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1.What is Network Topology?

-is the physical interconnections of the elements (links,nodes,etc.,)
of a computer network. A local area network (LAN)is one example
of networkthat exhibits both a physical topolgy and a logic topology.
Any given node in the LAND as one or more links to one or more
other nodes in the network and the mapping of this links and nodes
in a graph results in a geometrical shape that may be used to describe
the physical topologyof the network. Likewise, the mapping of the
dataflows between the nodes in the network determines the logic
tropology of the network. The physical and logic tropologies may
or may not be identical in any particular network.
-Any particular network topology is determined only by the graphical
mapping of the configuration of physical and/or logic connections
between nodes. The study of Network Topology uses of graph theory.
Distances between nodes physical interconnections, transmission rates,
and/or signal types may differ in two networks and yet thier topologies
may be identical.

2. Examples of Network Topology, their Definition and post example picture.

-Tree Topology is a combination of the BUS and STAR Topology. The tree like structure allows you to have many servers on the network and you can branch out the networks in many ways. This is particularly helpful for colleges, universities and schools so the each of the branches can identify the relevant systems in thier own network and yet connect to the big network in some way.

-Bus (Line) nodes are connected to a main (bus) cable. If data is being sent between nodes then other nodes cannot transmit. If too many nodes are connected then the transfer of data slows dramatically as the nodes have to wait longer for the bus to be clear.

-A Fully connected network is a mesh network in which each of nodes is connected to each other. A fully connected network doesn't need to use switching nor broadcasting.

-Star networks are one of the most common computer network topologies. In its simplest from, a star network consits of one central switch, hub or computer which acts as a conduit to transmit messages.

-Mesh network differ from other networks in that the component parts can all connect to each other via multiple hops, and they generally are not mobile. Mesh network can be seen as one type of adhoc network.

-A Ring network is a network topology in which each node connects to excatly two other nodes, forming a sinlge continous pathway for signals through each nodes - a ring. Dat travels from node to node, with each node along the way handling every packet.

3. What is OSI layer?

Short for Open System Interconnection, an ISO standard for worldwide communacations that defines a networking framework for implementing protocols in seven layers. Control is passed from one layer to the next, starting at the application layer in one station, proceeding to the bottom layer, over the channel to the next station and back up the heirarchy.

3. Example of OSI Layer, thier definition in order

1. PHYSICAL LAYER- consits of the basic hardware transmission technologies of a network . It is a fundamental layer underlying the logical data structures of the higer level functions of a network.
2. DATA LINK LAYER- is concerned with local delivery of frames between devices of the same LAN.
3. NETWORK LAYER- provides the funtionaland procedural means of transferring variable lenght data sequences from a source to a destination host via one or more networks while maintaining the quality of service and error control functions.
4. TRANSPORT LAYER- is a group of methods and protocols within a layered architecture of network components within which it is responsible for encapsulating application data blocks into data units (datagrams, segments) suitable for transferto the network infrastructure for transmission to the destination host, or managing the reverse transaction by abstracting network data grams and delivering thier payload to an application.
5. SESSION LAYER- provides the mechanism for opening, closing and managing a session between end-user application procesess, i.e. a semi-permanent dailague.
6. PRESENTATION LAYER- is responsible for the delivery and formatting of information to the apllication layer for the further processing or display.
7. APPLICATION LAYER- is a term used in categorizing protocols and methods in archetictural models of computer networking. Both the OSI model and the Internet Protocol Suite (TCPI/IP) contain an application layer.

5.What is Networking?

-In the world of computers, Networking is the practice of linking two or more computing devices together for the purpose of sharing data. Network are build with a mix of computer hardware and computer software.