For a truly free, legal, and high-quality alternative, use the free courses (in Spanish) or the OpenCourseWare materials from Spanish universities.

The book covers the aligned with Spanish official curricula (LOE, LOMCE, LOMLOE). Typical chapters include:

and the use of fiber optics, which are vital for modern high-speed data transmission. A "good essay" on this topic must acknowledge that a network's reliability is only as strong as its physical foundation. The book emphasizes the IEEE 802 standards