HP ProCurve 520wl Wireless Access Point - Manual (Page 91)

Advanced Configuration
VLAN Workgroups and Traffic Management
Access Points that are not VLAN-capable typically transmit broadcast and multicast traffic to all wireless Network
Interface Cards (NICs). This process wastes wireless bandwidth and degrades throughput performance. In
comparison, VLAN-capable AP is designed to efficiently manage delivery of broadcast, multicast, and unicast traffic to
wireless clients.
The AP assigns clients to a VLAN based on a Network Name (SSID). The AP can support up to 16 VLAN/SSID pairs
per radio (based on model type).
NOTE
16 VLAN/SSID pairs are available for APs with an HP ProCurve Wireless 802.11g AP Card 170wl only.
The AP matches packets transmitted or received to a network name with the associated VLAN. Traffic received by a
VLAN is only sent on the wireless interface associated with that same VLAN. This eliminates unnecessary traffic on
the wireless LAN, conserving bandwidth and maximizing throughput.
Traffic Management
In addition to enhancing wireless traffic management, the VLAN-capable AP supports easy assignment of wireless
users to workgroups. In a typical scenario, each user VLAN represents a workgroup; for example, one VLAN could be
used for an EMPLOYEE workgroup and the other, for a GUEST workgroup.
In this scenario, the AP would assign every packet it accepted to a VLAN. Each packet would then be identified as
EMPLOYEE or GUEST, depending on which wireless NIC received it. The AP would insert VLAN headers or “tags”
with identifiers into the packets transmitted on the wired backbone to a network switch.
Finally, the switch would be configured to route packets from the EMPLOYEE workgroup to the appropriate corporate
resources such as printers and servers. Packets from the GUEST workgroup could be restricted to a gateway that
allowed access to only the Internet. A member of the GUEST workgroup could send and receive e-mail and access the
Internet, but would be prevented from accessing servers or hosts on the local corporate network.
Typical User VLAN Configurations
VLANs segment network traffic into workgroups, which enable you to limit broadcast and multicast traffic. Workgroups
enable clients from different VLANs to access different resources using the same network infrastructure. Clients using
the same physical network are limited to those resources available to their workgroup.
The AP can segment users into a maximum of 16 different workgroups (32 if using two cards in a Dual-radio AP)
based on an SSID/VLAN pair (also referred as a VLAN Workgroup or a Sub-network).
NOTE
16 VLAN/SSID pairs are available for APs with an HP ProCurve Wireless 802.11g AP Card 170wl only.
The four primary scenarios for using VLAN workgroups are as follows:
1. VLAN disabled: Your network does not use VLANs, but you can configure the AP to use multiple SSIDs.
2. VLAN enabled, all VLAN Workgroups use the same VLAN ID Tag
3. VLAN enabled, each VLAN workgroup uses a different VLAN ID Tag
4. VLAN enabled, a mixture of Tagged and Untagged workgroups
4-49