VLANs are a method for segmenting a network into related groups, improving the efficiency of traffic flow and limiting the propagation of multicast and broadcast messages. Traffic between VLANs is blocked unless the VLANs are connected by a router, increasing security.
A VLAN is a group of ports designated by the switch as belonging to the same broadcast domain. That is, all ports carrying traffic for a particular subnet address would belong to the same VLAN. Using a VLAN, you can group users by logical function instead of physical location. This helps to control bandwidth usage by allowing you to group high-bandwidth users on low-traffic segments and to organize users from different LAN segments according to their need for common resources. You can use the switch's console interface to configure up to 30 port-based, IEEE 802.1Q-compliant VLANs. This enables you to use the same port for two or more VLANs and still allows interoperation with older switches that require a separate port for each VLAN.
The GARP VLAN Registration Protocol (GVRP) is an 802.1Q-compliant method for facilitating automatic VLAN membership configuration. GVRP-enabled switches can exchange VLAN configuration information with other GVRP-enabled switches. Unnecessary broadcast traffic and unicast traffic also can be reduced.
Policy rules or other network management methods can determine who is admitted to a VLAN. When a node requests admission to a specific VLAN, GVRP handles the registration of the node with GVRP-enabled switches and maintains that information.
The GVRP protocol is described in the IEEE 802.1p standard.
For a more detailed description of how to use and configure VLANs, refer to the Management and Configuration Guide for your switch.
Note: If a switch is a Commander, the Stack options will appear at the top of the page.
Note: When multiple VLANs exist on a switch, only one VLAN can be untagged for each port. (In the default configuration, this is VLAN 1, the DEFAULT_VLAN.) When you add a second VLAN to a switch, the default setting on that VLAN is No for all ports. Using the Web browser interface, if you then reconfigure a port to Untagged for a new VLAN while there is an Untagged setting on another VLAN for the same port, the switch automatically reconfigures the other VLAN setting to No. For example, if you configure Port A1 as Untagged for the 2nd VLAN, then the switch automatically reconfigures DEFAULT_VLAN for port A1 as No.
Because certain features and management functions, such as single IP-address stacking, run on only one VLAN in the switch, and because DHCP and Bootp can run per-VLAN, there is a need for a "dedicated management VLAN" to ensure that multiple instances of DHCP or Bootp on different VLANs do not result in conflicting configuration values for the switch. The primary VLAN is the VLAN the switch uses to run and manage these features and data. In the factory-default configuration, the switch designates the default VLAN (DEFAULT_VLAN) as the primary VLAN. However, to provide more control in your network, you can designate another VLAN as primary. To view the primary VLAN setting, use the VLAN Information screen in the menu interface or the SHOW VLANS command in the CLI. To change the primary VLAN setting, use the VLAN Information screen in the menu interface or the PRIMARY VLAN command in the CLI.
From the Main menu of the switch console:
To modify ports in a VLAN:
The modes are:
The VLAN table includes a GVRP Enabled check box. If a check appears in this box, GVRP is enabled and the GVRP Mode button is active. To enable GVRP and view the current GVRP mode assignments for individual ports:
VLAN operation with:
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