C
ONFIGURING
THE
S
WITCH
2-42
VLANs help to simplify network management by allowing you to move
devices to a new VLAN without having to change any physical
connections. VLANs can be easily organized to reflect departmental
groups (such as Marketing or R&D), usage groups (such as e-mail), or
multicast groups (used for multimedia applications such as
videoconferencing).
VLANs provide greater network efficiency by reducing broadcast traffic,
and allow you to make network changes without having to update IP
addresses or IP subnets. VLANs inherently provide a high level of network
security since traffic must pass through a configured Layer 3 link to reach a
different VLAN.
• Up to 255 VLANs based on the IEEE 802.1Q standard
• Distributed VLAN learning across multiple switches using explicit or
implicit tagging
• Port overlapping, allowing a port to participate in multiple VLANs
• End stations can belong to multiple VLANs
• Passing traffic between VLAN-aware and VLAN-unaware devices
• Priority tagging
Assigning Ports to VLANs
Before enabling VLANs for the switch, you must first assign each port to
the VLAN group(s) in which it will participate. By default all ports are
assigned to VLAN 1 as untagged ports. Add a port as a tagged port (that
is, a port attached to a VLAN-aware device) if you want it to carry traffic
for one or more VLANs and if the device at the other end of the link also
supports VLANs. Then assign the port at the other end of the link to the
same VLAN(s). However, if you want a port on this switch to participate