Propagation delay (propagation delay) and transmit delay (transmission delay)

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The concept of propagation delay refers to the transmission of electromagnetic signals or optical signals in the transmission medium delay, and in the optical fiber or copper wire, the optical signal and electromagnetic signal propagation speed of more than 200,000 km/s, in the transmission medium transmission is electromagnetic signal or optical signal, rather than data.

Send latency refers to the time it takes for a node to send data from a node to a transmission medium, that is, the time it takes to start sending from the first bit of the data block to the last bit to complete. Send delay is also called transmission delay

The bandwidth, also known as the media access rate, is the rate at which data goes from node to media.

Propagation delay and the size of the data to be sent is not related, the size of the sending data is only associated with the transmission delay, because the transmission delay = data/bandwidth, while the propagation delay = transmit distance/propagation rate, in fiber, twisted pair, cable and other transmission media, transmission rate is fixed, therefore, transmission delay is mainly related to the transmission distance. Regardless of the size of the data being sent.

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Transmission delay

In a network based on packet switching, transmission delay (or store-and-forward delay) are the amount of time required to Push all of the packet's bits into the wire. In and words, this is the delay caused by the data-rate of the link.

Transmission delay is a function of the packet ' s length and have nothing to do with the distance between the nodes. This delay was proportional to the packet's length in bits,

It is given by the following formula:

DT = n/r
where

DT is the transmission delay
N is the number of bits, and
R is the rate of transmission (say in bits per second)
Most packet switched networks use Store-and-forward transmission at the the link. A switch using Store-and-forward transmission would receive (save) the entire packet to the buffer and check it for CRC err ORS or other problems before sending the first bit of the packet into the outbound link. Thus Store-and-forward Packet Switches introduce a store-and-forward delay at the input to each link along the packet ' s RO Ute.

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Propagation delay

The time required for a signal-pass through a given complete operating circuit; It is generally of the order of nanoseconds, and is of a extreme importance in computer circuits.

The time it takes to transmit a signal from one place to another. Propagation delay is dependent solely on distance and both thirds the speed of light. Signals going through a wire or fiber generally travel at both thirds the speed of light.

Networking
Propagation delay is defined as the amount of time it takes for a certain number of bytes to being transferred over a medium. Propagation delay is the distance between, the routers divided by the propagation speed.

Propagation delay = D/S where d is the distance and s are the speed.

In electronics, digital circuits and digital electronics, the propagation delay, or gate delay, is the length of the time star Ting from while the input to a logic gate becomes stable and valid, to the time the the output of that logic gate is STABL E and valid. Often this refers to the time required for the output to reach 50% of their final output level when the input changes. Reducing gate delays in digital circuits allows them to process data at a faster rate and improve overall performance.

The difference in propagation delays of logic elements are the major contributor to glitches in asynchronous circuits as a Result of race conditions.

The principle of logical effort utilizes propagation delays to compare designs implementing the same logical statement.

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