Introduce in detail what is a submarine cable Background The Internet has become an indispensable part of our lives, and the submarine cable is the "central nerve" of the Internet. It carries more than 90% of the world's international voice and data transmission. Without it, the Internet is just a local area network. At present, there are more than 400 submarine optical cables in the world, with a total length of about 1.2 million kilometers, which is three times the distance from the earth to the moon. Only 5% of the international data transmission on the Internet relies on land...