Computer Networks -Latest Exam Questions and
Answers
A client-server system uses a satellite network, with the satellite at a height of 40,000 km. What
is the best-case delay in response to a request (in msec)? - ✔✔533
A factor in the delay of a store-and-forward packet-switching system is how long it takes to
store and forward a packet through a switch. If switching time is 20 µsec, is this likely to be a
major factor in the response of a client-server system where the client is in New York and the
server is in California? - ✔✔No
A factor in the delay of a store-and-forward packet-switching system is how long it takes to
store and forward a packet through a switch. If switching time is 20 µsec, what percentage of
the trip time in the response of a client-server system where the client is in New York and the
server is in California is due to switching delay? - ✔✔4
A server sends packets to a client via satellite. The packets must traverse one or multiple
satellites before they reach their destination. The satellites use store-and-forward packet
switching, with a switching time of 100 µsec. If the packets travel a total distance of 29,700 km,
how many satellites do the packets have to pass if 1% of the delay is caused by packet
switching? - ✔✔10
Another advantage of having international standards for network protocols is that widespread
use of any standard will give it economies of scale, as with VLSI chips. - ✔✔True
If the unit exchanged at the data link level is called a frame and the unit exchanged at the
network level is called a packet, do frames encapsulate packets or do packets encapsulate
frames? - ✔✔Frames encapsulate packets
Layers one, two, and three of the OSI Model are implemented in the end systems but not in the
routers in the network core. - ✔✔False
,One advantage of having international standards for network protocols is that if everyone uses
the standard, everyone can talk to everyone. - ✔✔True
One disadvantage of using international standards is that if everyone uses the standard,
everyone can talk to everyone. - ✔✔False
Suppose that two network endpoints have a round-trip time of 100 milliseconds, and that the
sender transmits five packets every round trip. What will be the sender's transmission rate for
this round-trip time, assuming 1500-byte packets? - ✔✔5 × 1500 = 7,500 bytes per 100
milliseconds. So, the rate is 75,000 bytes per second.
Wireless networks have surpassed wired networks in popularity, even though they typically
provide less bandwidth. Select all the reasons listed below that are true and correct. -
✔✔Installing wires in buildings can be expensive.
Wireless networks allow people to move around, instead of tying them to a wall.
A potential problem is battery life, since most wireless devices tend to be mobile.
Although wireless networks provide lower bandwidth than wired networks, their bandwidth
has become large enough to support applications that people find meaningful.
Wireless networks are by nature more secure than wired networks.
Which of the following descriptions below correspond to a "nuts-and-bolts" view of the
Internet? - ✔✔A collection of hardware and software components executing protocols that
define the format and the order of messages exchanged between two or more communicating
entities, as well as the actions taken on the transmission and/or receipt of a message or other
event.
A place I go for information, entertainment, and to communicate with people.
, A collection of billions of computing devices, and packet switches interconnected by links.
A platform for building network applications.
A "network of networks".
Which of the following descriptions below correspond to a "services" view of the Internet? -
✔✔A platform for building network applications.
A place I go for information, entertainment, and to communicate with people.
A collection of billions of computing devices, and packet switches interconnected by links.
A collection of hardware and software components executing protocols that define the format
and the order of messages exchanged between two or more communicating entities, as well as
the actions taken on the transmission and/or receipt of a message or other event.
Which of the following human scenarios involve a protocol? - ✔✔One person asking, and
getting, the time to/from another person.
A person sleeping.
A person reading a book.
A student raising her/his hand to ask a really insightful question, followed by the teaching
acknowledging the student, listening carefully to the question, and responding with a clear,
insightful answer. And then thanking the student for the question, since teachers love to get
questions.
Two people introducing themselves to each other.
Which of the following physical layer technologies has the highest transmission rate and lowest
bit error rate in practice? - ✔✔Fiber optic cable
Answers
A client-server system uses a satellite network, with the satellite at a height of 40,000 km. What
is the best-case delay in response to a request (in msec)? - ✔✔533
A factor in the delay of a store-and-forward packet-switching system is how long it takes to
store and forward a packet through a switch. If switching time is 20 µsec, is this likely to be a
major factor in the response of a client-server system where the client is in New York and the
server is in California? - ✔✔No
A factor in the delay of a store-and-forward packet-switching system is how long it takes to
store and forward a packet through a switch. If switching time is 20 µsec, what percentage of
the trip time in the response of a client-server system where the client is in New York and the
server is in California is due to switching delay? - ✔✔4
A server sends packets to a client via satellite. The packets must traverse one or multiple
satellites before they reach their destination. The satellites use store-and-forward packet
switching, with a switching time of 100 µsec. If the packets travel a total distance of 29,700 km,
how many satellites do the packets have to pass if 1% of the delay is caused by packet
switching? - ✔✔10
Another advantage of having international standards for network protocols is that widespread
use of any standard will give it economies of scale, as with VLSI chips. - ✔✔True
If the unit exchanged at the data link level is called a frame and the unit exchanged at the
network level is called a packet, do frames encapsulate packets or do packets encapsulate
frames? - ✔✔Frames encapsulate packets
Layers one, two, and three of the OSI Model are implemented in the end systems but not in the
routers in the network core. - ✔✔False
,One advantage of having international standards for network protocols is that if everyone uses
the standard, everyone can talk to everyone. - ✔✔True
One disadvantage of using international standards is that if everyone uses the standard,
everyone can talk to everyone. - ✔✔False
Suppose that two network endpoints have a round-trip time of 100 milliseconds, and that the
sender transmits five packets every round trip. What will be the sender's transmission rate for
this round-trip time, assuming 1500-byte packets? - ✔✔5 × 1500 = 7,500 bytes per 100
milliseconds. So, the rate is 75,000 bytes per second.
Wireless networks have surpassed wired networks in popularity, even though they typically
provide less bandwidth. Select all the reasons listed below that are true and correct. -
✔✔Installing wires in buildings can be expensive.
Wireless networks allow people to move around, instead of tying them to a wall.
A potential problem is battery life, since most wireless devices tend to be mobile.
Although wireless networks provide lower bandwidth than wired networks, their bandwidth
has become large enough to support applications that people find meaningful.
Wireless networks are by nature more secure than wired networks.
Which of the following descriptions below correspond to a "nuts-and-bolts" view of the
Internet? - ✔✔A collection of hardware and software components executing protocols that
define the format and the order of messages exchanged between two or more communicating
entities, as well as the actions taken on the transmission and/or receipt of a message or other
event.
A place I go for information, entertainment, and to communicate with people.
, A collection of billions of computing devices, and packet switches interconnected by links.
A platform for building network applications.
A "network of networks".
Which of the following descriptions below correspond to a "services" view of the Internet? -
✔✔A platform for building network applications.
A place I go for information, entertainment, and to communicate with people.
A collection of billions of computing devices, and packet switches interconnected by links.
A collection of hardware and software components executing protocols that define the format
and the order of messages exchanged between two or more communicating entities, as well as
the actions taken on the transmission and/or receipt of a message or other event.
Which of the following human scenarios involve a protocol? - ✔✔One person asking, and
getting, the time to/from another person.
A person sleeping.
A person reading a book.
A student raising her/his hand to ask a really insightful question, followed by the teaching
acknowledging the student, listening carefully to the question, and responding with a clear,
insightful answer. And then thanking the student for the question, since teachers love to get
questions.
Two people introducing themselves to each other.
Which of the following physical layer technologies has the highest transmission rate and lowest
bit error rate in practice? - ✔✔Fiber optic cable
