As the market research speculated last year, 100GbE (Gigabit Ethernet) modules is really hot this year. After several years of evolution, there are various of 100GbE modules available in the market, including CFP, CFP2, CFP4, QSFP28 and CPAK (Cisco). Today, I wanna have an overview of them via comparing them from several respects.
100GbE form factor undergoes a five-year evolution and has developed to 2nd generation now. As shown below, the 1st generation of 100 GbE uses 10×10 Gbps electrical lanes and large CFP media modules; The 2nd generation of 100 GbE will use 4×25 Gbps electrical lanes and smaller CFP2/CFP4/25 Gbps QSFP modules. (View 100Gbase-SR10 CFP vs. 100Gbase-SR4 QSFP28)
With the development of form factor, each module increases density, while reducing cost and power. The following diagram shows us the density comparison of different kinds of 100G form factors. CFP2 enables 1Tb/s per blade while CFP4/QSFP28 enables ~4Tb/s per blade.
Different technologies are used to achieve 100GbE transmission in a module. For transmit side of the module, three main kinds of technologies are used, as shown below.
