Ruckus Wireless ZoneDirector 3000, User Manual, Page: 31 / 430

Ensuring That APs Can Communicate with ZoneDirector
How APs Discover ZoneDirector on the Network
ZoneDirector 9.8 User Guide, 800-70599-001 Rev B
31
How APs Discover ZoneDirector on the Network
1 When an AP starts up, it sends out a DHCP discovery packet to obtain an IP
address.
2 The DHCP server responds to the AP with the allocated IP address. If you
configured DHCP Option 43 (see
Option 2: Customize Your DHCP Server ), the
DHCP offer response will also include (among others) the IP addresses of
ZoneDirector devices on the network along with the address of the DNS server
that can help resolve the ZoneDirector IP addresses.
3 After the AP obtains an IP address, it first attempts to contact a ZoneDirector
whose IP address has been pre-configured on the AP. If an AP has a pre-
configured ZoneDirector IP address, it will always use an L3 LWAPP (lightweight
access point protocol) discovery message to attempt to discover the pre-
configured primary/secondary ZoneDirector.
• An AP with a pre-configured ZoneDirector IP address will only attempt to
discover the pre-configured ZoneDirector(s) and will skip the DHCP/DNS/last
joined ZoneDirector steps. If it is unable to contact its pre-configured Zone-
Director, it will enter “sulk” state, and will remain in an idle/discover/sulk loop
until it receives a response from a pre-configured primary or secondary
ZoneDirector.
4 If a primary/secondary ZoneDirector IP address has not been configured on the
AP, the AP next attempts to build a list of candidate ZoneDirectors by sending
an L3 discovery request (IPv4 subnet broadcast/IPv6 multicast packet) to each
candidate address received from DHCP and DNS at the same time, and waits
for a response from any ZoneDirector that can respond.
• The AP may receive multiple responses from DHCP and DNS if multiple
ZoneDirector IP addresses have been configured on the DHCP server or DNS
server.
5 If the AP receives a response from a single ZoneDirector device, it will attempt
to register with that ZoneDirector device.
6 If the AP receives responses from multiple ZoneDirector devices, it will attempt
to register with the ZoneDirector that it previously registered with (if any).
• This ZoneDirector can be on the same local IP subnet or a different subnet. The
AP will have a preference for a ZoneDirector device that it previously registered
with (over a locally connected ZoneDirector).