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5
VLAN Configuration
This chapter includes the following topics:
◆
IEEE 802.1Q VLANs – Configures static and dynamic VLANs.
◆
Protocol VLANs
2
– Configures VLAN groups based on specified protocols.
◆
MAC-based VLANs
2
– Maps untagged ingress frames to a specified VLAN if the
source MAC address is found in the IP MAC address-to-VLAN mapping table.
IEEE 802.1Q VLANs
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 video conferencing).
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.
2. If a packet matches the rules defined by more than one of these functions, only one of them is
applied, with the precedence being MAC-based, protocol-based, and then native port-based.