SMC Networks 6128L2, Management Manual

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VLAN C
ONFIGURATION
3-161
VLAN Configuration
Overview
In large networks, routers are used to isolate broadcast traffic for each
subnet into separate domains. This switch provides a similar service at
Layer 2 by using VLANs to organize any group of network nodes into
separate broadcast domains. VLANs confine broadcast traffic to the
originating group, and can eliminate broadcast storms in large networks.
This also provides a more secure and cleaner network environment.
An IEEE 802.1Q VLAN is a group of ports that can be located anywhere
in the network, but communicate as though they belong to the same
physical segment.
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.
This switch supports the following VLAN features:
• Up to 255 VLANs based on the IEEE 802.1Q standard
• Distributed VLAN learning across multiple switches using explicit or
implicit tagging and GVRP protocol
• 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