CS6250 COMPUTER NETWORK EXAM 1 |
Complete Study Guide with Questions and
Verified Answers | 100% Correct | Graded
A+
‣ Layered Architecture Advantages -✓✓- Scalability,
- Flexibility
- Ease of adding / removing components making it easier for cost-
effective implementations.
‣ Layered Architecture Disadvantages -✓✓- 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 -✓✓Many of the
layers are the same
‣ OSI and Five-Layered Internet model Differences -✓✓- 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? -✓✓- 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. -✓✓- 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 -✓✓- Service, Interface, Protocol.
Ex: Turn on your smartphone and look at the list of apps. (HTTP,
SMTP, FTP, DNS)
‣ OSI Model 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.
‣ OSI Model 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.
‣ OSI Model Network Layer -✓✓- This layer is responsible for moving
the packet of information, called a datagram, from one host to another.
- Responsible for delivering the datagram to the Transport layer on the
destination host.
- In this layer there are the IP Protocol and the routing tables.
‣ OSI Model Transport Layer -✓✓- Responsible for the end-to-end
communication between end hosts.
- 2 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.
Complete Study Guide with Questions and
Verified Answers | 100% Correct | Graded
A+
‣ Layered Architecture Advantages -✓✓- Scalability,
- Flexibility
- Ease of adding / removing components making it easier for cost-
effective implementations.
‣ Layered Architecture Disadvantages -✓✓- 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 -✓✓Many of the
layers are the same
‣ OSI and Five-Layered Internet model Differences -✓✓- 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? -✓✓- 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. -✓✓- 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 -✓✓- Service, Interface, Protocol.
Ex: Turn on your smartphone and look at the list of apps. (HTTP,
SMTP, FTP, DNS)
‣ OSI Model 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.
‣ OSI Model 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.
‣ OSI Model Network Layer -✓✓- This layer is responsible for moving
the packet of information, called a datagram, from one host to another.
- Responsible for delivering the datagram to the Transport layer on the
destination host.
- In this layer there are the IP Protocol and the routing tables.
‣ OSI Model Transport Layer -✓✓- Responsible for the end-to-end
communication between end hosts.
- 2 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.
