Cisco Cisco 2000 Series Wireless LAN Controller Guia De Resolução De Problemas
Note:
By default both management and AP-manager interfaces are left untagged on their VLAN during
configuration. In case these are tagged, make sure they are tagged to the same VLAN in order to properly
receive discovery and join response from the WLC.
receive discovery and join response from the WLC.
The LWAPP AP goes through this process on startup for Layer 3 mode:
The LAP boots and DHCPs an IP address if it was not previously assigned a static IP address.
1.
The LAP sends discovery requests to controllers through the various discovery algorithms and builds
a controller list. Essentially, the LAP learns as many management interface addresses for the
controller list as possible via:
a controller list. Essentially, the LAP learns as many management interface addresses for the
controller list as possible via:
DHCP option 43 (good for global companies where offices and controllers are on different
continents)
continents)
a.
DNS entry for
cisco-capwap-controller
(good for local businesses - can also be used to
find where brand new APs join)
Note:
If you use CAPWAP, make sure that there is a DNS entry for
cisco-capwap-controller
.
b.
Management IP addresses of controllers the LAP remembers previously
c.
A Layer 3 broadcast on the subnet
d.
Over the air provisioning
e.
Statically configured information
f.
From this list, the easiest method to use for deployment is to have the LAPs on the same subnet as the
management interface of the controller and allow the LAP’s Layer 3 broadcast to find the controller.
This method should be used for companies that have a small network and do not own a local DNS
server.
management interface of the controller and allow the LAP’s Layer 3 broadcast to find the controller.
This method should be used for companies that have a small network and do not own a local DNS
server.
The next easiest method of deployment is to use a DNS entry with DHCP. You can have multiple
entries of the same DNS name. This allows the LAP to discover multiple controllers. This method
should be used by companies that have all of their controllers in a single location and own a local
DNS server. Or, if the company has multiple DNS suffixes and the controllers are segregated by
suffix.
entries of the same DNS name. This allows the LAP to discover multiple controllers. This method
should be used by companies that have all of their controllers in a single location and own a local
DNS server. Or, if the company has multiple DNS suffixes and the controllers are segregated by
suffix.
DHCP option 43 is used by large companies to localize the information via the DHCP. This method is
used by large enterprises that have a single DNS suffix. For example, Cisco owns buildings in
Europe, Australia, and the United States. In order to ensure that the LAPs only join controllers locally,
Cisco cannot use a DNS entry and must use DHCP option 43 information to tell the LAPs what the
management IP address of their local controller is.
used by large enterprises that have a single DNS suffix. For example, Cisco owns buildings in
Europe, Australia, and the United States. In order to ensure that the LAPs only join controllers locally,
Cisco cannot use a DNS entry and must use DHCP option 43 information to tell the LAPs what the
management IP address of their local controller is.
Finally, static configuration is used for a network that does not have a DHCP server.You can statically
configure the information necessary to join a controller via the console port and the AP’s CLI. For
information on how to statically configure controller information using the AP CLI, refer to Manually
Configuring Controller Information Using the Access Point CLI.
configure the information necessary to join a controller via the console port and the AP’s CLI. For
information on how to statically configure controller information using the AP CLI, refer to Manually
Configuring Controller Information Using the Access Point CLI.
For a detailed explanation on the different discovery algorithms that LAPs use to find controllers,
refer to LAP Registration with WLC.
refer to LAP Registration with WLC.
For information on configuring DHCP option 43 on a DHCP server, refer to DHCP OPTION 43 for
Lightweight Cisco Aironet Access Points Configuration Example.
Lightweight Cisco Aironet Access Points Configuration Example.
2.
Send a discovery request to every controller on the list and wait for the controller's discovery reply
which contains the system name, AP-manager IP addresses, the number of APs already attached to
each AP-manager interface, and overall excess capacity for the controller.
which contains the system name, AP-manager IP addresses, the number of APs already attached to
each AP-manager interface, and overall excess capacity for the controller.
3.
Look at the controller list and send a join request to a controller in this order (only if the AP received
a discovery reply from it):
a discovery reply from it):
4.