Migrate to 40G Network Cost-effectively with BiDi QSFP+ Transceiver

As data center consolidation, server virtualization, and new applications require higher data transmission speed, it is imperative to migrate from 10G network to 40G network. However, to support the 40G connectivity, data center managers have to upgrade the existing 10G cabling infrastructure, which could be too expensive or disruptive to allow data center to quickly adapt and migrate to the 40G technology. Therefore, innovative 40G BiDi QSFP+ transceiver, which allows reuse of existing 10G fiber infrastructure for 40G connections, is designed to solve this problem. However, what is BiDi QSFP+? How does it work? And what are the advantages of BiDi QSFP+ over traditional QSFP+? This post will answer these questions one by one.

What Is BiDi QSFP+ Transceiver?

BiDi QSFP+ transceiver is a latest product used for 40G short-reach data communication and interconnect applications. Compliant with the QSFP MSA specification, it is terminated with a duplex LC connector interface to transmit data over laser-optimized OM3 and OM4 multimode fiber cables for the length of up to 100 m and 150 m respectively, that is the same as the traditional QSFP-40G-SR4 (like Arista QSFP-40G-SR4). This 40G transceiver has two 20G channels, and each channel transmits and receives two wavelengths over a single multimode fiber strand. The following image shows a Cisco 40GBase-SR BiDi QSFP+ transceiver.


How Does BiDi QSFP+ Work with Existing 10G Optics?

As we all know, 40GBase-SR4 QSFP transceiver uses four 10G lanes to support 40G through a 12-fiber MTP-MPO interface, with four for transmitting and receiving and the rest are unused. However, a BiDi QSFP+ transceiver can accomplish both the transmitting and receiving via a duplex LC patch cable. So it can be deployed in the existing 10G cabling infrastructure, which also uses duplex transmission mode.

Inside this module, four channels each of 10G signal transmission and reception are converted to two bidirectional channels of 20G signals over two different wavelengths (usually 850 nm and 900 nm) respectively (shown in the following picture). The signal is sent to the target device via 850 nm, then the signal from the target device is sent via 850 nm on the other fiber. This principle also works for the signals on 900 nm. This is why BiDi QSFP+ can achieve the migration from 10G to 40G without changing the existing infrastructure. It is more straightforward than the traditional 40G connections for short distance.


Economic Advantages of BiDi QSFP+ Transceiver

As we have mentioned above, a BiDi QSFP+ transceiver can give you 40G over your existing 10G cable plant, which means that you can connect your top-of-rack switches using the same multimode fiber and patch cables you are using right now, but get 40G performance. So data center managers won’t worry about the high cost of changing cable plant. Besides, compared to traditional QSFP+ transceivers, BiDi QSFP+ transceivers uses fewer fibers (about 2 fibers) to support 40G signal transmission, which can save another amount of money for you. For example, if you are building a new 40G data center fabric in the traditional way, you would need to run 8-multimode fiber strands between your access and aggression layer: a cost of $2000 per port. However, with BiDi QSFP+ transceivers, you can get 40G performance using just 2 fiber strands: a quarter of cabling. For a standard server rack (384 ports), that translates to a savings of more than $550,000.


Through the information we have discussed above, there is no doubt that 40G BiDi QSFP+ transceiver is really a cost-effective solution for the migration from 10G to 40G network. Although the price of BiDi QSFP+ transceivers are higher than that of common QSFP+ transceivers, BiDi QSFP+ transceiver utilizes much fewer fibers per unit distance. For many networks, the cost savings of utilizing less fibers far exceed the higher purchase price of BiDi QSFP+ transceivers. With advanced manufacturing facilities, strict reliability test and quality control, FS.COM ensures that our customers can get the highest-quality BiDi QSFP+ transceivers with the lowest price. We also provide plenty of traditional QSFP+ transceiver modules, like Cisco 40G-QSFP-CSR4, for your needs. Besides QSFP+, there are also many other types of fiber optic transceivers for different Ethernet networks, such as SFP, SFP+, 100G QSFP28. If you are looking for any related products, please visit FS.COM or contact sales@fs.com.

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