Why Are the Rates of the FE and GE Ports Inconsistent with the Standard?

Hello, friend!

When the board that supports FE optical ports receives FE services, the port rate is 125 Mbit/s. The port rate needs to be converted according to the 4B/5B encoding rule. After the conversion, the port rate is 100 Mbit/s.

When the board that supports GE optical ports receives GE services, the port rate is 1.25 Gbit/s. The rate needs to be converted according to the 8B/10B encoding rule. After the conversion, the rate is 1000 Mbit/s.

Thanks!