Patch Cord Selection Details for 40G QSFP+
The enormous increase of demands for networking infrastructure which can provide additional network capacity and bandwidth, has boosted the migration tide from 10 Gigabit Ethernet (GbE) to 40GbE. Numerous things need to be planned and designed for this 40G migration. Whether the switches can support such a high speed Ethernet or not? Which kind of optical transceiver performances best on the switches or costs least? Many products are available in telecommunication market today to support 40G, and 40G QSFP+ transceivers (Quad Small Form-factor Pluggable transceivers) are thought as the most economic and effective transceivers for 40G migration.
Patch Cords Matter in 40GbE Transmission
The switches, no matter how advanced they are, all need to be connected together for 40GbE transmission. To accomplish the connections between these switches, patch cords are usually linked to fiber optic transceivers which are plugged in Ethernet switches. The quality of these connections has great influence on the reliability and stability of the whole 40G network. And 40G connectivity has become much more complex. Thus, selecting the proper fiber patch cables is the primary task in 40G migration. This text details fiber patch cord selection for 40G QSFP+ transceivers.
Patch Cord Selection for 40G QSFP+
Patch cords selection is a challenge for 40G migration because of the switch connections necessity, the transmission principle of the signals, as well as the high density trend of 40G transmission. When choosing patch cords for 40G QSFP+ transceivers, three factors should be considered: cable type, connector type and switch port.
Selecting Cable Type
When signals run through different fiber optic cables, their performances are totally different, whether with the same or different wavelengths. As such, the selection of the cable type becomes important.
When buying patch cord for 40G QSFP+, a typical question is: Can a 40GBASE universal QSFP+ transceiver working on wavelength of 850nm operate over OM1. The answer is yes, but not suggested. Why? The transmission distance and quality would be limited by using OM1 with 40G QSFP+ transceiver. OM1 is only advised for 100Mb/s and 1000Mb/s transmission. Two upgraded cables—OM3 and OM4 are recommended for 40G QSFP+ transceivers in short distance.
IEEE has specified standards for 40G transmission in both long distance and short distance, which are 40GBASE-SR4 and 40GBASE-LR4. The latter is suggested for 40G transmission over single-mode fiber in long distance up to 10km. In contrast, the former is for 40G transmission in short distance over multi-mode fiber—OM3 (up to 100 meters) and OM4 (up to 150 meters). OM3 and OM4, which are usually aqua-colored, are accepted economic solutions for 40G in short distance with lower insertion loss and higher bandwidth. Take QSFP-40G-SR4-S for example, this Cisco compatible 40GBASE-SR4 QSFP+ transceiver listed in Fiberstore realizes 100m reach on OM3 and 150m reach on OM4.
Selecting Connector Type
The choice of connector type of the patch cords should depend on the interface of 40G QSFP+ transceiver. Currently there are two interfaces commonly adopted by 40G QSFP+ transceiver: MTP and LC. Usually 40G QSFP+ transceiver with MPO interface is designed for short transmission distance and LC for long transmission distance. Like JNP-QSFP-40G-LX4, this 40GBASE-LX4 QSFP+ uses LC as its connector and establishes 40G links with distance up to 2km.
Selecting Switch PortRight selection of switch port for 40G QSFP+ transceiver can increase the network flexibility largely and effectively. Two most common examples in 40G applications are listed below. One is 40G QSFP+ to 40G QSFP+ cabling, the other one is 40G QSFP+ to SFP+ cabling. When 40G port is needed to be connected with 10G port, the second cabling assembly is deployed. Like QSFP-4X10G-AOC5M, this cabling assembly contains the breakout patch cable with MTP connector on one end and four LC duplex connectors on the other end.
Conclusion
While selecting the right patch cords for 40G QSFP+ transceivers, cable type, connector type and switch port all need your attention. These three factors are closely related to the transmission distance, network flexibility and reliability of the whole 40G network. Fiberstore provides various kinds of fiber patch cords for your high-performance 40G network. For more information about patch cord solutions for 40G QSFP+ transceivers, you can visit Fiberstore.
