Vlan Functions - Lucent Technologies Cajun P220 Operation Manual

Optional per-VLAN spanning tree - This isolates loop control to smaller domains, so
spanning trees converge faster after a topology change. Otherwise, packets are
forwarded to the port's default VLAN.

VLAN Functions

A VLAN (Virtual LAN) is a logical group of hosts on a local area network (LAN) that
communicate as if they were on the same wire, even though they are physically on
different LAN segments throughout a site.
Virtual LANs 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 switch hardware supports Layer 1, Layer 2, and Layer 3 VLANs. The switch-based
VLANs have the following characteristics:
Frames classified as they enter the switch using Layer 1 (Port-based).
Explicitly-tagged VLAN packets are forwarded based on the information in the
packet.
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 (Figure 1-5).
Cajun P550/P220 Switch Operation Guide
Cajun P550 Switch Overview
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