题目内容：
根据下列题干，回答题：（ 1 ）In the strength of the carrier signal is varied to represent binary 1 or 0．
（ 2 ）is a system that can map a name to an address and conversely an address to an name．
（ 3 ）is a three-way handshaking authentication protocol that it's packets are encapsulated in the point-to-point protocol
（ 4 ）is an approach that enables an ATM Switch to behave like a LAN switch．
（ 5 ）is an guided media which is made of glass or plastic and transmits signals in the form of light．
请选择（1）处最佳答案：
参考答案：
答案解析：