priority field
The priority field, also known as traffic class, is a data field in the headers of various transport protocols in which the transmission priorities are specified.
InIPv6, the priority field is 8 bits long. It can be used to assign a total of 16 priorities to data packets. The priorities are divided into two groups of eight, for classic applications without real-time requirements and applications with real-time requirements.
The former group includes applications such as file transfer, e-mail and database access, i.e., applications to which no real-time requirements are attached. The priorities are subdivided numerically from 0 to 7 and can therefore also be used for flow control. Priority "0" represents uncharacterized traffic, priority "7" Internet control traffic, such as is used for SNMP. In this way, the data packets with the highest priority can be transmitted in the event of congestion.
The second group of eight with priorities 8 to 15 are assigned to real-time applications. Here, too, the higher priority represents the significance and importance of the service. Typical services are multimedia applications, audio and video.