Networking

As we all know, the standard specifies MPO as a connector to the 40GBASE-SR4/CSR4 QSFP+ transceiver. To connect a QSFP+ to QSFP+, we usually use a MTP 12-fiber trunk cable. In the 40GBASE-SR transmission, there are eight fibers associated with the channel—four fibers for the TX signal and four fibers for the RX signal. Therefore only 8 of the 12 fibers are used, where the remaining four are not used, and can optionally be not present in the cable. So we can also choose a MTP 8-fiber trunk cable for connectivity. This article explains 40GBASE-SR4/CSR4 QSFP+ to 40GBASE-SR4/CSR4 QSFP+ cabling selections. How to Choose Right  MTP Trunk Cables? In addition to using a MTP 8-fiber trunk cable or MTP 12-fiber trunk cable, there are a number of other factors also needed to be considered when to choose a right MTP trunk cable for 40GBASE-SR4/CSR4 QSFP+ connectivity. Use single-mode or multimode MTP trunk cable? In the market, both single-mode and multiode M...

As we all know, 40GBASE-SR4 QSFP+ transceivers usually use a parallel multimode fiber (MMF) link to achieve 40G. It offers 4 independent transmit and receive channels, each capable of 10G operation for an aggregate data rate of 40G over 100 meters of OM3 MMF or 150 meters of OM4 MMF. However, for 40GBASE-LR4 QSFP+ transceivers, there are two kinds of links. One is coarse wavelength division multiplexing (CWDM) and the other is parallel single-mode fiber (PSM). What’s the difference between them? In this article, I will show their working principles to you respectively. 40GBASE-LR4 CWDM QSFP+ Transceiver The 40GBASE-LR4 CWDM QSFP+ transceiver, such as QSFP-40GE-LR4, is compliant to 40GBASE-LR4 of the IEEE P802.3ba standard. It contains a duplex LC connector for the optical interface. The maximum transmission distance of this transceiver is 10km. To minimize the optical dispersion in the long-haul system, single-mode fiber (SMF) has to be used. T...

40GbE Overview 40GbE (Gigabit Ethernet) is Ethernet standard developed by the IEEE 802.3ba task force, enabling the transfer of Ethernet frames at speeds of up to 40 gigabits per second (Gbps). It also addresses physical layer specifications for communication across backplanes, copper cabling, multimode fiber and single-mode fiber. 40GbE standard was approved as an IEEE standard on 17 June 2010. Now, 40 Gigabit Ethernet is already upon us. It become a new generation of high-speed, high-demand, computing applications and technologies. Like 1GbE or 10GbE network, the heart of the 40GbE network layer is a pair of transceiver modules which are connected by a patch cable. The transceiver modules and patch cables seem to be the most basic components for transmission. The former is used to plugged into either network servers or various of components such as interface cards and switches. Transceivers 40GbE transceivers are being developed along several standard form factors. CFP (C ...