The traffic shown on the console is derived from our log recorded at the application layer, which is 7%-15% lower than the actual network traffic. Therefore, according to the industry standard, an additional 7% traffic overhead is included.
It is mainly because:
1. Consumption by the TCP/IP packet header:
As is known to all, our HTTP requests are based on TCP/IP. On the existing Internet, each packet contains up to 1,500 bytes , including a 40-byte header inserted by TCP/IP. However, the packet header is added by the core protocol stack and cannot be counted by the application layer. Therefore, our log does not record these 40 bytes. This portion of traffic may account for more than 2.74% (40/1460) of the logged traffic, normally around 3%.
2. TCP retransmission:
Depending on the physical Internet load, about 3-10% of the packets we send are discarded by the Internet. The server will retransmit such discarded packets over the core protocol stack but the application layer is unable to count these packets. As a result, such traffic may make up a percentage of our logged traffic. The retransmission rate may vary depending on the Internet connection quality. When Internet traffic is light early in the morning, the retransmission rate is low; during peak hours at night , the rate may usually rise to 3%-7%.