ASHIR MUBEEN

SAHIRoll No. B13001

TOPOLOGYTopology (from the Greek τόπος, "place", and λόγος, "study") is the mathematical study of shapes and topological spaces.The term topology was introduced by Johann Benedict Listing in the 19th century. By the middle of the 20th century, topology had become a major branch of mathematics.

NETWORK TOPOLOGY• Network topology is the arrangement of the various

elements (links, nodes, etc.) of a network.

TYPES:Can be depicted Physically or Logically.

Physical TopologyPhysical topology is the placement of the various components of a network, including device location and cable installation.How devices are connected to the network through the actual cables that transmit data, or the physical structure of the network, is called the physical topology. This refers to the layout of cabling, the locations of nodes, and the interconnections between the nodes and the cabling. Physical topology defines how the systems are physically connected.

BUS Topology

• In LAN where bus topology is used, each node is connected to a single cable, known as backbone or bus cable.

• A signal from the source travels in both directions to all nodes connected on the bus cable until it finds the intended recipient.

• If the node address does not match the intended address for the data, the node ignores the data. Alternatively, if the data matches the node address, the data is accepted.

Advantage: The bus topology consists of only one main cable, it is inexpensive to implement when compared to other topologies.

Drawback: In a bus topology, only one cable is utilized, it can be the single point of failure.

STAR Topology•In Star topology every node is connected to central node called hub or switch. •The switch is the server and the peripherals are the clients.• The network does not necessarily have to resemble a star to be classified as a star network, but all of the nodes on the network must be connected to one central device. •All traffic that traverses the network passes through the central hub. •The hub acts as a signal repeater.

Advantage: An advantage of the star topology is the simplicity of adding additional nodes. The star topology is considered the easiest topology to design and implement.Disadvantage: The primary disadvantage of the star topology is that the hub represents a single point of failure.

RING Topology

•A network topology that is set up in a circular fashion in which data travels around the ring in one direction and each device on the ring acts as a repeater to keep the signal strong as it travels. •Each device incorporates a receiver for the incoming signal and a transmitter to send the data on to the next device in the ring.• When a device sends data, it must travel through each device on the ring until it reaches its destination.•Token is used for data transfer.Advantage: In a ring topology, there is no server computer present; all nodes work as a server and repeat the signal.Drawback: The disadvantage of this topology is that if one node stops working, the entire network is affected or stops working.

NETWORK TECHNOLOGIESHUBA hub is a device that connects a number of computers together to make a LAN.

The typical use of a hub is at the centre of a star network - the hub has cables plugged into it from each computer.

A hub is a ‘dumb’ device: if it receives a message, it sends it to every computer on the network. This means that hub-based networks are not very secure - everyone can listen in to communications.

SWITCHA switch, like a hub, is a device that connects a number of computers together to make a LAN. The typical use of a switch is at the centre of a star network - the switch has cables plugged into it from each computer.

• A switch is a more ‘intelligent’ device than a hub: if it receives a message, it checks who it is addressed to, and only sends it to that specific computer.

• Networks that use switches are more secure than those that use hubs, but also a little more expensive.

ROUTERA router is a network device that connects together two or more networks.A common use of a router is to join a home or business network (LAN) to the Internet (WAN).The router will typically have the Internet cable plugged into it, as well as a cable, or cables to computers on the LAN.

Alternatively, the LAN connection might be wireless (Wi-Fi), making the device a wireless router. (A wireless router is actually a router and wireless switch combined…)

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