Computer Networking Fundamental

network? The most crucial criteria are performance, credibility and 

security. The performance of the system depends on the number of users, 

type of transmission medium, along with the capacities of the 

connected h\/w and the efficiency of the s\/w.Reliability is 

measured by frequency of failure, that the time it can take a link to 

recuperate from the collapse along with the network's robustness in a

catastrophe. Security issues include protecting data from 

unauthorized access and viruses. 

Group the OSI layers by function? The seven layers of that the OSI 

model belonging to 3 subgroups. Physical, data link and system 

layers are the system support layers, they manage the physical 

elements of transferring data from one device to another. Session, 

the application and presentation layers are the user service layers, 

Computer Networking Fundamental

they let interoperability among unrelated applications systems. The 

transportation layer guarantees end-to-end reliable data 

transmission. What're trailers and header along with how to do they 

get added along with removed? Every layer in the sending system 

adds its info into the material it receives in the layer just above it 

and moves the entire bundle to the layer below it. 

This info is added in the shape of headers or trailers. Headers are 

added onto the message at the layers 6, 5, 4, 3, and 2.A trailer is 

added at layer2. From that the receiving machine, that the headers 

or trailers connected to the information unit in that the 

corresponding sending layers are removed, and activities suitable 

to that layer are taken. What're the attributes supplied by layering? 

It decomposes the problem of constructing a network into more 

manageable parts. It provides a more modular design. 

Why are the protocols needed? In networks, communication occurs 

between the entities in different systems. Two entities can't 

just send bitstreams to one another and expect to be understood. 

For communication, the entities must agree on a protocol. A 

the protocol is a set of rules this regulates data communication. What're 

the two interfaces provided by protocols? Service interface- 

defines the operations this local objects may perform on the 

protocol. Peer interface- defines the form and meaning of 

messages exchanged between protocol peers to implement that 

the communication service. 

Mention the different physical media? Define Signals? Signals will 

be actually electromagnetic waves traveling at that the speed of 

light. The speed of light is, however, medium dependent 

electromagnetic waves traveling through copper along with fiber 

can so at about two thirds the speed of light in a vacuum. What's waves wavelength

? The distance between a pair of adjacent 

maxima or minima of a wave, typically measured at meters, is 

called wave wavelength. 10. Define Modulation? Modulation -

varying that the frequency, amplitude, or phase of that the signal to 

an effect that the transmission of information. A simple example of 

modulation is into vary that the power of a single wavelength.