CS6250 Computer Networks Exam 1
Review 2025/2026 Exam Questions
Marking Scheme New Update | A+ Rated
What are advantages and disadvantages of a layered architecture? - 🧠
ANSWER ✔✔- ANSWER ✅: Each protocol layer offers different services.
Some advantages are scalability, flexibility, and ease of adding / removing
components making it easier for cost-effective implementations.
Disadvantages include: some layers functionality depends on the
information from the other layer and violates the goal of layer separation;
one layer may duplicate lower layer functionalities; overhead both in
computation and in message headers caused by abstraction barriers
between layers.
What are the differences and similarities of the OSI model and five-layered
Internet model? - 🧠 ANSWER ✔✔- ANSWER ✅The OSI model and the 5-
layered Internet Model have many of the same layers, with the difference
being three of the layers are combined in the 5-layered model. Specifically
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,the five-layer model combines the application, presentation, and session
layers from the OSI model into a single application layer.
What are sockets? - 🧠 ANSWER ✔✔- ANSWER ✅A network socket is a
software structure within a network node of a computer network that serves
as an endpoint for sending and receiving data across the network. The
structure and properties of a socket are defined by an application
programming interface (API) for the networking architecture. Sockets are
created only during the lifetime of a process of an application running in the
node.https://en.wikipedia.org/wiki/Network_socket."A process sends
messages into, and receives messages from, the network through a
software interface called a socket. Let's consider an analogy to help us
understand processes and sockets. A process is analogous to a house and
its socket is analogous to its door....a socket is the interface between the
application layer and the transport layer within a host." - Kurose and Ross,
2.1
Describe each layer of the OSI model. - 🧠 ANSWER ✔✔- ANSWER
✅Application layer: Service, Interface, Protocol. Ex: Turn on your
smartphone and look at the list of apps. (HTTP, SMTP, FTP, DNS)
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,Presentation layer: Plays intermediate role of formatting the information
received from the layer below and delivering it to the application layer. Ex:
converting big endian to little endian.
Session layer: Responsible for the mechanism that manages the different
transport streams that belong to the same session between end-user and
application process. Ex: teleconference app, it is responsible for tying
together audio and video streaming.
Transport layer: Responsible for the end-to-end communication between
end hosts. 2 transport protocols, TCP and UDP. TCP includes a
connection-oriented service to the applications that are running on the layer
above, guaranteed delivery of the application-layer messages, flow control,
and congestion control mechanism. UDP provides a connectionless, best-
effort service to the applications that are running in the layer above without
reliability, flow, or congestion control. In this layer the packet is called a
segment.
Network layer: This layer is responsible for moving the packet of
information, called a datagram, from one host to another. The network layer
is responsible for delivering the datagram to the Transport layer on the
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, destination host. In this layer there are the IP Protocol and the routing
tables.
Data Link layer: Packets are referred to as frames. Examples include:
ethernet, ppp, wifi. Responsible for moving the frames from one node (host
or router) to the next node. Services offered by the data link layer protocol
include reliable delivery (transmission of the data from one transmitting
node, across one link, to the receiving node.
Physical layer: This layer is the actual hardware responsible to transfer bits
within a frame between t
Provide examples of popular protocols at each layer of the five-layered
Internet model. - 🧠 ANSWER ✔✔- ANSWER ✅Application: NFS, DNS,
SNMP, ftp, rcp, telnet, HTTP
Transport: TCP, UDP
Internet: IP, ARP, ICMP
Data Link: PPP, IEEE 802.2, Ethernet
Physical Network: Token Ring, RS-232
What is encapsulation, and how is it used in a layered model? - 🧠 ANSWER
✔✔- ANSWER ✅Encapsulation is when data (called a header) is
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Review 2025/2026 Exam Questions
Marking Scheme New Update | A+ Rated
What are advantages and disadvantages of a layered architecture? - 🧠
ANSWER ✔✔- ANSWER ✅: Each protocol layer offers different services.
Some advantages are scalability, flexibility, and ease of adding / removing
components making it easier for cost-effective implementations.
Disadvantages include: some layers functionality depends on the
information from the other layer and violates the goal of layer separation;
one layer may duplicate lower layer functionalities; overhead both in
computation and in message headers caused by abstraction barriers
between layers.
What are the differences and similarities of the OSI model and five-layered
Internet model? - 🧠 ANSWER ✔✔- ANSWER ✅The OSI model and the 5-
layered Internet Model have many of the same layers, with the difference
being three of the layers are combined in the 5-layered model. Specifically
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER:
619652435. TERMS OF USE. PRIVACY STATEMENT. ALL RIGHTS RESERVED 1
,the five-layer model combines the application, presentation, and session
layers from the OSI model into a single application layer.
What are sockets? - 🧠 ANSWER ✔✔- ANSWER ✅A network socket is a
software structure within a network node of a computer network that serves
as an endpoint for sending and receiving data across the network. The
structure and properties of a socket are defined by an application
programming interface (API) for the networking architecture. Sockets are
created only during the lifetime of a process of an application running in the
node.https://en.wikipedia.org/wiki/Network_socket."A process sends
messages into, and receives messages from, the network through a
software interface called a socket. Let's consider an analogy to help us
understand processes and sockets. A process is analogous to a house and
its socket is analogous to its door....a socket is the interface between the
application layer and the transport layer within a host." - Kurose and Ross,
2.1
Describe each layer of the OSI model. - 🧠 ANSWER ✔✔- ANSWER
✅Application layer: Service, Interface, Protocol. Ex: Turn on your
smartphone and look at the list of apps. (HTTP, SMTP, FTP, DNS)
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619652435. TERMS OF USE. PRIVACY STATEMENT. ALL RIGHTS RESERVED 2
,Presentation layer: Plays intermediate role of formatting the information
received from the layer below and delivering it to the application layer. Ex:
converting big endian to little endian.
Session layer: Responsible for the mechanism that manages the different
transport streams that belong to the same session between end-user and
application process. Ex: teleconference app, it is responsible for tying
together audio and video streaming.
Transport layer: Responsible for the end-to-end communication between
end hosts. 2 transport protocols, TCP and UDP. TCP includes a
connection-oriented service to the applications that are running on the layer
above, guaranteed delivery of the application-layer messages, flow control,
and congestion control mechanism. UDP provides a connectionless, best-
effort service to the applications that are running in the layer above without
reliability, flow, or congestion control. In this layer the packet is called a
segment.
Network layer: This layer is responsible for moving the packet of
information, called a datagram, from one host to another. The network layer
is responsible for delivering the datagram to the Transport layer on the
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER:
619652435. TERMS OF USE. PRIVACY STATEMENT. ALL RIGHTS RESERVED 3
, destination host. In this layer there are the IP Protocol and the routing
tables.
Data Link layer: Packets are referred to as frames. Examples include:
ethernet, ppp, wifi. Responsible for moving the frames from one node (host
or router) to the next node. Services offered by the data link layer protocol
include reliable delivery (transmission of the data from one transmitting
node, across one link, to the receiving node.
Physical layer: This layer is the actual hardware responsible to transfer bits
within a frame between t
Provide examples of popular protocols at each layer of the five-layered
Internet model. - 🧠 ANSWER ✔✔- ANSWER ✅Application: NFS, DNS,
SNMP, ftp, rcp, telnet, HTTP
Transport: TCP, UDP
Internet: IP, ARP, ICMP
Data Link: PPP, IEEE 802.2, Ethernet
Physical Network: Token Ring, RS-232
What is encapsulation, and how is it used in a layered model? - 🧠 ANSWER
✔✔- ANSWER ✅Encapsulation is when data (called a header) is
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER:
619652435. TERMS OF USE. PRIVACY STATEMENT. ALL RIGHTS RESERVED 4
