QSFP28 and CFP: Out with the Old and in with the New

By Ken Van Orman, Senior Product Manager Hardware and Platforms, Spirent Communications

In this year’s Ethernet Alliance OFC demo, QSFP28 makes an appearance and CFP takes a bow. This reflects the trend in the industry to aggressively bring 100GE density up and costs down. CFP4 is half the width of CFP2, which is half again the width of CFP. QSFP28 has the same footprint and faceplate density as QSFP+ and is just slightly smaller than CFP4. On paper, QSFP28 seems to have the density advantage over CFP4, but CFP4’s higher maximum power consumption gives it the advantage on longer reach optical distances. Only time will tell how this all plays out but in the meantime, there is a richness of choice in the 100G interconnect market.

The important takeaway – and where I see a lot of confusion for those new to 100GE – is that the form factor does not matter when the media connecting them is the same. For example, 100GBASE-LR4 whether from CFP, CFP2, CFP4 or CPAK (more on this later) will interoperate, and you can see this firsthand in the Ethernet Alliance booth.

Rounding out this year’s demo is a mix of 10GE SFP+ and 40GE QSFP+ connections. The QSFP+ interconnects are hard to distinguish from QSFP28 100GE connections so talk to the booth representatives to understand what the actual differences are.

CPAK is another newcomer to this year’s demonstration. This is a proprietary form factor from Cisco but the interfaces demonstrated are IEEE standards and will interoperate with the same interfaces supported by other form-factors. Other vendors participating in the demo are Amphenol; Broadcom; Brocade; Cisco; CommScope; Finisar; Hitachi Cable; Ixia; Juniper; Spirent; and Teledyne LeCroy.

Speaking of QSFP28, I expect to see quite a bit of this form factor throughout the exhibition hall. In the past, a lot of optical transceiver vendors displayed products but this year, I expect to see more switches, NICs, and testers demonstrating QSFP28 product.

Stop by the Ethernet Alliance booth #2531 at OFC 2015 to see our live demonstration, talk to the booth reps about the latest Ethernet technologies, and let us know what you would like to see next year. See you on the show floor!