Chapter 1 Computer Networks and the Internet
1．The ( ) is a worldwide computer network, that is, a network that interconnects millions of computing devices throughout the world.
A public Internet
C switch net
D television net
2．Which kind of media is not a guided media? ( )
A twisted-pair copper wire
B a coaxial cable
C fiber optics
D digital satellite channel
3．Which kind of media is a guided media? ( )
A geostationary satellite
B low-altitude satellite
C fiber optics
D wireless LAN
4．The units of data exchanged by a link-layer protocol are called ( ).
D bit streams
5．Which of the following option belongs to the circuit-switched networks? ( )
C VC networks
D both A and B
6．( )makes sure that neither side of a connection overwhelms the other side by sending too many packets too fast.
A Reliable data transfer
B Flow control
C Congestion control
D Handshaking procedure
7．( ) means that the switch must receive the entire packet before it can begin to transmit the first bit of the packet onto the outbound link.
A Store-and-forward transmission
C End-to-end connection
8．Datagram networks and virtual-circuit networks differ in that ( ).
A datagram networks are circuit-switched networks, and
virtual-circuit networks are packet-switched networks.
B datagram networks are packet-switched networks, and
virtual-circuit networks are circuit-switched networks.
C datagram networks use destination addresses and virtual-circuit
networks use VC. numbers to forward packets toward their
D datagram networks use VC. numbers and virtual-circuit networks
use destination addresses to forward packets toward their destination. 9．In the following options, which one is not a guided media? ( )
A twisted-pair wire
B fiber optics
C coaxial cable
10．Processing delay does not include the time to ( ).
A examine the packet’s header
B wait to transmit the packet onto the link
C determine where to direct the packet
D check bit-error in the packet
11．In the following four descriptions, which one is correct? ( )
A The traffic intensity must be greater than 1.
B The fraction of lost packets increases as the traffic intensity
C If the traffic intensity is close to zero, the average queuing delay
will be close to zero.
D If the traffic intensity is close to one, the average queuing delay
will be close to one.
12．The Internet’s network layer is responsible for moving network-layer packets known as ( ) from one host to another.
13．The protocols of various layers are called ( ).
A the protocol stack
D network protocol
14．There are two classes of packet-switched networks: ( ) networks and virtual-circuit networks.
15．Access networks can be loosely classified into three categories: residential access, company access and ( ) access.
D city area