1.
Strictly speaking, it is different. To put it simply, why the network has a delay is caused by the bandwidth delay and the amount of data to a certain extent; for example, it is very clear:
bandwidth, bandwidth, yes Refers to the maximum number of bytes transmitted per second. Bandwidth originally refers to the bandwidth of a certain signal, and the unit is Hz. Because in the past, analog signals were mainly transmitted, when digital signals are now transmitted, we still use this term to express the transmission rate.
I used to think that optical fiber transmits faster than ordinary twisted pair. You see, we download things much faster when we connect to the Internet in an Internet cafe than when we go online at home. It is true, but we may not understand it correctly. It is not that the light is "faster", but that the "amount" of the optical fiber is greater. To make a visual analogy, it is like a single lane and an 8-lane. Telephone lines for single lanes, 8 lanes are optical fibers. My previous understanding is reflected in the analogy of this lane: the car on the 8-lane runs faster than the car on the single-lane! This makes it easy to understand where we went wrong.
For example, we have 8 large trucks to go from A to B, and we can start on the road at the same time in 8 lanes, while the cars on a single lane can only drive forward one by one. At this time, the concept of transmission delay is involved. The transmission delay is simply the time that a piece of data is sent from when the first bit is sent to when the last bit is sent. So what our fiber optic line improves is only the transmission delay. But don't underestimate this delay, this benefit is considerable when processing large amounts of data.
(It should be not only the sending delay, but also the time waiting to be forwarded. The bandwidth is high ==> the sending delay of the sender is reduced + the router data packet queuing and waiting to be forwarded is reduced, anyway, more data can be sent at the same time)
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2. It
has nothing to do with bandwidth, even if it is 512 bandwidth, if it is only used for playing games, it will not feel stuck~~
The delay is generally due
to the access between the servers of different network providers, such as the port of Netcom, and the game played on the telecommunications server
2 There are downloads, online video and other large data transmissions on the same network outlet, or large data upload traffic
3 Viruses
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Third, the
delay has nothing to do with the bandwidth!
Latency has nothing to do with bandwidth!
Latency has nothing to do with bandwidth!
Latency is latency, and bandwidth is bandwidth. There is no dependency between the two. Every time I see a large group of people saying that they use 100M bandwidth to grab Xiaomi and tickets, I really smile. Guangxi Telecom's optical fiber home broadband ping Baidu has a delay of about 10ms, and any 100G broadband is not as good as the 1ms delayed 10M broadband of Guangdong Telecom's optical fiber broadband. Of course, only discussing ticket grabbing. Established on the premise that there is no need to load the page, just click the button, 100G bandwidth and normal delay broadband If there is no performance problem, the page opening speed must be greater than 10M bandwidth and very low delay broadband, after all, the process of opening a web page is not only It is latency. Large bandwidth allows you to load a large amount of data at the same time. Low latency allows you to communicate with the server in the first time. Therefore, people with low latency tend to grab Xiaomi tickets faster, and those with high bandwidth can only sigh. After all, grabbing Xiaomi will open the page first, and the fight is delay.
the above.
Q: When the bandwidth is not enough, the delay has a lot to do with the bandwidth.
A: When the bandwidth is not enough, the delay does seem to be higher, but in fact the part where the delay becomes higher is the time waiting for forwarding in the queue, and the delay from the local to the server remains the same. (The delay in sending data packets should be added)
Q: This is true in theory, but for the general application experience, it is indeed slow to respond (for improving user QoE, if the bandwidth is sufficient, the delay is related to the distance and the corresponding speed of the server, and the distance is also related to the "charge" "Station" means that the number of network devices such as routers is proportional. In this case, improving QoE can only be a routing strategy, such as multipath; bandwidth is not enough, except for the delay due to higher transmission and queuing forwarding, data packets can be split into multiple Path to reduce the delay of sending and queuing forwarding)
https://www.zhihu.com/question/21714530
Fourth,
the delay in the network is composed of the following different parts:
1. Sending delay: The sending delay is the time required for the host or router to send a data frame, that is, the time from the first bit of the frame to the end of the last bit of the frame.
2. Propagation delay: Propagation delay is the time it takes for electromagnetic waves to propagate a certain distance in the channel.
The propagation rate of electromagnetic waves in free space is the speed of light. The propagation rate of electromagnetic waves in network transmission media is slightly lower than in free space: the propagation rate in copper cables is about 2.3 10 to the 5th km/s, and the propagation rate in optical fibers is about 2.0 10 to 5 times. Square km/s. For example, the propagation delay caused by a 1000km-long optical fiber line is about 5ms.
Don't confuse the above two delays. As long as you understand where these two delays occur, you won't confuse them. The transmission delay occurs in the internal transmitter of the machine, and the propagation delay occurs on the transmission channel medium outside the machine. It can be illustrated by a metaphor that you see. Suppose a convoy of 10 vehicles departs from the entrance of a highway toll gate to a destination 50 kilometers apart. Assume the time it takes for each car to pass the toll station: the departure time takes 60 seconds (equivalent to the transmission delay in the network), and the travel time takes 30 minutes (equivalent to the propagation delay in the network), so the total cost is The time is 31 minutes.
The following two delays also need to be considered, but they are relatively easy to understand.
3. Processing delay: When the host or router receives the data, it takes a certain amount of time to process, such as analyzing the packet header, performing error checking or finding a suitable route, etc., which causes processing delay.
4. Queuing delay: When data is transmitted through the network, it has to pass through many routers. However, the data must be queued in the input queue for processing after entering the router. After the router determines the forwarding interface, it also queues up in the output queue for forwarding. This creates queuing delay. The length of the queuing delay often depends on the amount of communication on the network at that time. When the network traffic is very large, the queue will overflow and the packet will be lost, which is equivalent to the infinite queuing delay.
The total time delay experienced by data in the network is the sum of the above four kinds of delays:
Total delay = transmission delay + propagation delay + processing delay + queuing delay
https://www.zhihu.com/question/48899344
V.
1. The toll gate is too slow to pass, and you can often see a long line in front of the toll gate;
2. The road is too broken and too many lanes are too few, and the speed of the vehicle cannot rise;
3. The distance is indeed too far. From Shanghai to Urumqi, even if you don’t let go of the throttle at 200+ per hour, it will still take time;
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