802.1p is an Ethernet tagging mechanism that can process Ethernet switches to give priority to voice packets.

The 802.1p feature is important to the endpoint side of the network because personal computer-based endpoints must rank audio traffic over routine data traffic.

For IEEE standard 802.1Q, you must specify both a virtual LAN (VLAN) and a frame priority at layer 2 for LAN switches or Ethernet switches, for routing based on MAC addresses.

802.1p/Q provides 8 priority levels and many Virtual LAN identifiers. Interpretation of the priority is controlled by the Ethernet switch and is usually based on highest priority first. The VLAN identifier permits segregation of traffic within Ethernet switches to reduce traffic on each link. 802.1p operates on the MAC layer. The switch always sends the QoS parameter values to the IP endpoints. Attempts to change the settings by DHCP or manually are overwritten. The IP endpoints do not process the VLAN on or off options. Turning VLAN on requires that the capabilities be administered on the LAN switch nearest to the IP endpoint. VLAN tagging can be turned on manually, by DHCP, or by TFTP.

If you have varied 802.1p from LAN segment to LAN segment, then you must administer 802.1p/Q options individually for each network interface. You require a separate network region for each network interface.