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

Create and simulate a network - netml system, Create and simulate a network...

Create and simulate a network similar to the one shown here, using the NetML system. The network is a little more complex, as depicted at the right. There is an extra node

Who initiates the ‘trap'' message, Question 1 Who initiates the ‘Trap' mes...

Question 1 Who initiates the ‘Trap' message? When is this message generated? Question 2 Discuss the features of a typical Network Management System.List (Fault Management,

What is packet filter, What is packet filter? Packet filter is a standa...

What is packet filter? Packet filter is a standard router up to with some extra functionality. The extra functionality permits every incoming or outgoing packet to be inspected

What is groupware server, Groupware addresses the management of semi-struct...

Groupware addresses the management of semi-structured information like text, image, mail, bulletin boards and the flow of work. These Client/Server systems have people in direct co

Designing a network for a retail customer, You are designing a network for ...

You are designing a network for a retail customer; they plan to have 5 locations initially with the main store acting as the warehousing depot.  Within the next year they are plann

Networking concepts and applications, iLab 2: Office Network Expansion ...

iLab 2: Office Network Expansion Connect to the iLab here. Submit your assignment to the Dropbox located on the silver tab at the top of this page. (See "Due Da

Power supply system in satellite system, POWER SUPPLY SYSTEM IN  SATELLITE...

POWER SUPPLY SYSTEM IN  SATELLITE SYSTEM Satellite Earth Station relies on the public power supply system. Two generators (1+1) of 250 KVA each in parallel connection having fa

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