February 29, 2012

Comparison of digital services with analog services

Analog Services   1- Analog Services uses FDM (Frequency Division Multiplexing) which is an analog technique. We use it because every modulated analog signal having different frequency because they are composite signals. So it is not possible that every time bandwidth can be used completely by the signals. By this the signals can overlap or […]

Reasoning for transmission medium is a part of the physical layer

Transmission medium is a part of physical layer because it is necessary to pass the data from source to target DTE. It deals with the mechanical and electrical specification of interface and transmission medium. Physical layer provide the encoded form of data to transmission medium, on other hand it receives data from transmission medium.

Significance of the twisting in twisted-pair cable

Twisted pair cables are of two types 1-         UTP (Unshielded Twisted Pair) 2-         STP (Shielded Twisted Pair) UTP: It is cost effective; the cost is the main advantage which it provides. Categories: There are 5 categories of UTP Category 1: Low speed data, fine for voice Category 2: Works for data transmission but up to […]

What is the purpose of cladding in an optical fiber

There are two layers of optical fiber, the inner layer and the outer layer. A data travel through inner layer which is consisting of central hollow material is known as core which is denser; it’s made of either glass or a plastic. This core is covered by a less dense material known as cladding the […]

How does sky propagation differ from line-of-sight propagation

Sky propagation is not limited to send signals to receivers, line-of-sight is dependent on direction, range and objects which may occur between sender and receiver. Sky propagation is not limited in sense of distance of source and destination and not restricted by being in range or in direction with antennas. In this case, signals are […]

February 25, 2012

hybrid topology with a star backbone connecting two bus backbones

Each bus backbone connects three ring networks

consequences if a connection fails

Following four networks and consequences if a connection fails.   a. Five devices arranged in a mesh topology b. Five devices arranged in a star topology (not counting the hub) c. Five devices arranged in a bus topology d. Five devices arranged in a ring topology   Details:   a) Mesh Topology   If five […]