Layer 2 And Layer 3 Lwapp Operation; Operational Requirements; Configuration Requirements; Cisco Wireless Lan Controllers - Cisco SD2008T-NA Configuration Manual

Chapter 1 Overview

Layer 2 and Layer 3 LWAPP Operation

The LWAPP communications between Cisco Wireless LAN Controller and Cisco 1000 series
lightweight access points can be conducted at ISO Data Link Layer 2 or Network Layer 3.
The IPv4 network layer protocol is supported for transport through an LWAPP controller system. IPv6
Note
(for clients only) and AppleTalk are also supported but only on 4400 series controllers and the Cisco
WiSM. Other Layer 3 protocols (such as IPX, DECnet Phase IV, OSI CLNP, and so on) and Layer 2
(bridged) protocols (such as LAT and NetBeui) are not supported.

Operational Requirements

The requirement for Layer 2 LWAPP communications is that the Cisco Wireless LAN Controller and
Cisco 1000 series lightweight access points must be connected to each other through Layer 2 devices on
the same subnet. This is the default operational mode for the Cisco Wireless LAN Solution. Note that
when the Cisco Wireless LAN Controller and Cisco 1000 series lightweight access points are on
different subnets, these devices must be operated in Layer 3 mode.
The requirement for Layer 3 LWAPP communications is that the Cisco Wireless LAN Controllers and
Cisco 1000 series lightweight access points can be connected through Layer 2 devices on the same
subnet, or connected through Layer 3 devices across subnets. Another requirement is that the IP
addresses of access points should be either statically assigned or dynamically assigned through an
external DHCP server.
Note that all Cisco Wireless LAN Controllers in a mobility group must use the same LWAPP Layer 2 or
Layer 3 mode, or you will defeat the Mobility software algorithm.

Configuration Requirements

When you are operating the Cisco Wireless LAN Solution in Layer 2 mode, you must configure a
management interface to control your Layer 2 communications.
When you are operating the Cisco Wireless LAN Solution in Layer 3 mode, you must configure an
AP-manager interface to control Cisco 1000 series lightweight access points and a management interface
as configured for Layer 2 mode.

Cisco Wireless LAN Controllers

When you are adding Cisco 1000 series lightweight access points to a multiple Cisco Wireless LAN
Controller deployments network, it is convenient to have all Cisco 1000 series lightweight access points
associate with one master controller on the same subnet. That way, the operator does not have to log into
multiple controllers to find out which controller newly-added Cisco 1000 series lightweight access
points associated with.
One controller in each subnet can be assigned as the master controller while adding lightweight access
points. As long as a master controller is active on the same subnet, all new access points without a
primary, secondary, and tertiary controller assigned automatically attempt to associate with the master
Cisco Wireless LAN Controller. This process is described in the
Failover Protection" section on page
OL-9141-03
1-16.
Cisco Wireless LAN Controller Configuration Guide
Layer 2 and Layer 3 LWAPP Operation
"Cisco Wireless LAN Controller
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