The IEEE 802.1p standard is a method for assigning priority to packets traversing a network. It works with the MAC (media access control) header at the data link layer (Layer 2 in the OSI reference model). The MAC header is inspected by Switches in a network, which are also responsible for differentiating between network packets on the basis of their priorities.

The 802.1p sets a 3-bit value in the MAC header to indicate prioritization. This 3-bit value provides priority levels ranging from 0 to 7 (i.e., a total of 8 levels), with level 7 representing the highest priority. This permits packets to cluster and form different traffic classes. Thus, when network congestion occurs, those packets that have higher priorities will receive preferential treatment while low priority packets will be kept on hold.

802.1p is not backward compatible and can lead to instability on networks with non-802.1p Switches. This is because older Switches will misinterpret the header used by the 802.1p protocol. It is important that the Switches, Ethernet cards, and device drivers are all 802.1p compatible.

TEG-424WS allows the administrator to set priority levels of each port, and for the packets that are untagged the Switch will then set the priority in the tag depending on your configuration.