• For each blank, choose the best answer from the four choices and write down on the answer sheet.
   In　（66）　 the strength of the carrier signal is varied to represent binary 1 or 0.
(67) is a system that can map a name to an address and conversely an address to an name.
(68)   is a three-way handshaking authentication protocol that it’s packets are encapsulated in the point-to-point protocol
(69)  is an approach that enables an ATM Switch to behave like a LAN switch.
(70)  is an guided media which is made of glass or plastic and transmits signals in the form of light.

(66)  A  ASK  B PSK C FSK D FDM
(67)  A  NAT  B NCP  C DDN  D DNS
(68)  A  PPP  B PAP   C CHAP  D LCP
(69)  A VLAN B LANE  C VPN  D IPOA
(70)  A  Coaxial cable  B Optical fiber    C Unshielded  Twisted-pair Cable  D Shielded  Twisted-pair Cable

答案：(66) A （67）D （68）C（69）B（70）B

• In the following essay, each blank has four choices. Choose the best answer and write down on the answer sheet.

  To a router, a flow is a （71） of packets that share the same characterstics , such as traveling the same （72） ,using the same （73） ,having the same kind of security, and so on. A router that supports the handling of flow labels has a （74） table. The table has an entry for each active flow label; each entry defines the （75） required by the corresponding flow label.
(71)  A  sequence  B stream  C Queues  D flow 
(72)  A  path  B rout  C circuit  D way
(73)  A  source   B  resources  C route  D Entry
(74)  A flow table  B flow label  C rout table  D  Tag table
(75)  A quality  B Traffic  C services  D route

答案：(71) A （72）A （73）B（74）B（75）C