Define network architecture including topologies (star, tree, and mesh) and strategies (client/server and peer-to-peer).

Network Architecture : 

It is the design of a communications system, which includes the backbones, routers, switches, wireless access points, access methods and protocols used. 

Types of Network Architecture :

1. Peer-to-Peer Architecture
2. Client/Server Architecture

1. Peer-to-Peer Architecture : 

In a peer-to-peer network, tasks are allocated to every device on the network. Furthermore, there is no real hierarchy in this network, all computers are considered equal and all have the same abilities to use the resources available on this network. Instead of having a central server which would act as the shared drive, each computer thats connected to this network would act as the server for the files stored on it.

2. Client/Server Architecture : 

Network Topology :

A network topology is the pattern in which nodes (i.e., computers, printers, routers or other devices) are connected to a local area network (LAN) or other network via links (e.g., twisted pair copper wire cable or optical fiber cable). There are four principal topologies used in LANs: bus, ring, star and mesh.

1. Star Topology :

Star Topology probably the most common topology. In star network, all nodes are connected to a device called hub and communicate through it. Data packets travel through the hub and are sent to attached nodes,eventually reaching their destinations. Some hubs - known as intelligent hubs- can monitor traffic and help prevent collisions.

Advantages of Star Topology :In star topology a broken connection between a node and the hub does not affect the rest of the network

Disadvantage of Star Topology: If the hub is lost, however all the nodes connected to that hub are unable to communicate.

2. Tree Topology :

Tree Topology or Hierarchical Topology is the combination of the characteristics of a star topology and a bus topology. In this topology, a star -configured workstation in a group are connected to cable which acts as a linear bus backbone. The tree bus can connect only with the hub device directly. It has a central hub acts as a root of a tree of a network device. It has a central root node which is connected to one or more nodes present in the lower hierarchical topology. 

Advantage of Tree Topology Point to point wiring for every segment is the main advantage. It is also supported by most of the hardware and software vendors.

Disadvantage Of Tree Topology The type of the cabling limits the overall length of each segment. When the backbone line breaks, it leads to the breakdown of the complete segment. Tree topology becomes more difficulty to configure and wire comparision to the other topologies.

3. Mesh Topology :

Mesh Topology is the least used network topology and the most expensive to implement. In mesh environment, a cable runs from every computer to every other computer. If you have four computers, you must have six cables—three coming from each computer to the other computers. 

Formula: (n(n-1))/2

Advantage Of Mesh Topology The big advantage to this arrangement is that data can never fail to be delivered. If any one connection goes down, there are other ways to route the data to its destination.

Disadvantage of Mesh Topology Most expensive network as large amount of cabling is required. Expensive hardware and software is needed to implement this network.