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