CS6250 COMPUTER NETWORKS EXAM 1 | QUESTIONS AND
ANSWERS | VERIFIED ANSWERS GRADED A+ | LATEST EXAM
UPDATE
What are advantages and disadvantages of a layered architecture? - CORRECT
ANSWER - Each protocol layer offers different services.
Layered Architecture - CORRECT ANSWER - Each protocol layer offers
different services.
Layered Architecture Advantages - CORRECT ANSWER - - Scalability,
- Flexibility
- Ease of adding / removing components making it easier for cost-effective
implementations.
Layered Architecture Disadvantages - CORRECT 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 - CORRECT ANSWER -
Many of the layers are the same
OSI and Five-Layered Internet model Differences - CORRECT 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? - CORRECT 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. - CORRECT 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 - CORRECT ANSWER - - Service, Interface,
Protocol.
Ex: Turn on your smartphone and look at the list of apps. (HTTP, SMTP, FTP,
DNS)
OSI Model Presentation Layer - CORRECT 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 - CORRECT 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 - CORRECT ANSWER - - 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 - CORRECT ANSWER - - 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.
- 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.
OSI Model Data Link Layer - CORRECT ANSWER - - Packets are referred to
as frames.
- Examples include:
- ethernet,
- ppp,
- wifi.
ANSWERS | VERIFIED ANSWERS GRADED A+ | LATEST EXAM
UPDATE
What are advantages and disadvantages of a layered architecture? - CORRECT
ANSWER - Each protocol layer offers different services.
Layered Architecture - CORRECT ANSWER - Each protocol layer offers
different services.
Layered Architecture Advantages - CORRECT ANSWER - - Scalability,
- Flexibility
- Ease of adding / removing components making it easier for cost-effective
implementations.
Layered Architecture Disadvantages - CORRECT 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 - CORRECT ANSWER -
Many of the layers are the same
OSI and Five-Layered Internet model Differences - CORRECT 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? - CORRECT 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. - CORRECT 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 - CORRECT ANSWER - - Service, Interface,
Protocol.
Ex: Turn on your smartphone and look at the list of apps. (HTTP, SMTP, FTP,
DNS)
OSI Model Presentation Layer - CORRECT 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 - CORRECT 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 - CORRECT ANSWER - - 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 - CORRECT ANSWER - - 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.
- 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.
OSI Model Data Link Layer - CORRECT ANSWER - - Packets are referred to
as frames.
- Examples include:
- ethernet,
- ppp,
- wifi.
