Posting this blog on behalf of Mark Nowell, Distinguished Engineer, Datacenter BU.

The hallmark of optical bidirectional (BiDi) transceivers is how the technology enables users to maximize their fiber cabling infrastructure costs through more efficient deployment of ports, patch panels, cabling, etc. It’s the old “do more with less” principle that has made BiDi technology so popular in the optical networking market. Indeed, Cisco estimates that we will ship the 2-millionth BiDi module to customers sometime next quarter.

Even the most efficient network infrastructure, however, was not designed for the number of users, devices, and applications that are coming online every day through new technology paradigms such as IoT. Cisco Consulting Services forecasts that the Internet of Things (IoT) will triple the number of devices generating traffic on IP networks. All told, there will be 50 billion smart devices connecting to global networks by 2020. All indications are, though, that this may be a lowball number with an astounding one trillion devices being the reality in less than two decades.

The implications are that networking infrastructure capacity must be able to keep pace with the phenomenal and exponential explosion demands. This is why Cisco, as a founding member of the 400G BiDi MultiSource Agreement (MSA) is hard at work in preparation for the next upgrade paths that will help customers deal with the ever-complex demands on their networks.

The Path to 400 GbE Optical

One specific path is to define an optical networking solution that will quadruple existing 100G BiDi technology.  Cisco is working with the industry to extend BiDi technology to 400G, which will leverage the 4+4 parallel multimode fiber typically utilized for the 40GBASE-SR4 and 100GBASE-SR4 interfaces. An advantage of the 400G BiDi approach is that the optical specs will be identical to the 100G BiDi specs so the 400G BiDi module can operate in a breakout configuration supporting four individual 100G QSFP28 module.

As we’ve discussed previously (QSFP-DD Optical form factor: An evolutionary approach to 400GbE Interconnect), the industry is broadly adopting the QSFP-DD module form factor for 400 GbE and it will also support the 400G BiDi solution.  With its promise of lower cost and lower power than single mode fiber modules, 400G BiDi is of interest to both Cloud and Enterprise Data Center applications as each module can support 400GE BiDI or Dense (4x) 100GE BiDi with backward compatibility to existing technologies as investment protection.


Even with technologies such as BiDi optical, today’s networking infrastructures are still under strain to deal with the massive influx of new devices, users, and data that are defining life in the digital age for businesses and consumers alike. The work being done to standardized 400 GbE BiDi optical is a necessary upgrade path to right-size infrastructure for the many and diverse demands. Cisco is on the forefront of this exciting development and is the right company for customers to speak with in evaluating their options.

For more information, please visit  www.cisco.com/go/nexus9000



Tony Antony