Introducing Ruckus Wireless ZoneDirector
Ensuring That APs Can Communicate with ZoneDirector
How APs Discover ZoneDirector on the Network
When an AP starts up, it sends out a DHCP
discovery packet to obtain an IP address.
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 serv
er that can help resolve the ZoneDirector
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 (li
ghtweight access point protocol) discovery
message to attempt to discover the pre-co
nfigured primary/secondary ZoneDirector.
An AP with a pre-configured ZoneDirector IP address will
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-confi
gured ZoneDirector, it will enter sulk state,
and will remain in an idle/dis
cover/sulk loop until it receives a response from a pre-
configured primary or secondary ZoneDirector.
If a primary/secondary ZoneDirector IP addr
ess has not been configured on the AP, the AP
next attempts to build a list of candidate Zone
Directors 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 fo
r a response from any ZoneDirector that can
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.
If the AP receives a response from a single Zo
neDirector device, it will attempt to register
with that ZoneDirector device.
If the AP receives responses from multiple Zo
neDirector devices, it will attempt to register
with the ZoneDirector that it prev
iously 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).
If this is the first time that the AP is register
ing with ZoneDirector, it will attempt to register
with the ZoneDirector device that has the lo
west AP load. The AP
computes the load by
subtracting the current number of APs regist
ered with ZoneDirector from the maximum
number of APs that ZoneDirector is licensed to support.
If the AP does not receive a response from an
y ZoneDirector device on the network, it goes
into idle mode. After a short period of time, t
he AP will attempt to discover ZoneDirector again
by repeating the same discovery cycle. The AP
will continue to repeat this cycle until it
successfully registers with a ZoneDirector