在结构化布线系统设计时,配线间到工作区信息插座的双绞线最大不超过90米,信息插座到终端计算机网卡的双绞线最大不超过( )米。
A.90
B.60
C.30
D.10
Network Addres Translation(NAT) is an Internet standard that enbles a local-area network to use one set of IP addresses for internet traffic and another set of ( ) IP addresses for external traffic. The main use of NAT is to limit the number of public IP addresses that an organization or company must use, for both economy and ( ) purposes. NAT remaps an IP address space into another by modifying network address information in the ( ) header of packets while they are in transit across a traffic routing device. It has become an essential tool in conserving global address space in the face of ( ) address exhaustion. When a packet traverses outside the local network, NAT converts the private IP address to a public IP address. If NAT runs out of public addresses,the packets will be dropped and ( )"host unreachable"packets will be sent.
(1) A. local
B. private
C. public
D. dynamic
(2) A. political
B. fairness
C. efficiency
D. security
(3) A.MAC
B. IP
C.TCP
D. UDP
(4) A. IPv4
B. IPv6
C. MAC
D. logical
(5) A. BGP
B. IGMP
C. ICMP
D. SNMP