D-Link DWS-1008 - AirPremier MobileLAN Switch Product Manual page 129

2. If no IP addresses or hostnames were specified in the Option 43 field of the DHCP Offer
message, the AP sends a Find switch message to UDP port 5000 on the subnet broadcast
address.
• Switches in the same IP subnet as the AP receive the message and respond with a
Find switch Reply message.
• If the AP is configured as a Distributed AP on a switch and the connection
bias is high, the switch immediately sends a Find switch Reply message.
• If the AP is configured as a Distributed AP on a switch but the connection
bias is low, that switch waits one second, then sends a Find switch Reply
message. The delay allows switches with high bias for the AP to respond
first.
• If a switch that receives the Find switch message does not have the Distributed
AP in its configuration but another switch in the same network does, the
switch waits two seconds, then sends a Find Switch Reply message with
the IP address of the best switch to use. The determination of best switch is
based on the bias settings for the AP on each switch and on the capacity of
each switch to add new active AP connections.
The process skips to step 6.
• If no switches reply, the AP repeatedly resends the Find switch broadcast. If still no
switches reply, the process continues with step 3.
3. If the AP is unable to locate a switch on the subnet it is connected to, and is unable to find
a switch based on information in the DHCP option 43 field, the AP sends DNS requests for
both DLINK and wlan-switch, where the DNS suffix for mynetwork.com is learned through
DHCP.
Note: You must configure a DNS address record on your DNS server for the switch IP
address. Otherwise, the DNS server cannot provide the switch's address to the AP.
4. The DNS server replies with the system IP address of a switch.
• If only DLINK is defined in DNS, the AP sends a unicast Find switch message to the
switch whose IP address is returned for DLINK.
• If only wlan-switch is defined in DNS, the AP sends a unicast Find switch message
to the switch whose IP address is returned for wlan-switch.
• If both DLINK and wlan-switch are defined in DNS, the AP sends a unicast Find
switch message to the switch whose IP address is returned for DLINK. The AP
ignores the IP address returned for wlan-switch.
• If both DLINK and wlan-switch are defined in DNS, and the AP is unable to contact
the IP address returned for DLINK, the AP never contacts the IP address returned
for wlan-switch. The AP does not boot.
D-Link DWS-1008 User Manual 110