How do customers need us to evaluate the performance of a network, and we can evaluate it from these four aspects.
1. Bandwidth :
Bandwidth is defined in Baidu Encyclopedia: the “highest data rate” that can pass from one point in the network to another point per unit of time.
The bandwidth of a computer network is the highest data rate through which the network can pass, namely how many bits per second (the common unit is bps (bit per second)).
Simply put: bandwidth can be compared to the highway, indicating the number of vehicles that can pass per unit of time;
2. Bandwidth representation:
Bandwidth is usually expressed as bps, indicating how much bit per second;
“Bits per second” is often omitted when describing bandwidth. For example, the bandwidth is 100M, which is actually 100Mbps, where Mbps refers to megabits/s.
But the unit of the speed we usually download software is Byte/s (byte/second). This involves the conversion of Byte and bit. Each 0 or 1 in the binary number system is a bit, and a bit is the smallest unit of data storage, of which 8 bits are called a byte.
Therefore, when we handle broadband, 100M bandwidth represents 100Mbps, the theoretical network download speed is only 12.5M Bps, actually may be less than 10MBps, this is because of the user computer performance, network equipment quality, resource usage, network peak, network service capacity, line decay, signal attenuation, the actual network speed is unable to reach the theoretical speed.
2.Time delay:
Simply put, delay refers to the time needed for a message to go from one end of the network to the other;
From the ping results, you can see that the time delay is 12ms, which refers to the ICMP message from my computer to Baidu’s server required time-trip time delay is 12ms;
(Ping refers to the back and forth time when a packet is sent from the user’s device to the speed measurement point, and then immediately returned to the user’s device. That is, commonly known as the network delay, calculated in millisecond ms.）
Network delay includes four parts: processing delay, queuing delay, transmission delay and propagation delay. In practice, we mainly consider the transmission delay and transmission delay.
3.Shake
: network jitter refers to the time difference between the maximum delay and the minimum delay. For example, the maximum delay when you visit a website is 10ms, and the minimum delay is 5ms, then the network jitter is 5ms; jitter = maximum delay-minimum delay，shake = maximum delay-minimum delay
shake can be used to evaluate the stability of the network, the smaller the jitter, the more stable the network;
Especially when we play games, we need the network to have high stability, otherwise it will affect the game experience.
About the cause of network jitter: if the network congestion occurs, the queuing delay will affect the end-to-end delay, which may cause the delay suddenly large and small from router A to router B, resulting in the network jitter;
4.Packet loss
: Simply put, packet loss means that the data of one or more data packets cannot reach the destination through the network. If the receiver finds that the data is lost, it will send a request to the sender according to the queue serial number to conduct packet loss and retransmission.
There are many reasons for losing packets, the most common may be the network congestion, data traffic is too large, the network equipment can not handle the naturally some data packets will be lost.
The packet loss rate is the ratio of the number of packets lost in the test to the packets sent. For example, if you send 100 packets and lose one packet, the packet loss rate is 1%.
Post time: Oct-28-2022