Several definitions of network performance indicators

Latency 

  Network latency
  Network latency means that a data packet is sent from the user's computer to the website server, and then immediately from the website serviceThe return time of the user's computer. We usually use the network management tool Ping (packet Internet grope) to measure network latency.
  Due to the complexity of the interconnected network, the dynamic change of network traffic, and the dynamic selection of network routes, the network latencyChanges are constantly called jitter ). The smaller the jitter between network latency and network latency, the better the network quality.
  On the Internet, the typical network latency is dozens to hundreds of milliseconds. The main factor affecting network latency is the RoutingThe number of hops (because each route forwarding takes time, the larger the number of hops, the larger the network latency) and the network traffic (the larger the network traffic, the longer the queue time between the vswitch and the vro, the longer the network latency ).

Latency refers to the interval between the time when the switch receives data packets and replicates data packets to the destination port. There are many factors that affect the latency, such as forwarding technology. Vswitches using the forward-through technology have fixed latency. Because a pass-through switch determines the forwarding direction based on the destination address regardless of the overall data packet size. Therefore, the latency is fixed, depending on the rate at which the switch interprets the destination address in the first six bytes of the data packet. Because a vswitch using the storage and forwarding technology must receive complete data packets before it starts to forward data packets, its delay is related to the packet size. If the data package is large, the latency is large; if the data packet is small, the latency is small. The Gigabit Switch Using pass-through forwarding technology has a fixed delay because the pass-through switch determines the forwarding direction only based on the destination address regardless of the overall data packet size. Therefore, its latency is fixed. Because a vswitch using the storage and forwarding technology must receive the complete data packet before it starts to forward the data packet, its data packet is large, and the delay is large; if the data packet is small, the delay is small.

JitterJitter is a common concept in QoS, which means the variation degree of group latency.

If the network is congested, the queuing delay will affect the end-to-end delay, and the packet delay transmitted through the same connection is different. The jitter is used to describe the degree of delay change.
Therefore, jitter is an important parameter for real-time transmission, such as VoIP and video.
If it is restrained, QoS is usually used to ensure the relevant stream ~~

Of course, you can also use the buffer zone to solve some problems!

Packet LossPacket Loss Rate is a ratio. Data Transmission in the network is in the form of sending and receiving data packets. Ideally, it is the number of packets that can be received after the packet is sent, however, due to signal attenuation, network quality, and other factors, there will be no ideal results, that is, the number of packets that can be received will not be sent.

  Network Packet Loss Rate refers to the ratio of the number of lost data packets in the test to the number of sent data packets, usually in the throughput rangeInternal testing.
  Packet Loss Rate is mainly related to network traffic, which is accurate to each route segment from the user's computer to the website server.. Due to limited processing capabilities of vswitches and vrouters, some data packets are discarded when the network traffic is too high to be processed, resulting in packet loss. Because TCP/IP networks can automatically resend packets, packet loss occurs and the packets are resend continuously, resulting in more packet loss. Therefore, packet loss rate increases frequently when network congestion occurs, which is very similar to traffic congestion on the road.

 

Download speed

Download speed refers to the speed at which the webpage is displayed from the website. This is another important indicator of the customer's online experience.

The download speed is mainly related to the network bandwidth. In the same case, the longer the network latency, the higher the packet loss rate, and the lower the download speed. Currently, the ADSL Broadband Network is widely used, and the network download speed generally exceeds 50 kbps (kilobytes per second ). When the network download speed is lower than 5 kbps, users will obviously feel that the network is particularly slow and unbearable.

 

QoS

QoS (Quality of Service) is a security mechanism that normally does not require QoS, but it is necessary for key applications and multimedia applications. When the network is overloaded or congested, qoS ensures that important services are not delayed or discarded, and the network runs reliably.

1. higher reliability and faster response speed;

2. helps reduce the burden on network demands and make full use of existing bandwidth;

3. control to avoid adverse use;

4. Expand the scope of commercial applications, save costs, and improve efficiency.

The Chinese meaning of QoS is: the quality of online services. Specifically, it refers to various communication or program type priority technologies applied on the entire network connection. The existence of QoS technology is to achieve better network service quality. QoS is a set of service requirements. The network must meet these requirements to ensure proper service-level data transmission.

The implementation of QoS allows real-time applications such as network TVs and Network music to use network bandwidth most effectively. Because it can ensure that a guaranteed level has sufficient network resources, it provides a service level similar to that of a dedicated network. It also provides a means to notify the application of resource availability, so that the application can modify requests when resources are limited or used up. The purpose of introducing QoS Technology in Windows XP is to establish a guaranteed transmission system for network communication.

QoS is classified. When the network is smooth, no one will be affected. When the network is blocked, the high level gives priority to communication. As for the classification of high and low levels, it is estimated that the division of the economic level is used.