Network Topology & Protocols

Standards and Protocols:

Standards and protocols are required to govern the physical and logical connections between terminals, Computers and other equipment. They are vital for data communications and computer networking.

Typically, standard fall into two groups official standards (from national standards bodies) and defacto standards established by common usage.

An early official standard was the EIA RS232 for data transfer over wires (Electronic Industries Association Recommended Standard).

Network Topology:

The topology defines how the devices (Computers, printers… etc) are connected and how the data flows from one device to another. There are two conventions while representing the topologies. The physical topology defines how the devices are physically wired. The logical topology defines how the data flows from one device to another.

Broadly categorized into i) Bus ii) Ring iii) Star iv) Mesh

Data Transmission: Analog & Digital

Data Transmission: Analog and Digital

Analog Transmission:

Dominated the last 100 years and is here for a while yet networks designers made use of the existing telephone network which was aimed at voice transmission. This is actually very poor for computer networking for example, 2 computers connected by a direct cable can achieve a data rate of up to 100Mbps with very low error rate using phone lines, 56Kbps is the maximum transmission speed with a relatively high error rate. It is approximately 10 orders of magnitude worse the cost of bus ticket town versus a moon landing is same order of magnitude

Modems:

Data Communication and Computer Networks

Data Communication and Computer Networks

Data Communications has an ancient history, as people have always had an interest in communication with each other. Different methods have been used and associated with each method are various advantages and disadvantages. A major problem with communications is ensuring that the receiver gets the message sent by the transmitter.