Access Point And Controller Discovery - Avaya WLAN 8100 Series Quick Start Manual

Before you begin
The access point will use UDP port 61000 by default if Option 43 does not include the UDP
port number.

Access Point and Controller Discovery

The WLAN 8100 solution supports DHCP-assisted discovery and DNS-assisted discovery of
the controllers by the AP. The AP does not provide any interface for static configuration of the
network parameters such as IP address, subnet, default gateway, DNS or domain name. A
DHCP server must be configured in the network to assign these network parameters to the AP.
The AP obtains information about up to 4 controllers in the mobility domain from DHCP option
43 or DNS queries. For information on DHCP server configuration, refer to Avaya WLAN 8100
Quick Start Guide (NN47251–106).
If DHCP option 43 is not configured, the AP attempts to make DNS queries to resolve the
controller IP address. For the query the controller host name is assumed to be "wc1", "wc2",
"wc3" and "wc4". A fully qualified domain name is used whenever the DHCP response specifies
the domain name. Otherwise, unqualified controller host names are used. DHCP responses
should specify DNS server for the DNS assisted discovery mechanism.
Administrator must configure either "DHCP option 43" or DNS so that AP can obtain the IP
addresses of at least one active controller in the mobility domain. For redundancy in the
discovery process we recommend configuring at least two controllers on DHCP server or DNS.
When both DHCP option 43 and DNS servers are configured, an AP attempts connection with
controller IP's determined from DHCP options before attempting to connect to those
determined from DNS queries.
The access points will do a DHCP query again if they cannot obtain a controller IP from DHCP/
DNS or do not get any response from the controller IP determined from the DHCP/DNS. This
allows the administrator to recover from incorrect configuration of DHCP server or DNS.
A controller accepts an AP only when the MAC address of the AP is present in the domain AP
table of the controller and there are AP licenses available. If the AP MAC address is not
configured in the domain AP table of the controller then the AP is reported as a newly
discovered AP to the active MDC and it should show up in the discovered AP table. However,
only AP(s) that have been configured to be part of domain AP table can be managed by the
mobility domain.
From the perspective of the controller, the AP has the following states:
• Discovered – AP has sent a connection request to the controller and controller validated
the AP against the domain AP table.
• Authenticated – AP has authenticated with the controller and in the process of applying
configuration received from the controller.
• Managed – AP has successfully applied the configuration and its radios are not
operational.
• Failed – An AP that was previously managed by the controller has left the controller.
6 Avaya WLAN 8100 Quick Start Guide August 20, 2010