Oh, Bi the Way…

Hidden in Cisco's Nexus 9000 and Application Centric Infrastructure news was another nifty announcement: an optical transceiver that delivers 40Gbps speeds using older 10Gbps fiber and standard connectors.  Cisco's "BiDi" optical transceivers solve a sticky cabling problem in an elegant way.  

For many network managers, the dust had hardly settled on the transition from older gigabit OM1/OM2 fiber (the “orange” stuff) to OM3 fiber (“aqua” colored) for 10Gbps, when 40Gbps Ethernet came out -- with yet another cabling standard and the QSFP I/O interconnect.  

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Initial 40Gbps Ethernet hardware uses the MPO-12F connector, complicated, expensive, and requiring 12 strands (even though only eight are used).  That’s because initial 40Gbps Ethernet has been built by bundling together four 10Gbps connections.  

In some cases, four 10Gbps connections are what you want, and some 40Gbps products (including the Cisco Nexus 9000) let you turn a 40Gbps port into four 10Gbps ports with special breakout cables. But if you really want the 40Gbps connection, new cabling, connectors, and higher densities all work together to increase costs.  

Cisco’s BiDi optics use standard 10Gbps OM3 (and OM4) fiber and standard dual-LC connectors, offering 40Gbps speeds on a single pair of fiber strands at distances of up to 100 meters (up to 150 meters for OM4 fiber). And, the BiDi parts cost about the same as standard QSFP transceivers. Unfortunately, the BiDi parts are not supported on older Cisco 40Gbps hardware. For supported devices, BiDi is a no-brainer decision for 40Gbps deployments based on Nexus 6000, 7000, and 9000 hardware.