Introduction 15VLAN Supported FeaturesVLAN SupportVLANs are collections of switching ports that comprise a single broadcast domain. Packets are classified asbelonging 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 290.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 304.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 310.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 included inthis 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 network traffic.The VLAN ID tag is assigned to a customer port in the service providers network. The designated port thenprovides additional services to the packets with the double-tags. This allows administrators to expandservice to VLAN users.GVRP SupportGARP VLAN Registration Protocol (GVRP) provides IEEE 802.1Q-compliant VLAN pruning and dynamicVLAN creation on 802.1Q trunk ports. When GVRP is enabled, the device registers and propagates VLANmembership on all ports that are part of the active underlying "Spanning Tree Protocol Features" on page 16topology.For more information, see "Configuring GVRP" on page 313.
