Understanding VLANs

Aruba-OS wired switches are 802.1Q VLAN-enabled. In the factory default state, the switch is enabled for up to 256 VLANs. You can reconfigure the switch to support more VLANs. The maximum VLANs allowed varies according to the switch series.

A group of networked ports assigned to a VLAN form a broadcast domain configured on the switch. On a given switch, packets are bridged between source and destination ports that belong to the same VLAN.

VLANs enable grouping users by logical function not physical location. They manage bandwidth usage in networks by:
  • Enabling grouping high-bandwidth users on low-traffic segments.

  • Organizing users from different LAN segments according to their need for common resources and individual protocols.

  • Improving traffic control at the edge of networks by separating traffic of different protocol types.

  • Enhancing network security by creating subnets to control in-band access to specific network resources.

  • Cross-domain broadcast traffic in the switch is eliminated and bandwidth saved by not allowing packets to flood out all ports.

When configuring VLANs, you will need to plan your VLAN strategy as follows:

  1. Configure static VLANs with:
    • a name

    • VLAN ID number (VID)

    • port members

  2. Include port configuration planning to use dynamic VLANs.
  3. Create a map of the logical topology.
  4. Create a map of the physical topology.
  5. Consider the interaction between VLANs and other features:
    • Spanning Tree Protocol

    • port trunking

    • IGMP

  6. Configure at least one VLAN in addition to the default VLAN.
  7. Configure all ports that pass traffic for a particular subnet address on the same VLAN.
  8. Assign the desired switch ports to the new VLANs.
  9. Ensure that the VLAN through which you manage the switch has an IP address, if you are managing VLANs with SNMP in an IP network.

For information on the restrictions when you configure an IP address on a VLAN interface, see the "Comparing port based and protocol based VLAN" table in Static VLAN operation.