The 802.1p method is a Quality of Service (QoS) process defined within the IEEE 802.1Q standard. The technique uses a three-bit field within an Ethernet frame header to assign priority levels to packets moving within a network segment. With the technique, this priority value is used to differentiate traffic. IEEE 802.1p specifies traffic prioritization at Layer 2 of the OSI model. 802.1p traffic priorities are included in the Virtual Local Area Network (VLAN) tags. Devices on a network that complies with the 802.1p signalling standard can classify data traffic into priority classes. When network congestion occurs, higher priority packets are transmitted before lower priority data.
Quality of Service Specifications
With the implementation of 802.1p, Quality of Service (QoS) specifications can be provided within networks that are based on 802 standards. Quality Of Service methods are established for a defined measure of performance. These QoS standards may also be referred to as Class of Service (CoS). 802.1p is also associated with the Generic Attributes Registration Protocol (GARP) and the GARP VLAN Registration Protocol (GVRP). GARP lets client stations request membership in a multicast domain, and GVRP lets them register into a VLAN.
802.1p in the 802.1Q Standard
The industry term 802.1p is commonly used, and often called a standard. However, 802.1p is not a formally published IEEE standard or amendment. The 802.1p does cover various elements, which are part of the IEEE 802.1Q standard. 802.1Q also offers specific recommendations regarding data traffic types and their corresponding priorities. The 1Q standard lists eight classes of service which are dictated by headers added to Ethernet frames. Contact Comms Express with questions about hardware that also contribute to QoS.