Hi, and welcome to Section two Network Fundamentals.
In this video, we are going to see an introduction about network fundamentals.
Computer networks are a large number of separate but interconnected computers.
They are a collection of autonomous computers interconnected by a single
technology in many sizes, shapes, and forms.
There is a separation between computer networks and distributed systems.
Distribution system is a collection of independent computers.
They appear to their users as a single current system,
a layer of software on top of the operating system called middleware
that is responsible for dis implementation.
Another definition about Disting system is that is a software system
built on top of a network. In computer networks,
this model don't exist and the users are exposed to the actual
machines. The configuration of a machine in a network.
Computers as harder and different operation systems are fully visible
to the users.
The distinction between a network in a distribution system lies with the
software that gives a high degree of current stiffness and transparency.
Networks are useful to share fiscal resource and share
information in general. For small companies,
all the computers could be in a single office, in a single room.
For large companies,
the computers and employees may be distributed over many offices
and in and in many ss. In networks,
we have a concept called V P N.
That's mean V 12 private networks that may be used to join
into one xtend network. In networks, we have the client server model.
It's when, uh, means when data are stored on one computer, call a server,
and the client with which the user trying to access
this data remotely.
Its model works in a flow of requests and responses.
Two type of transmissions technology are used,
broadcast links and point-to-point links. Point-to-point links,
connect individual pairs to machines to go from the source to the
destination. On a network made up of point to point links,
short messenger call packets in a certain context,
may have to first visit one or more.
Intermediate machines broadcast.
Use a channel that is shared by all the machines on the network
packets sent by any machine.
I receive it by all the other orders machines. Uh,
alternative standard for classification network is by scale.
Distance is important as a classification metric because different technologies
are used. Different scale, distance of a meter, uh, spaces,
square meter and 10 meters is
a space of a room. The network, call it personal area network.
A addition of a hundred meters,
it's like a building or a one kilometers. It's like a a university campus.
The,
the network is called local area network or land in one
kilometer, 10 kilometers or a hundred kilometers.
The size of Syrian countries is called metropolitan area network
and a distance of a thousand kilometers to more than
10,000 kilometers. The scale of a space, a continent or planet,
the name of the networks,
we can call it the wide area network for continent and in the
scale of the planet. The worldwide is call it the internet Network.
Communications are defined by protocols. To communicate between systems,
we use a set of common language called protocols.
A logical grouping of protocols that work together is called a protocol stack.
Protocols work allowing us to define how packet should be routed,
how to initiate a connection,
and how to acknowledge the recipient of data.
Many protocols address the following issues, connection, initiation,
negotiation of connection characteristics, data formatting, error,
detecting and correction, connection, termination,
network hardware. We can define network hardware in three type of hardwares,
hubs, switches, and routers. In hubs,
it can generate a law of unnecessary network traffic.
They are capable of operating only in half two blocks mode.
They cannot send and receive data at the same time.
It's a repeating device that operates on a physical layer.
It takes packets sent from one port and transmissions or
repeats then to every port on the device and it's up to the receiving
device to accept or reject each packet.
Switches is a full duplex devices.
It's designed to repeat packets.
It sends data to only the computer for which the data is intended.
It's able to communicate directly with the specific devices.
Switches must be able to uniquely identify devices based on their
MAC addresses,
which mean that they must operate on the data link Layer routers,
it's an advanced network.
Devices meet a much high level of functionality that then a switch on our
ah hub.
It operates at layer three where they are responsible for forwarding packets
between two or more networks routing.
This mean the process used by routers to redirect the flow of traffic
among networks.
It's used layer three addresses like IP to uniquely
identify devices on network. In traffic classifications,
we can define the traffic in three types of classification, broadcast,
broadcast and uncast.
Broadcast traffic is a packet that's sent to all ports on a network
segment.
Regardless of whether a given port is a hub or switch,
there are layer two O and layer three forms of broadcast traffic,
mood cast traffic.
It's a transmission of packet from single source to multiple destinations
simultaneously.
The goal of multicasting is to use a little bandwidth as possible.
The exact handling of multicast traffic is highly depend on its implementation.
In individual protocols,
unicast traffic unicast packet is transmitted from one computer directly to
another.
The details of how newcast function are depend on the protocol that use it.
In this video, we saw an introduction about network fundamentals.
Next, we saw a classification of networks by scale.
And finally we take a look in network protocols,
other and traffic classification.
The next session we'll start introduction to wire sharp.