A family of IEEE
Local Area Network (LAN) standards. The services and protocols specified by the 802 standards map to
Layer 1 (L1) and
Layer 2 (L2) of the
Open Systems Interconnection (OSI) Reference Model:
IEEE specification which allows multiple LANs to be connected together through what the standard calls a “MAC bridge” which filters data sent between LAN segments, allowing networks to be partitioned for administrative purposes and reducing network congestion. The more common term for a MAC bridge is
switch. The 802.1D standard includes
Spanning Tree Protocol (STP) and
Rapid Spanning Tree Protocol (RSTP).
IEEE
802.1Q defines priority signaling for traffic that can be used by
Quality of Service (QoS) mechanisms to differentiate traffic. Packets are tagged as belonging to a queue, which determines the priority of the packet. Although this technique is often called “802.1p”, there is no standard by that name. Instead, the technique is incorporated into 802.1Q standard.
IEEE
Virtual Local Area Network (VLAN) and
Multiple Spanning Tree Protocol (MSTP) specifications. This standard refers to VLANs as “virtual bridged networks”. The
802.1D standard covers “VLAN-unaware” switches, while 802.1Q extends 802.1D for “VLAN-aware” switches.
Amendment to IEEE
802.1Q to classify incoming packets based on data link layer protocol identification.