D-Link DWS-3024 [61/266] Discovery and peer switches

Software User Manual D-Link Unified Access System

02/15/2011

Document 34CS3000-SWUM104-D10 Page 61

This discovery method only works if you configure the DHCP option before the AP receives its network information from the

DHCP server.

For information about how to configure option 43 with the IP address of one or more Unified Switch, see “Setting the Switch

Information in the DHCP Option” on page 69.

Discovery and Peer Switches

When multiple peer switches are present in the network, you can control which switch or switches are allowed to discover a

particular AP by the discovery method you use.

If you want to make sure that an AP is discovered by one specific switch, use one of the following methods:

• Disable L2 Discovery on all switches and configure the IP address of the AP in only one Unified Switch.

• Configure the IP address of one Unified Switch in the AP.

• Configure the DHCP option 43 with the IP address of only one Unified Switch.

An alternative approach is to configure the RADIUS server to return a switch IP address during AP MAC address checking

in the AP authentication process. For information about how to configure the RADIUS server to return a switch IP address,

see Appendix Appendix B:, <Link>“Configuring the External RADIUS Server” on page 207.

If the RADIUS server indicates that the AP is a valid managed AP and returns an IP address of a switch that is not the same

as this switch, then the switch sends a “re-link” message to the access point with the IP address of the Unified Switch to

which the AP should be talking to. When the AP gets the re-link message it modifies or sets the Unified Switch IP address,

breaks the TCP connection with the current switch and starts a new discovery process.

You can configure the D-Link Unified Access System so that each AP is allowed to be managed by any of the four switches

in a peer group. If the Unified Switch that manages an AP goes down, one of the backup switches takes over the

management responsibilities.

To use one or more peer switches as a backup for an AP, use one of the following discovery methods:

• If the AP and any of the peer switches are in the same L2 broadcast domain, L2 Discovery is enabled, and all the

devices use the default VLAN settings, a peer switch will automatically discover the AP if the primary Unified Switch

becomes unavailable.

• Configure the IP address of the AP in up to four switches.

• Connect to the access point CLI and configure the IP address of up to four switches.

• Configure the DHCP option 43 with the IP address of up to four switches in a peer group.

Assigning the IP Address to Switches and Managed APs

D-Link Unified Switches communicate with each other and with D-Link Access Points by using the IP protocol, so each

device must have a valid IP address.

D-Link Unified Switch with Routing Disabled

If routing is disabled on the D-Link Unified Switch, it uses the network interface address of the switch that you configured

during the initial setup process.

Note: If you change the IP address of the network interface, the wireless function on the switch automatically

disables and re-enables. If you used DHCP for the IP address assignment, make sure the lease does not expire.