按制定标准的不同层次和适应范围，标准可分为国际标准、国家标准、行业标准和企业标准等，(17)制定的标准是国际标准。

(82)

(81)

(79)

(80)

(71) In the strength of the carrier signal is varied to represent binary 1 or 0.

  (72) is a system that can map a name to an address and conversely an address to an name.

  (73) is a three-way handshaking authentication protocol that it's packets are encapsulated in the point-to-point protocol

  (74) is an approach that enables an ATM Switch to behave like a LAN switch.

  (75) is an guided media which is made of glass or plastic and transmits signals in the form. of light.

(76)

(77)

(74)

(75)

(72)