VLANs

VLANs provide network managers with two significant capabilities:

• The ability to segment traffic in a flat switched network. This helps prevent traffic from being forwarded to stations where it is not needed.
• The ability to ignore physical switch locations when creating workgroups. VLANs are logical constructions and can traverse physical switch boundaries.

The hardware on all multiservice switches support port-based VLANs with the following characteristics:

• Frames classified as Layer 1 (port-based) when they enter the switch
• Explicitly tagged VLAN packets -- these are forwarded based on the information in the packet.
• Up to 1,000 VLANs -- VLANs define a set of ports in a flooding domain. Packets that need to be flooded are sent only to ports participating in that VLAN.

For more information on VLANs, see Chapter 6, “Using VLANs, Hunt Groups, and VTP Snooping.”