Networks Lesson 7

types of logical topology

1. broadcast topology 2. token passing

types of rings

1. single rings 2. dual rings

disadvantages of star

A central connection point might be desirable for security or restricted access, but this is also a main disadvantage of a star topology. If the central device fails, the whole network becomes disconnected.

heirarchial

A hierarchical topology is created similar to an extended-star topology. • The primary difference is that it does not use a central node. • It uses a trunk node from which it branches to other nodes. • Two types of tree topologies exist: • the binary tree (each node splits into two links) and • the backbone tree (a backbone trunk has branch nodes with links hanging from it).

network topology

A network topology defines how computers, printers, network devices, and other devices are connected. A network topology describes the layout of the wire and devices as well as the paths used by data transmissions.

logical topology

A network's logical topology describes how the hosts communicate across the medium.

advantages of star

Because each host is connected to the central device with its own cable, when that cable has a problem, only that host is affected; the rest of the network remains operational.

ring topology

Hosts are connected in the form of a ring or circle. • The ring topology has no beginning or end that needs to be terminated. • Data is transmitted by way of a frame that travels around the ring, stopping at each node. • If a node wants to transmit data, it is permitted to add that data as well as the destination address to the frame. • The frame then continues around the ring until it finds the destination node, which takes the data out of the frame.

dual ring

In a dual ring, two rings allow data to be sent in both directions. This setup creates redundancy (fault tolerance), meaning that if one ring fails, data can be transmitted on the other ring. Also, if both rings fail, a "wrap" at the fault can heal the topology back into a ring.

partial mesh topology

In a partial-mesh topology, at least one device maintains multiple connections to others without being fully meshed.

single ring

In a single ring, all the devices on the network share a single cable, and the data travels in one direction only. Each device waits its turn to send data over the network. Most single-ring topologies are actually wired as a star.

star topology

The star topology, is the most commonly used physical topology in Ethernet LANs. • When installed, the star topology resembles spokes in a bicycle wheel. • The star topology is made up of a central connection point that is a device such as a hub, switch, or router, where all the cabling segments meet. • Each host in the network is connected to the central device with its own cable.

extended star topology

When a star network is expanded to include an additional networking device that is connected to the main networking device, it is called an extended-star topology.

bus topology

bus topology connects all the devices using a single cable

token passing

controls network access by passing an electronic token sequentially to each host. When a host receives the token, it can send data on the network. If the host has no data to send, it passes the token to the next host, and the process repeats itself.

broadcast topology

each host addresses its data to a particular NIC, to a multicast address, or to a broadcast address on the network medium

physical topology

refers to the physical layout of the devices and media