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1. Standardization work and related organizations
3. Queue delay, processing delay
1. Standardization work and related organizations
1. Standardized work
2. Performance indicators
1. Rate
rate or data rate or data transfer rate or bit rate
Bit 1/0 here (meaning: transmitted as 0 or 1)
2. Broadband
It can be seen from the figure that the larger the bandwidth, the more data transmitted per unit time.
3. Throughput
Indicates the amount of data passing through a network (or channel, interface) in unit time . The unit is b/s, kb/s, Mb/s, etc.
Throughput is limited by the bandwidth of the network or the rated rate of the network.
Here's an example to help you understand:
The blogger is a big eater and I can eat up to 100 bowls of noodles at a time. This is the bandwidth
My good friend gave me 66 bowls of noodles, and I finished the 66 bowls of noodles. This is equivalent to throughput
The blogger can obviously eat 100 bowls of noodles, but my friend only gave me 66 bowls.
Broadband: 100 Throughput: 66
4. Delay
Refers to the time required for data (message/packet/bit stream) to travel from one end of a network (or link) to the other. Also called delay or delay. unit is s
Example: The following figure demonstrates A to B transmission
1. Sending delay
The time required to send the last bit of the packet (for example, the last bit of 0 10101010 1 is 0 ) from the first bit of the sending packet (for example, the first bit of 0 10101010 1 is 1 ) is completed.
For example: the time to send the data 0101010101 from itself (computer A) to the channel (blue line in the figure below).
Therefore, the transmission delay is affected by two factors: data length ( 0101010101 ) and channel bandwidth
Hence:
Because the data length is 10 ( 0101010101 ) which is 10b
Assuming our channel bandwidth here is 10b/s then sending delay=10/10=1s
2. Propagation delay
Depends on electromagnetic wave propagation speed and link length
3. Queue delay, processing delay
Queuing Delay: Waiting for Incoming/Outgoing Links to Be Available
Processing delay: error detection, find exit
As shown in the figure below, when 0101010101 arrives at the router, you need to wait for a while, that is, the (queuing) queuing delay (this is like when you go to the subway, you need to queue for security check), and then the processing delay (for example, you go through security check ) When you arrive, the security inspector will check you for errors and check whether you are carrying contraband), after the processing is completed, you need to queue up and go out again (dequeue) queuing delay (for example, after you have been checked for security, you have to queue up you take your luggage)
5. Delay bandwidth product
6. Round-trip delay RTT
The total delay experienced from the sender sending data to the sender receiving the acknowledgment from the receiver (the receiver sends the acknowledgment immediately after receiving the data).
7. Utilization
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