Vertical Eye Closure Penalty (VECP) is a measurement method for an optical load test in 10 Gigabit Ethernet (10GbE) and 100 Gigabit Ethernet
(100GbE). VECP cannot be measured directly, but can only be determined mathematically. For this purpose, the VECP measurement uses the eye diagram and is calculated from the optical modulation amplitude, Optical Modulation Amplitude (OMA), and the smallest inner eye opening (A0). The logarithm of the ratio of these two quantities OMA/A0 is the Vertical Eye Closure Penalty (VECP).