TOPOLOGY is one of the requirement for network.
Topology means arrangement of computers or structure of computer or design of the computer.
Types of Topology:
- Physical Topology:
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.
Physical Topology are visible we are having diffrent physical topoloy
A bus topology consists of a main run of cable with a terminator at each end
Advantages of a Bus Topology
- Easy to connect a computer or peripheral to a 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.
A star-wired ring topology may appear (externally) to be the same as a star topology. Internally, the MAU (multistation access unit) of a star-wired ring contains wiring that allows information to pass from one device to another in a circle or ring .The Token Ring protocol uses a star-wired ring topology.
A star topology is designed with each node (file server, workstations, and peripherals) connected directly to a central network hub or concentrator
Data on a star network passes through the hub or concentrator before continuing to its destination. The hub or concentrator 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.
The protocols used with star configurations are usually Ethernet or LocalTalk. Token Ring uses a similar topology, called the star-wired ring
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 or concentrator fails, nodes attached are disabled.
- More expensive than linear bus topologies because of the cost of the concentrators.
It similary like tree topology check bellow.
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.
2.
Logical Topology:
Logical Topology (also referred to as
Signal Topology) is a network computing term used to describe the arrangement of devices on a network and how they communicate with one another.
Logical topologies are bound to network protocols and describe how data is moved across the network
in logical topology we are having two models.
* Work group Model or Peer-To-Peer model.
** Domain Model or Client Server Model
*Work group Model or Peer-To-Peer model.
If you are installing any operating system default your computer is workgrop model
In Work group Model one computer does not depend on any other computers.
This work group machines also called as stand alone computers.
In work group model we are creating local user accounts.
In work group model we are suing SAM database , SAM stands for Security Accounts Manager.
** Domain Model or Client Server Model
Active Directory:
Active Directory is directory service which contains information of all user accounts and shared resources on a network.
Active Directory is a centralized Hierarchical database.
Purpose of Active Directory:
Active Directory provides user log on and authentication services using KERBEROS protocol.
To centralize and de-centralize the resource management
To centrally organize and manage user accounts, computers, groups and networking resources.
Enables authorized users to easily locate network resources.
