What are advantages and disadvantages of a layered architecture? - ✔✔Each protocol layer offers
different services. Some advantages are scalability,
... [Show More] 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? - ✔✔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 the five-layer model combines the
application, presentation, and 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.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. - ✔✔Application layer: Service, Interface, Protocol. Ex: Turn on
your smartphone and look at the list of apps. (HTTP, SMTP, FTP, DNS)
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 [Show Less]