1. By using the above Figure that represents the loss (dB/km) of an optical fiber versus wavelength, calculate the loss in dB at the corresponding distance of the fiber by completing the following table:

	dB at 800nm	dB at 1000nm	dB at 1200nm
1 km
20 km

2. What is the difference between internet and Internet? A network must be able to meet a certain number of criteria, such as reliability and security. Explain both of them.

* use SM format

100 50 10 F 5 E 0.5 0.1 0.05 0.01 800 1000 1200 Wavelength (nm) 1400 1600 1800