11.VLAN Configuration
In conventional networks with routers, broadcast traffic is split up into separate
domains. Switches do not inherently support broadcast domains. This can lead
to broadcast storms in large networks that handle traffic such as IPX or NetBeui.
By using IEEE 802.1Q-compliant VLANs, you can organize any group of network
nodes into separate broadcast domains, thus confining broadcast traffic to the
originating group. This also provides a more secure and cleaner network envi-
ronment.
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 applica-
tions 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
61
