D-Link DWS 3000 Discovery and Peer Switches, Assigning the IP Address to Switches and Managed APs

D-Link Unified Access System User Manual

The AP can learn up to four WCS IP addresses or DNS names through DHCP option 43 in the DHCP response.

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 WCS, 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 WCS.

•Configure the IP address of one WCS in the AP.

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

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 B, “Configuring the External RADIUS Server” on page 179.

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 wireless switch to which the AP should be talking to. When the AP gets the re-link message it modifies or sets the wireless 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 WCS 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 WCS 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 WLAN Controller Switchs communicate with each other and with D-Link Access Points by using the IP protocol, so each device must have a valid IP address.

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