4.4 - Transmission Efficiency Flashcards
One objective of a ___________________________ is to move the highest possible volume of accurate information through the network – the higher the volume, the greater the resulting network’s efficiency and the lower the cost
data communication network
- Error rates and maximum transmission speed
- The speed of transmitting and receiving equipment
- The error-detection and control methodology
- The protocol used by the data link layer
Network efficiency is affected by the characteristics of the circuits such as:
The total number of information bits divided by the total bits in transmission
Transmission efficiency
Bits in the message sent by the user
Information bits
Information bits + overhead bits
Total bits
Start bit + stop bit(s) + parity bit
Overhead bits
Bits used to convey the user’s meaning
Information bits
Bits used for purposes such as error checking and marking the start and end of characters and packets
Overhead bits
Formula for transmission efficiency
transmission efficiency = information bits/total bits * 100
With asynchronous transmission, only _______ of the data rate is available for the user; _______ is used by the transmission protocol
70%…30%
We can improve efficiency by:
1. Reducing the number of __________ bits in each message, or
2. By increasing the number of __________ bits
overhead…increasing
______________ networks are usually more efficient than _____________ networks and that some protocols are efficient than others
Synchronous…asynchronous
The longer the ______________, the more efficient the protocol
message
Small frames are less efficient but are less likely to contain ___________ and cost less to retransmit if there is an error
errors
