chapter 2 =Topology

TOPOLOGY

- It referes in 2 types as physical or logical arrangment of network

* Types of topologies in physical
1. Single node
2. Bus
3. Star
4. Ring
5. Mesh
6. Tree
7. Hybrid

1. Single node Topology :-

 * single device , at times device called dumb terminal is connected to the server
 * Devices operates on files from server & returns them back after completing the task

ADVANTAGE :-
1. Easy to install configure & manage
2. Least expensive
3. Single cable is requried

DISADVANTAGE :-
1. Network consists of single device
2. Dumb terminal is depend on server

2. Bus topology :-

* All devices are connected to common cable  called trunk

* Maximum segment length of cable is (200 m)

* Maximum 30 devices per segment

* Terminal are used to transfer data within the trunk terminal 

* when 2 singnal colides collision occures

* 50 OHM terminator is used

* Server is at one end and devices are at different positions.

* It operates at half duplex

ADVANTAGE :-

1. Installing device is easy

2. Requries less cables compare to star topology

3. Less expensive & works better for smaller network.

DISADVANTAGE :-

1. If back bonebreaks entire networks gets down.

2. Difficult to isolate problems

3. Limited number of devices.

3. Star topology:-

* Each devices is connected to centrilized network

* Data passes through centrilized network before destination

* Star topology with switch doesn't broadcast data it will transfer data to specific destination

* Multiple device can transmit or recive data at a time.

* It operates at full duplex

ADVANTAGE :-

1. Easy to configure , manage , install , expand

2. Centralized managment

3. Addition or removal of device dose not effect the whole network

DISADVANTAGE:-

1. Requries more cable

2. Failure of hub effects entire network

3. More expensive

4. Ring topology :-

* Devices are connected in closed loop

* All devices have equal access to media

* Device waits for its turn to transmit

* Most common type of token ring

ADVANTAGE :-

1. Data travels at great speed.

2. No collisions

3. Handels large volume of traffic

DISADVANTAGE :-

1. More cabling is requried as compared to BUS 

2. One faulty device effect the entire network

3. Addition of devices effect network

5. Dual Ring topology :-

* Consist of two independent primiry and secondary rings

* Secondary ring is redundant , used only when primary stops functioning

5. Mesh topology :-

* Used in WANs to inter connect LANs

* Every device is connected to every other device

* Use routers to determine the best path of communication

ADVANTAGE :-
1. Improves fault tolerance
2. Failure of one link does not effect entire network
3. centrilized managment is not required

DISADVANTAGE :-
1. Difficult to install & manage
2. Each link from one device to other requires individual NIC
3. Very much expensive

THERE ARE TWO TYPE OF MESH

1. Full mesh = All devices are connected to each other

2. Partial mesh =Some devices are connected to only those with whom they exchange most of the data

6. Tree topology :-

* Connects group of star network

* Device are wired to root hub

* Root hub is connect to second level devices

* Lowest level devices are smaller computers

ADVANTAGES :-
1. Easy to add new devices
2. Point to point wiring for each devices
3. Fault detection is easy

DISADVANTAGES :-
1. Difficult to configure
2. If backbone breaks entire network gose down
3. More expensive

7. Hybrid topology :-

* Combines two or more different physical topology

* Commonly star-bus or star-ring

* Star-ring uses Multistation access unit (MAU)

ADVANTAGE :-

1. Used for creating large networks

2. Handels large volume of traffic

3. Fault detection is easy

DISADVANTAGE :-

1. Installation and configuration is difficult

2. More expensive then other topology

3. More cabling is required