CS6250 COMPUTER NETWORKS EXAM 1
EXAMPREP COMPREHENSIVE QUESTIONS
AND VERIFIED RESPONSES GUARANTEED
TO PASS
⩥ Layered Architecture.
Answer: Each protocol layer offers different services.
⩥ Layered Architecture Advantages.
Answer: - Scalability,
- Flexibility
- Ease of adding / removing components making it easier for cost-
effective implementations.
⩥ Layered Architecture Disadvantages.
Answer: - 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
- Overhead in message headers caused by abstraction barriers between
layers.
,⩥ OSI and Five-Layered Internet model Similarities.
Answer: Many of the layers are the same
⩥ OSI and Five-Layered Internet model Differences.
Answer: - Three of the layers are combined in the 5-layered model.
- Specifically the five-layer model combines the
- Application
- Presentation
- Session layers
from the OSI model into a single Application layer.
⩥ What are sockets?.
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.
- ."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: - Application layer: Service, Interface, Protocol.
- Presentation layer: Plays intermediate role of formatting the
information received from the layer below and delivering it to the
application layer.
- Session layer: Responsible for the mechanism that manages the
different transport streams that belong to the same session between end-
user and application process.
- Transport layer: Responsible for the end-to-end communication
between end hosts.
Network layer: This layer is responsible for moving the packet of
information, called a datagram, from one host to another.
- Data Link layer: Responsible for moving the frames from one node
(host or router) to the next node.
, - Physical layer: This layer is the actual hardware responsible to transfer
bits within a frame between two nodes c
⩥ OSI Model Application Layer.
Answer: - Service, Interface, Protocol.
Ex: Turn on your smartphone and look at the list of apps. (HTTP, SMTP,
FTP, DNS)
⩥ OSI Model Presentation Layer.
Answer: - 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.
⩥ OSI Model Session Layer.
Answer: - 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.
⩥ OSI Model Network Layer.
EXAMPREP COMPREHENSIVE QUESTIONS
AND VERIFIED RESPONSES GUARANTEED
TO PASS
⩥ Layered Architecture.
Answer: Each protocol layer offers different services.
⩥ Layered Architecture Advantages.
Answer: - Scalability,
- Flexibility
- Ease of adding / removing components making it easier for cost-
effective implementations.
⩥ Layered Architecture Disadvantages.
Answer: - 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
- Overhead in message headers caused by abstraction barriers between
layers.
,⩥ OSI and Five-Layered Internet model Similarities.
Answer: Many of the layers are the same
⩥ OSI and Five-Layered Internet model Differences.
Answer: - Three of the layers are combined in the 5-layered model.
- Specifically the five-layer model combines the
- Application
- Presentation
- Session layers
from the OSI model into a single Application layer.
⩥ What are sockets?.
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.
- ."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: - Application layer: Service, Interface, Protocol.
- Presentation layer: Plays intermediate role of formatting the
information received from the layer below and delivering it to the
application layer.
- Session layer: Responsible for the mechanism that manages the
different transport streams that belong to the same session between end-
user and application process.
- Transport layer: Responsible for the end-to-end communication
between end hosts.
Network layer: This layer is responsible for moving the packet of
information, called a datagram, from one host to another.
- Data Link layer: Responsible for moving the frames from one node
(host or router) to the next node.
, - Physical layer: This layer is the actual hardware responsible to transfer
bits within a frame between two nodes c
⩥ OSI Model Application Layer.
Answer: - Service, Interface, Protocol.
Ex: Turn on your smartphone and look at the list of apps. (HTTP, SMTP,
FTP, DNS)
⩥ OSI Model Presentation Layer.
Answer: - 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.
⩥ OSI Model Session Layer.
Answer: - 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.
⩥ OSI Model Network Layer.
