29-05-2012, 05:31 PM
ATM NETWORKS
ATM NETWORKS.ppt (Size: 568.5 KB / Downloads: 50)
Introduction
Asynchronous transfer mode.
Drivers of the communication world.
Drivers are factors that helped in changing the communication processes
Technological Drivers
Drivers that impart direction to emerging technologies.
Four Key technological developments
Improvements in Processing speed
Improvements in transmission media
Growth of internet
Growth of mobile networks.
Improvements in Processing Speed
Maximum speed of data transfer depends on the slowest entity
Ex: if switches and routers are slow then this is non dependent of transmission speed as it gets limited by switches and routers.
In 1971 we use 4004 processor having 2250 transistors
After that 8080,8086,pentium I,II,III,4
Pentium 4 has 42 million transistors .VLSI
Through this increase we have three key influences in communication networks.
Switches and routers have become powerful and easier to transfer data at higher speeds.
Give rise to distributed environment like client server model.
As the ends systems have become powerful then, the reliable transfer and flow control is shifted to the end systems.
Improvements in transmission media
Optical fiber come into picture.
It supports higher bandwidths of say maximum 1 GB.
It is free from electro magnetic interference from external entities.
Signals from power sources electric storms has no effect on data transfer.
Because the bandwidth are non-overlapping in frequency domain.
Its bit error rate is very low.
Very little packet loss so retransmission and sequence numbering can be simplified.
It is limited to single bit errors. so error correcting lengths codes are smaller.
Attenuation is very low. Signal loss or degradation of signal is very low.
No repeaters used for long distances also.
Guided media so easy to detect errors.
Growth of internet
Provide services like email and file transfer.
Can create remote connection with the help of modem and a dial up connection.
Voice over internet telephony.
We can deploy the high speed networks and it provide good QoS.
Streaming audio and video are bandwidth extensive.