSFP+ vs QSFP28

QSFP+ and QSFP28 differs in “28” as the name says. QSFP28 is a hot-pluggable transceiver module designed for 100G data rate. QSFP28 integrates 4 transmit and 4 receiver channels. “28” means each lane carries up to 28G data rate. QSFP28 can do 4x25G breakout connection, 2x50G breakout, or 1x100G depending on the transceiver used. While QSFP+ supports the data rate of 40G, 4 channels for transmitting and 4 channels for receiving, each lane carrying 10G. QSFP+ can break out into 4x10G or 1x40G connection.

Usually QSFP28 modules can’t break out into 10G links. But it’s another case to insert a QSFP28 module into a QSFP+ port if switches support. At this situation, a QSFP28 can break out into 4x10G like a QSFP+ transceiver module. One thing to note is that you can’t put a QSFP+ transceiver into a QSFP28 port to avoid destroying your optics.

FS.COM QSFP+ vs QSFP28

Compatible with major brands such as Cisco, Juniper, Arista, Brocade, etc., FS.COM QSFP+ and QSFP28 modules can support both short and long-haul transmission. Here lists our generic QSFP+ and QSFP28 modules in the following table.

FS.COM Generic QSFP+

Model	Description	Price List	In Stock
17931	40GBASE-SR4 QSFP+ 850nm 150m MPO Transceiver for MMF	US$ 49.00	1061 pcs
34917	40GBASE-PLRL4 QSFP+ 1310nm 2km MPO Transceiver for SMF	US$ 220.00	49 pcs
24422	40GBASE-LR4 and OTU3 QSFP+ 1310nm 10km LC Transceiver for SMF	US$  340.00	50 pcs
34912	40GBASE-CSR4 QSFP+ 850nm 400m MPO Transceiver for MMF	US$  70.00	141 pcs
35205	40GBASE-UNIV QSFP+ 1310nm 2km LC Transceiver for SMF&MMF	US$  340.00	18 pcs
34913	40GBASE-LR4L QSFP+ 1310nm 2km LC Transceiver for SMF	US$ 340.00	44 pcs
48721	40GBASE-SR Bi-Directional QSFP Module for Duplex MMF	US$  300.00	106 pcs
35209	40GBASE-PLR4 QSFP+ 1310nm 10km MPO Transceiver for SMF	US$  380.00	34 pcs
35211	40GBASE-ER4 and OTU3 QSFP+ 1310nm 40km LC Transceiver for SMF	US$  1,500.00	40 pcs
39986	40GBASE-LR4 CFP 1310nm 10km SC Transceiver for SMF	US$  800.00	Available

FS.COM Generic QSFP28

Model	Description	Price List	In Stock
35182	Generic Compatible QSFP28 100GBASE-SR4 850nm 100m Transceiver	US$ 270.00	38 pcs in stock
65216	Generic Compatible QSFP28 100GBASE-PSM4 1310nm 500m Transceiver	US$ 750.00	26 pcs in stock
65214	Generic Compatible QSFP28 100GBASE-CWDM4 Lite 1310nm 2km Transceiver	US$ 1,350.00	26 pcs in stock
65215	Generic Compatible QSFP28 100GBASE-CWDM4 1310nm 2km Transceiver	US$ 1,350.00	26 pcs in stock
39025	Generic Compatible QSFP28 100GBASE-LR4 1310nm 10km Transceiver	US$ 2,800.00	Available

Conclusion

The difference between QSFP vs QSFP+ vs QSFP28 has been stated clearly in this article. Though QSFP is thought as QSFP+, when talking about 40G, actually we mean QSFP+. QSFP+ vs QSFP28 mainly differs in data rate and breakout connection. So you must be sure what you need is 40G QSFP+ or 100G QSFP28 for high density applications, especially when connecting with 10G SFP+.

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

Which One to Select, GLC-LH-SM Vs GLC-LH-SMD?

Among so many different Cisco SFP modules, sometimes you may feel confused. Because the differences of some SFP modules are tiny, for instance, Cisco SFP GLC-LH-SM and Cisco SFP GLC-LH-SMD. If you can’t understand the the difference between these two Cisco SFP modules, you don’t know which one to select for your Cisco switch. This article is gonna explain GLC-LH-SM vs GLC-LH-SMD.

Cisco SFP GLC-LH-SM

Cisco SFP GLC-LH-SM is a hot swappable transceiver module that transfers the data rate of 1 Gbps. It’s compliant with IEEE 802.3 1000BASE-LX/LH standard. It supports the link lengths up to 10 km over single mode fiber patch cable at a wavelength of 1310 nm. It can be also applied for short network connection over multimode fiber cable (550 m).
Other features:
Interface: LC duplex
Tx power: -9.5 ~ -3dBm
Receiver Sensitivity < -23dBm
Commercial Temperature Range: 0 to 70°C (32 to 158°F)
DOM Support: No

Cisco SFP GLC-LH-SMD

Cisco SFP GLC-LH-SMD is a hot pluggable transceiver module running the data rate at 1 Gbps. This SFP is interfaced with 1000BASE-LX/LH ports. And it can support both single mode and multimode applications.
Other features:
Interface: LC duplex
Tx power: -9.5 ~ -3dBm
Receiver Sensitivity < -23dBm
Commercial Temperature Range: 0 to 70°C (32 to 158°F)
DOM Support: Yes

GLC-LH-SM vs. GLC-LH-SMD Similarities

Cisco SFP GLC-LH-SM and Cisco SFP GLC-LH-SMD are both used for 1Gbps Ethernet network. They support with IEEE 802.3 1000BASE-LX/LH standard and are compatible with each other. The two Cisco SFP modules can be connected with single mode and multimode LC fiber patch cable. If one switch supports Cisco SFP GLC-LH-SM, then it can also support Cisco SFP GLC-LH-SMD. Here are supported switches for these two Cisco SFP modules: Catalyst Express 500, Catalyst Express 520, Cisco ME 3400, Cisco ME 4900 series, Cisco ME 6500 series, Catalyst 2940 series, Catalyst 2950 series, Catalyst 2960 series, Catalyst 2960 S series, Catalyst 2970 series, Catalyst 3560 series, Catalyst 3560 E series, Catalyst 3560-X series, Catalyst 3750 series, Catalyst 3750-E series, Catalyst 3750-X series, Catalyst 4500series, Catalyst 4900 series, Catalyst 6500 series, cisco IE3010 series.

GLC-LH-SM vs. GLC-LH-SMD Differences

The difference between Cisco SFP GLC-LH-SM and Cisco SFP GLC-LH-SMD is that Cisco SFP GLC-LH-SMD has additional letter “D”. What does “D” mean?

There are two kinds of misunderstanding about “D”. Some think “D” represent “duplex”. Cisco SFP GLC-LH-SMD supports duplex interface. But Cisco SFP GLC-LH-SM should be connected with duplex LC patch cable. And nearly all SFP transceiver modules, except copper SFPs, are interfaced with duplex ports. So this understanding is obvious wrong. Some think that “D” means “ruggged”. This opinion is not true either. “Rugged” is abbreviated to “RGD”, for example, Cisco GLC-LX-SM-RGD Compatible 1000BASE-LX/LH SFP 1310nm 10km DOM Transceiver.

“D” of GLC-LH-SMD transceiver has additional support for Digital Optical Monitoring (DOM) capability. From the features stated above, Cisco SFP GLC-LH-SMD can support DOM function while Cisco SFP GLC-LH-SM can’t. DOM provides a diagnostic monitoring interface for optical transceiver modules. DOM supports monitoring of optic output power, optic input power, temperature, laser bias current, and transceiver voltage. When DOM is enabled, the system monitors the temperature and signal power levels for the optical transceiver modules in the specified ports. Console messages and syslog messages are sent when optical operating conditions fall below or rise above the SFP manufacturer-recommended thresholds.

Which to Select, GLC-LH-SM vs. GLC-LH-SMD?

Cisco SFP GLC-LH-SM and Cisco SFP GLC-LH-SMD are very similar and compatible with each other. The only difference is that the latter one has DOM function. SFP with DOM is better for transceiver and system protection. So you are suggested to select Cisco SFP GLC-LH-SMD. Except these two Cisco SFPS, you can find other Cisco compatible SFPs from FS.COM. For more information, please visit out site http://www.fs.com.

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

Spend Less on Building 100GbE Network With QSFP28 AOC

Currently 10GbE and 40GbE network are efficient and enough for some users. However, to some large-scale data centers, 40GbE Internet speed can’t meet their demands as the Internet continues to grow in size and traffic. According to research predicts, global data center Internet protocol traffic will grow by 31% every year within next five years. So 100GbE technology will become the mainstream in the near future. Cisco, Juniper, Arista provide 100GbE switches, routers and supported QSFP28 transceiver, QSFP28 AOC. But many enterprises still can’t upgrade to 100GbE network since the switch and QSFP28 AOC are quite expensive. Don’t worry about the high cost. This article will help you find a way to spend less on building 100GbE network with QSFP28 AOC.

QSFP28 AOC

100GbE QSFP28 AOC is composed of an OM4 multimode cable connecting two QSFP28 connectors on each end. The form factor design is easy for plugging and removal. The QSFP28 AOC is compliant to the QSFP MSA (multi-source agreement). QSFP28 AOCs support 100G QSFP28 standards and are available in various lengths (usually from 1-30 meters). 100G QSFP28 AOCs provide an affordable low-power alternative to interconnect 100G QSFP28 ports in data center applications. It’s useful for simplified intra rack and inter rack configurations. The following table lists 100GbE QSFP28 AOC of several famous brands.

Brands	QSFP28 AOC	Price
Cisco	QSFP-100G-AOC (1m-30m)	Above US$ 1,000
Arista	AOC-Q-Q-100G (1m-30m)	Above US$ 3,000
Juniper	JNP-QSFP28-AOC (1m-30m)	Above US$ 2,000
FS.COM	QSFP28 AOC (1m-30m)	From US$ 540 to US$ 630

Table 1. QSFP28 AOC Price Comparison

Switches Supporting QSFP28 AOC

Cisco, Arista, Juniper are three famous fiber optic transceiver manufactures. Transceiver modules and switches of these brands are very common in the market. As the demand for 100GbE data center keeps moving, these manufactures produce switches including 100GbE QSFP28 ports. Here I list four switches which can support QSFP28 AOC, Cisco Nexus 7700, Arista 7500R, Juniper QFX5110 and FS.COM S5850-48S2Q4C.

• Cisco Nexus 3232C—The Cisco Nexus 3232C switch is a low latency, dense, high-performance 100GbE switch designed for data center. It can not only meet customers’ current network needs but also suitable for future applications such as big data, cloud and virtualization. Each of 32 100GbE QSFP28 ports can operate at 10, 25, 40, 50, 100 GbE.
• Arista 7500R—Arista 7500R switches (7500R-36CQ, 7500R-36Q, 7500R-48S2CQ) is designed to lower power per 100GbE port and produce more reliable and dense network. The switches are available in a compact system design of 12, 8 and 4 slot. 7500R-36CQ has 36-port 100GbE QSFP line card. 7500R-36 owns 1/10GbE line card with two 100GbE QSFP28 ports. 7500R-48S2CQ is available with up to 6 100GbE QSFP28 ports.
• Juniper QFX5110—Juniper provides two switches with 100GbE port: QFX5110-48S and QFX5110-32Q. QFX5110-48S is a 10GbE/100GbE data center access switch offering 48x10GbE SFP+ port and 4x100GbE QSFP28 ports. QFX5110-32Q offers up to 32x40GbE QSFP+ ports, or 20x40GbE QSFP+and 4x QSFP28 ports.
• FS.COM offers two switches for 100GbE network: S5850-48S2Q4C and S8050-20Q4C. S5850-48S2Q4C provides 48x10GbE SFP+ ports, 2x40GbE QSFP+ ports and 4x100GbE QSFP28 ports. S8050-20Q4C has 2x40GbE QSFP+ ports and 4x100GbE QSFP28 ports.

Switch Brands	Model	Supported QSFP28 AOC	Switch Price
Cisco	Nexus 3232C	QSFP-100G-AOC (1m-30m)	About US$ 19,500.00
Arista	7500R-36CQ	100GBASE-AOC(3m to 30m)gggg	Average US$ 60,000.00
	7500R-36Q
	7500R-48S2CQ
Juniper	QFX5110-48S	QSFP28 AOC (10 m)gg	Above US$ 16,500.00
	QFX5110-32Q
FS.COM	S5850-48S2Q4C	Generic QSFP28 AOC (1m-30m)	US$ 6,900.00
	S8050-20Q4C

Table 2. Price Comparison of Switches Supporting QSFP28 AOC

Spend Less With FS.COM Switches and QSFP28 AOC

Based on Table 1 and Table 2, to build a 100GbE network with QSFP28 AOC will cost a lot, especially when you require for products from Cisco, Arista and Juniper manufacturers. By comparison, you can see the price of FS.COM switches for 100GbE network and QSFP28 AOC is quite lower. So FS.COM can help you spend less on building 100GbE network with QSFP28 AOC. But if you have already owned Cisco, Arista or Juniper switches, you can buy compatible QSFP28 AOCs which are more cost-effective and have been tested to assure 100% compatibility.

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

How to Convert SFP+ to 10GBASE-T/RJ45?

When migrating to 10G data center, you may have two choices: SFP+ or 10GBASE-T technology. 10GBASE SFP+ interface has always been widely deployed for 10 Gigabit ToR (top of rack) witches due to low power consumption. Due to advanced technology, switch manufacturers significantly reduce the power consumption and cost of 10GBASE-T server and switch. According to some researches, the cost of 10GBASE-T (RJ45 interface) switches is much lower than that of SFP+ switches. So many users prefer to add 10GBASE-T/RJ45 switches. But the problem is how to convert SFP+ to RJ45 port. This article will to introduce a necessary optical equipment–SFP+ to RJ45 media converter.

Introduction to SFP+ to RJ45 Media Converter

The secret to realize SFP+ to RJ45 conversion is 10 Gigabit SFP+ to RJ45 media converter. This converter has one 10G pluggable SFP+ port and one RJ45 port. SFP+ port is compatible with any SFP+ transceiver such as 10G SR SFP, 10G LR SFP and so on, which is the best suitable for your network and link lengths. 10 Gigabit SFP+ to RJ45 media converter is a cost-effective way to convert copper to fiber, or fiber to copper. Since it can deliver fast and reliable network access at longer distances than copper-based networks, it’s ideal for the applications in server rooms, workstations in remote areas or in other buildings.

How to Convert SFP+ to RJ45?

As the following figure shows, existing ToR switch only has some SFP+ interfaces. This switch is connected to an aggregation switch in the data center with multimode fiber patch cords. And the servers below are connected to the ToR switch with twinax DAC cables. Now considering that 10GBASE-T servers are less expensive, we decide to add new 10GBASE-T servers to the rack. Then we face a problem: how to integrate 10GBASE-T RJ45 ports servers into the the rack? To deal with this problem, we need to add 10 Gigabit Ethernet media converters to this rack system. First, connect the media converter with existing ToR switch by inserting one end of twinax DAC cables into the SFP+ port of the 10 Gigabit Ethernet media converter. Second, connecting media converter with the new 10GBASE-T servers by plugging Ethernet patch cords (better Cat6a) into RJ45 port of this media converter and 10GBASE-T servers.

As the 10GBASE-T servers are connected to 10 Gigabit SFP+ to RJ45 media converters over short Ethernet patch cords, so we can enjoy the advantage of 10GBASE-T short reach mode, which means all devices can operate at lower transmit power. Short reach mode, specified in the IEEE 10GBASE-T standard, conserves energy and produces less heat.

FS.COM SFP+ to RJ45 Media Converter Solutions

Part number	Description
21024	1x 10GBase-T to 1x 10GBase-X SFP+, Unmanaged
35609	1x 10GBase-T to 1x 10GBase-X XFP Unmanaged
35432	1x 10GBase-T to 1x 10GBase-X SFP+, Card Type
35433	1x 10GBase-T to 1x 10GBase-X XFP, Card Type
35610	1x 10GBase-T to 1x 10GBase-X SFP+ Managed
35431	1x 10GBase-T to 1x 10GBase-X XFP Managed

Conclusion

SFP+ to RJ45 conversion may be a very common issue in 10G data center. To solve this problem, the most cost-effective way is SFP+ to RJ45 media converter. It can bridge the interface disparities between equipment with 10GBASE-T RJ45 ports and existing rack servers or switches with fiber optic ports. FS.COM offers various high-performance 10G SFP+ to RJ45 media converters. For more product details, please contact us via email sales@fs.com.

Related article: 10G SFP or 10GBASE-T SFP for 10GbE Network?

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

How to Understand Tx Power and Rx Power of a Fiber Transceiver?

As we all know, single mode fiber optic transceiver is designed for long distance data transmission and multimode fiber optic transceiver is for short distance link. How to calculate the specific distance that a fiber optic transceiver can support at a certain occasion? What factors are crucial to the transmission distance? Do you have any idea of Tx (transmit) power and Rx (receive) power level of a fiber optic transceiver? This article will show you by introducing 10GBASE-SR SFP+ and 10GBASE-LR SFP module.

Tx Power and Rx Power of a Fiber Transceiver

First, let’s understand the most two important factors of the fiber optic transceiver: Tx power and Rx power. The optical Tx power is the signal level leaving that device and it should be within the transmitter power range. The Rx power is the incoming signal level being received from the far end device and it should fall within the receive power range.

10GBASE-SR SFP+ is a multimode fiber transceiver and can support the distance of 300 m over OM3 multimode fiber patch cable. While 10GBASE-LR SFP module is a single mode type and can run the network distance up to 10 km over single mode fiber patch cords. Before purchasing 10GBASE SFP+ module, you must carefully read the product details. The following lists the product details about 10GBASE-SR SFP+ and 10GBASE-LR SFP module from Fiberstore. As showing below, Tx power of this Cisco compatible 10GBASE-SR SFP+ is between -7.3 dB and 1 dB. The maximum receive power is below -11.1 dB. With regard to Cisco compatible 10GBASE-LR SFP module, Tx power is from -8.2 to 0.5 dB and the maximum Rx power is -14.4 dB

Tx Power and Rx Power of 10GBASE-SR SFP+

Tx Power and Rx Power of 10GBASE-LR SFP+ Module

 

Tx Power and Rx Power VS. Optical Power Budget

To calculate the specific distance of a fiber optic transceiver, we need to know its optical power budget (maximum allowable loss).

Optical power budget = Tx power - Rx power

Therefore, according to the Tx power and Rx power, we can calculate the maximum allowable loss of 10GBASE-SR SFP+ and 10GBASE-LR SFP module.

Optical Power Budget of 10GBASE-SR SFP+

Min Tx Power = -7.3 dB
Max Rx Power = -11.1 dB
Optical power budget (maximum allowable loss) = (-9.5 dB) - (-11.1 dB)=1.6 dB

Optical Power Budget of 10GBASE-LR SFP+ Module

Min Tx Power = -8.2dB
Max Rx Power = -14.4 dB
Optical power budget (maximum allowable loss) = (-8.2 dB) - (-14.4 dB)=6.2 dB

Tx Power and Rx Power VS. Transmission Distance

Except optical power budget, we have to consider other factors including the link length, fiber optical connectivity components, fusion splicing points and some unpredictable fiber attenuation caused by fiber patch cable bending (usually the attenuation is about 3 dB). The loss of each connector is 0.6 dB and 0.1 dB of each fusion splicing point. Suppose we use 10GBASE-LR SFP+ module to build a network covering 2 connectors, 4 fusion splicing points. This module is interfaced with LC single mode fiber patch cord. If the single mode fiber cable has the wavelength of 1310 nm, the cable loss is about 0.35 dB per kilometer.

The worst optical loss = Power Budget – Total Optical Power Loss=6.2 dB - 1.2dB (2x0.6 dB) - 0.4dB (0.1x4) - 3dB (safety factor) = 1.6 dB

Worst case distance = {Worst case OPB, in dB} / [Cable Loss, in dB/km]=1.6dB/0.35dB/km
So we can get 10GBASE-LR SFP+ module can support at least 4.57 km at this occasion. Data transmission distance is mainly influenced by the optical power budget and fiber cable loss. From the above content, the optical power budget of 10GBASE-SR SFP+ is smaller than that of 10GBASE-LR SFP+ module. The more the optical power budget, the further the fiber transceiver can support. What’s more, the cable loss of multimode fiber cable is larger than that of single mode fiber cable. Obviously 10GBASE-LR SFP+ module can support longer link distance than 10GBASE-SR SFP+.

Note: The optical power budget is based on a theoretical calculation, and is just for reference. The transmission distance should be calculated based on the power budget of fiber transceiver module tested on the switch and some practical attenuation.

Conclusion

Tx power and Rx power level of a transceiver are the main factors of transmission distance. The more the optical power budget, the better the transceiver. Before purchasing a transceiver, you’d better calculate the optical power budget according to transceiver module details.

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