Computer Networks - Test 1
1.3 According to the text, is it possible to develop Internet applications without understanding
the architecture of the Internet and the technologies? Support your answer. - ANS-Answer: Yes,
possible to write code that communicates over a network, without understanding the hardware
and software technologies that are used to transfer data from one application to another.
However, knowledge of the underlying network system allows a programmer to write better
code.
1.5 What is packet‐switching, and why is packet switching relevant to the Internet? -
ANS-Answer: Packet switching divides data into small blocks, called packets, and includes an
identification of the intended recipient in each packet. Packet switching changed networking in a
fundamental way, and provided the basis for the modern Internet. Packet switching allows
multiple senders to transmit data over a shared network.
1.8 What is a communication protocol? Conceptually, what two aspects of communication does
a protocol specify? - ANS-Answer: A communication protocol refer to a specification for network
communication. Major aspects of a protocol are syntax (format) and semantics (meaning) of the
protocol.
1.9 What is a protocol suite, and what is the advantage of a suite? - ANS-Answer: protocols are
designed in complete, cooperative sets called suites or families, instead of creating each
protocol in isolation. Each protocol in a suite handles one aspect of communication; together,
the protocols in a suite cover all aspects of communication. The entire suite is designed to allow
the protocols to work together efficiently.
1.11 List the layers in the TCP/IP model, and give a brief explanation of each. - ANS-Answer:
The TCP/IP consists of 5 layers. The layers and their short explanation is as follows: Layer 1:
Physical: Protocols in the Physical layer specify details about the underlying transmission
medium and the associated hardware. Layer 2: Network Interface Protocols in the Network
Interface layer specify details about communication between higher layers of protocols and the
underlying network. Layer 3: Internet: Protocols in the Internet layer form the fundamental basis
for the Internet. Layer 3 protocols specify communication between two computers across the
Internet Layer 4: Transport: Protocols in the Transport layer provide for communication from an
application program on one computer to an application program on another. Layer 5:
Application: Protocols in the top layer of the TCP/IP stack specify how a pair o applications
interact when they communicate.
1.12 Explain how headers are added and removed as data passes through a layered model. -
ANS-Answer: each layer on the sending computer prepends extra information onto the packet;
, the corresponding protocol layer on the receiving computer removes and uses the extra
information.
1.14 Give a brief explain of the layers in the ISO Open System Interconnection model. -
ANS-Answer: ISO OSI model consists of 7 layers, namely:
Layer 7: Application Layer 6: Presentation Layer 5: Session Layer 4: Transport Layer 3:
Network Layer 2: Data Link Layer 1: Physical Reader is expected to find out short explanation of
each layer
3.1 What are the two basic communication paradigms used in the Internet? - ANS-Answer:
There are various approaches, but according to textbook, we can specify them as Stream
Paradigm and Message Paradigm.
3.2 Give six characteristics of Internet stream communication. - ANS-Answer: Characteristics of
Internet stream communication can be listed as follows: Connection‐oriented 1‐to‐1
communication Sequence of individual bytes Arbitrary length transfer Used by most applications
Built on TCP protocol
3.3 Give six characteristics of Internet message communication. - ANS-Answer: Characteristics
of Internet message communication can be listed as follows: Connectionless Many‐to‐many
communication Sequence of individual messages Each message limited to 64 Kbytes Used for
multimedia applications Built on UDP protocol
3.5 If a sender wants to have copies of each data block being sent to three recipients, which
paradigm should the sender choose? - ANS-Answer: The message paradigm is suitable for
such transfer, since it allows many‐to‐many communication
3.7 Give the general algorithm that a connection‐oriented system uses. - ANS-Answer: The
interaction between two connection‐oriented parties can be summarized as: Setting‐up
connection between two parties Exchange information Terminate the connection
3.8 When two applications communicate over the Internet, which one is the server? -
ANS-Answer: The application that waits for some other applications to contact is called server,
and the application that contact other one is called client.
3.10 What is the difference between a server and a server‐class computer? - ANS-Answer: The
server term refers to a program that waits passively for communication, and not to the computer
on which it executes. However, when a computer is dedicated to running one or more server
programs, the computer itself is sometimes called a server. Hardware vendors contribute to the
confusion because they classify computers that have fast CPUs, large memories, and powerful
operating systems as server machines.
3.11 Can data flow from a client to a server? Explain. - ANS-Answer: Yes, data may flow in both
directions (client server and server client).
1.3 According to the text, is it possible to develop Internet applications without understanding
the architecture of the Internet and the technologies? Support your answer. - ANS-Answer: Yes,
possible to write code that communicates over a network, without understanding the hardware
and software technologies that are used to transfer data from one application to another.
However, knowledge of the underlying network system allows a programmer to write better
code.
1.5 What is packet‐switching, and why is packet switching relevant to the Internet? -
ANS-Answer: Packet switching divides data into small blocks, called packets, and includes an
identification of the intended recipient in each packet. Packet switching changed networking in a
fundamental way, and provided the basis for the modern Internet. Packet switching allows
multiple senders to transmit data over a shared network.
1.8 What is a communication protocol? Conceptually, what two aspects of communication does
a protocol specify? - ANS-Answer: A communication protocol refer to a specification for network
communication. Major aspects of a protocol are syntax (format) and semantics (meaning) of the
protocol.
1.9 What is a protocol suite, and what is the advantage of a suite? - ANS-Answer: protocols are
designed in complete, cooperative sets called suites or families, instead of creating each
protocol in isolation. Each protocol in a suite handles one aspect of communication; together,
the protocols in a suite cover all aspects of communication. The entire suite is designed to allow
the protocols to work together efficiently.
1.11 List the layers in the TCP/IP model, and give a brief explanation of each. - ANS-Answer:
The TCP/IP consists of 5 layers. The layers and their short explanation is as follows: Layer 1:
Physical: Protocols in the Physical layer specify details about the underlying transmission
medium and the associated hardware. Layer 2: Network Interface Protocols in the Network
Interface layer specify details about communication between higher layers of protocols and the
underlying network. Layer 3: Internet: Protocols in the Internet layer form the fundamental basis
for the Internet. Layer 3 protocols specify communication between two computers across the
Internet Layer 4: Transport: Protocols in the Transport layer provide for communication from an
application program on one computer to an application program on another. Layer 5:
Application: Protocols in the top layer of the TCP/IP stack specify how a pair o applications
interact when they communicate.
1.12 Explain how headers are added and removed as data passes through a layered model. -
ANS-Answer: each layer on the sending computer prepends extra information onto the packet;
, the corresponding protocol layer on the receiving computer removes and uses the extra
information.
1.14 Give a brief explain of the layers in the ISO Open System Interconnection model. -
ANS-Answer: ISO OSI model consists of 7 layers, namely:
Layer 7: Application Layer 6: Presentation Layer 5: Session Layer 4: Transport Layer 3:
Network Layer 2: Data Link Layer 1: Physical Reader is expected to find out short explanation of
each layer
3.1 What are the two basic communication paradigms used in the Internet? - ANS-Answer:
There are various approaches, but according to textbook, we can specify them as Stream
Paradigm and Message Paradigm.
3.2 Give six characteristics of Internet stream communication. - ANS-Answer: Characteristics of
Internet stream communication can be listed as follows: Connection‐oriented 1‐to‐1
communication Sequence of individual bytes Arbitrary length transfer Used by most applications
Built on TCP protocol
3.3 Give six characteristics of Internet message communication. - ANS-Answer: Characteristics
of Internet message communication can be listed as follows: Connectionless Many‐to‐many
communication Sequence of individual messages Each message limited to 64 Kbytes Used for
multimedia applications Built on UDP protocol
3.5 If a sender wants to have copies of each data block being sent to three recipients, which
paradigm should the sender choose? - ANS-Answer: The message paradigm is suitable for
such transfer, since it allows many‐to‐many communication
3.7 Give the general algorithm that a connection‐oriented system uses. - ANS-Answer: The
interaction between two connection‐oriented parties can be summarized as: Setting‐up
connection between two parties Exchange information Terminate the connection
3.8 When two applications communicate over the Internet, which one is the server? -
ANS-Answer: The application that waits for some other applications to contact is called server,
and the application that contact other one is called client.
3.10 What is the difference between a server and a server‐class computer? - ANS-Answer: The
server term refers to a program that waits passively for communication, and not to the computer
on which it executes. However, when a computer is dedicated to running one or more server
programs, the computer itself is sometimes called a server. Hardware vendors contribute to the
confusion because they classify computers that have fast CPUs, large memories, and powerful
operating systems as server machines.
3.11 Can data flow from a client to a server? Explain. - ANS-Answer: Yes, data may flow in both
directions (client server and server client).
