Introduction 17VLAN Supported FeaturesVLAN SupportVLANs are collections of switching ports that comprise a single broadcast domain. Packets are classifiedas belonging to a VLAN based on either the VLAN tag or based on a combination of the ingress port andpacket contents. Packets sharing common attributes can be grouped in the same VLAN.For more information, see "Configuring Multiple Spanning Tree" on page 317.Port Based Virtual LANs (VLANs)Port-based VLANs classify incoming packets to VLANs based on their ingress port.For more information, see "Defining VLAN Ports Settings" on page 331.IEEE802.1V Protocol Based Virtual LANs (VLANs)VLAN classification rules are defined on data-link layer (Layer 2) protocol identification. Protocol-basedVLANs isolate Layer 2 traffic for differing Layer 3 protocols.For more information, see "Defining VLAN Protocol Groups" on page 337.Full 802.1Q VLAN Tagging ComplianceIEEE 802.1Q defines an architecture for virtual bridged LANs, the services provided in VLANs and theprotocols and algorithms involved in the provision of these services. An important requirement includedin this standard is the ability to mark frames with a desired Class of Service (CoS) tag value (0-7).QinQQinQ tagging allows network managers to add an additional tag to previously tagged packets. CustomerVLANs are configured using QinQ. Adding additional tags to the packets helps create more VLAN space.The added tag provides an VLAN ID to each customer, this ensures private and segregated networktraffic. The VLAN ID tag is assigned to a customer port in the service providers network. The designatedport then provides additional services to the packets with the double-tags. This allows administrators toexpand service to VLAN users.GVRP SupportGARP VLAN Registration Protocol (GVRP) provides IEEE 802.1Q-compliant VLAN pruning anddynamic VLAN creation on 802.1Q trunk ports. When GVRP is enabled, the device registers andpropagates VLAN membership on all ports that are part of the active underlying "Spanning Tree ProtocolFeatures" on page 18 topology.For more information, see "Configuring GVRP" on page 340.
