- Link: connects adjacent nodes Wires, Cables, Any thing that physically connects two nodes
- Path: end-to-end route within a network
- Circuit: the conduit over which data travels
- Packetzing: dividing messages into fixed-length packets prior to transmission over a network’s communication media
- Routing: determining a message’s path from sending to receiving nodes
- The transmission medium may itself be a network, so route needs to be specified
Network“A NETWORK is a set of devices (Nodes) connected by Communication Links”- Node: Can be a Computer, Printer or any other device capable of sending or receiving
- The links connecting Nodes are called COMMUNICATION CHANNELS Networks- Why we need them?
Networks- Why we need them?It is often impractical for devices to be directly connected for two major reasons:
- The devices are very far apart. They are expensive to connect just two devices with one in Lahore and other in Islamabad
- Large set of devices would need impractical number of connections e .g. Telephone Lines in the world and all the computers owned by a single organization
Solution to the Problem=Networks- Solution is to connect all devices to a central system known as a NETWORK in which all terminals or computers share the links.
- Two Main Classifications of the Networks
DISTRIBUTED PROCESSING- Instead of a single large machine being responsible for all aspects of a process ,each separate computer handles a subset of the task
- Example – Project Given as a part of the Course
- Example – Office Work
Advantages of Distributed ProcessingA system designer can limit the kind of interaction that a given user can have with
the entire system.
No one system need to provide storage capacity for the entire database
- For example WWW gives user access to pages stored anywhere on Internet
Multiple computers working on a problem can solve a problem faster than a
computer working alone
- Security through Redundancy
Multiple computers running the same program provide security through redundancy
If one computer's hardware breaks down others cover up
Both multiple computers and multiple users can interact for a task