Asynchronous or statistical time division multiplexing, Computer Networking

Assignment Help:

Asynchronous or Statistical Time Division Multiplexing

As we  have seen  synchronous  TDM does not  guarantee that the full capacity of a link in sued. In fact it is more likely  that only  a portion of the  time slots are in use at a given  instant. Because  the time  slots  are reassigned and  fixed whenever a connected device is not  transmitting, the  corresponding  slot is empty and that much   capacity of the path  is wasted. For  example imagine that we have multiplexed the output of 20 identical computer onto a single line. Suing synchronous TDM the speed  of that line must be at  least 20 times the speed of each input line. But  what  if only 10 computers  are in use at a time ? half of the capacity  of the line  is wasted.

Statistical  time  division  multiplexing is designed to avoid this type of waste. As with  the term  synchronous. The term  asynchronous means some  things   different  in multiplexing  that it  means  in other  areas of data communications. Here it  flexible  or not  fixed.

Like synchronous TDM asynchronous TDM allows  a number of lower  speed  input  lines  to be  multiplexed  to a single  higher speed  line. Unlike  synchronous  TDM however in asynchronous TDM the total  speed of the input  can be greater than  the capacity  of the path. In a synchronous systems if we have in  input  lines. The frame contains a fixed number of a least m time  slots. In  an asynchronous systems. If  we have  n input line the  frame contains no more  than  m slots with m less than n. In  this way asynchronous TDM supports  the same  number of input lines as synchronous TDM with a lower capacity  link or given the same  link. Asynchronous TDM can support more  devices  than  synchronous TDM.

1558_Asynchronous or Statistical Time Division Multiplexing.gif

figure Asynchronous TDM

The number  of time  slots in an asynchronous TDM fame is based on a statistical analysis of the number  of input lines that are likely to be transmitting at any given  time. Rather than being reassigned each slot  is available to any  of the attached input lines  that has data  to seen. The  multiplexer scans the input lines accept portions of data until a frame is felled and then sends the frame across the link. If  there are not enough data to  fill all the  slot s in a frame the frame a transmitted only partially filled thus full link capacity  may not be used 100 percent   of the time. But  the ability to allocate time slots  dynamically coupled with  the lower  ration of the slots  to input  greatly reduces the likelihood and degree  of waste.

 

 


Related Discussions:- Asynchronous or statistical time division multiplexing

Low-earth-orbiting leo satellites , LOW-Earth Orbiting have more advantageo...

LOW-Earth Orbiting have more advantageous in Mobile based communication devices like PDAs, Cell phones and automobile communications. The LOW-Earth Orbiting is a satellite of orbit

Calculate the voltage on the capacitor, Quetion: A 22 nF capacitor is i...

Quetion: A 22 nF capacitor is initially charged to 10V. It is then discharged by connecting a 100kW resistor across it. Approximately how long does it take for the voltage on t

SAN, Case study on SAN Providers and Products available in the market.

Case study on SAN Providers and Products available in the market.

Delay, It is a basic quantitative property of networks. Delay is a calculat...

It is a basic quantitative property of networks. Delay is a calculate how long it takes for a bit of data to cross across the network from one end to the other. It is calculated in

Illustrate 802.11 csma, 802.11 CSMA/CA a) Wait a DIFS time to avoid col...

802.11 CSMA/CA a) Wait a DIFS time to avoid collision b) Send RTS and wait for CTS reply to obtain the use of the Medium (air) c)  Use of SIFS time for control informatio

Standard ip access-list use as test criteria, What does a Standard IP Acces...

What does a Standard IP Access-list use as test criteria Ans) Standard IP access list use only source address.

What is protocol data unit, What is Protocol Data Unit? The data unit i...

What is Protocol Data Unit? The data unit in the LLC level is known as the protocol data unit (PDU). The PDU having of four fields a destination service access point (DSAP), a

What is nic - networking, NICs Network interface cards, commonly referr...

NICs Network interface cards, commonly referred to as NICs are used to connect a PC to a network. The NIC gives a physical connection among the networking medium and the comput

Networks classification - point to point network , Normal 0 fal...

Normal 0 false false false EN-IN X-NONE X-NONE Networks classification

How firewall configuration makes all the difference, How Firewall configura...

How Firewall configuration makes all the difference The greatest blunder that any company make is to just install a firewall and think that they have ensured perfect securit

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd