TOPOLOGY

TOPOLOGY

Bus Topology

Ring Topology

Star Topology

Tree Topology

Mesh Topology

What is a Topology?

The physical topology of a network refers to the configuration of cables, computers, and other peripherals. Physical topology should not be confused with logical topology which is the method used to pass information between workstations.

Main Types of Physical Topologies

The following sections discuss the physical topologies used in networks and other related topics.

• Bus Topology
• Ring Topology
• Star Topology
• Tree Topology
• Mesh Topology

1. Bus Topology

A linear bus topology consists of a main cable in middle where nodes(file server, workstations, and peripherals) are connected. Terminator is connected at each end. T-Connector is used in the cable to add new nodes in the network.
 Advantages

• Easy to connect a computer or peripheral to a linear bus.
• Requires less cable length than a star topology.

Disadvantages of a Linear Bus Topology

• Entire network shuts down if there is a break in the main cable.
• Terminators are required at both ends of the backbone cable.
• Difficult to identify the problem if the entire network shuts down.
• Not meant to be used as a stand-alone solution in a large building.

2. Ring Topology

A ring topology is a network topology or circuit arrangement in which each network device is attached along the same signal path to two other devices, forming a path in the shape of a ring. Each device in the network that is also referred to as node handles every message that flows through the ring. Each node in the ring has a unique address. Since in a ring topology there is only one pathway between any two nodes, ring networks are generally disrupted by the failure of a single link.
Ring topologies are used on token ring networks. Each device processes and retransmits the signal, so it is capable of supporting many devices in a somewhat slow but very orderly fashion. A token, or small data packet, is continuously passed around the network. When a device needs to transmit, it reserves the token for the next trip around, then attaches its data packet to it. The receiving device sends back the packet with an acknowledgment of receipt, then the sending device puts the token back out on the network.
Advantages

• An orderly network where every device has access to the token and the opportunity to transmit
• Under heavy network load performs better than a start topology.
• To manage the connectivity between the computers it doesn't need network server.

Disadvantages

• One malfunctioning workstation can throw away the entire network.
• Moves, adds and changes of devices can affect the entire network.

3. Star Topology

A star topology is designed with each node (file server, workstations, and peripherals) connected directly to a central network hub or switch.
Data on a star network passes through the hub or switch before continuing to its destination. The hub manages and controls all functions of the network. It also acts as a repeater for the data flow. This configuration is common with twisted pair cable; however, it can also be used with coaxial cable or fiber optic cable.
Advantages of a Star Topology

• Easy to install and wire.
• No disruptions to the network when connecting or removing devices.
• Easy to detect faults and to remove parts.

Disadvantages of a Star Topology

• Requires more cable length than a linear topology.
• If the hub, switch, or concentrator fails, nodes attached are disabled.
• More expensive than linear bus topologies because of the cost of the hubs, etc.

4. Tree Topology or Expanded Star

A tree topology combines characteristics of linear bus and star topologies. It consists of groups of star-configured workstations connected to a linear bus backbone cable .  Tree topologies allow for the expansion of an existing network, and enable schools to configure a network to meet their needs.
Advantages of a Tree Topology

• Point-to-point wiring for individual segments.
• Supported by several hardware and software venders.

Disadvantages of a Tree Topology

• Overall length of each segment is limited by the type of cabling used.
• If the backbone line breaks, the entire segment goes down.
• More difficult to configure and wire than other topologies.

5. Mesh Topology

Mesh Network is a network where all the nodes are connected to each other and is a complete network. In a Mesh Network every node is connected to other nodes on the network through hops. Some are connected through single hops and some may be connected with more than one hope.
While the data is traveling on the Mesh Network it is automatically configured to reach the destination by taking the shortest route which means the least number of hops. Data travels by hopping from one node to another and then reaches the destination node in a Mesh Topology Network. An example of a Mesh Network is the Internet.

6. Hybrid Topology

Hybrid topology is the combination of two or more topologies together. It has the advantage of more than one topologies as well as disadvantages, too.