Cisco Unified Wireless Network (CUWN)

CUWN was introduced to address the following challenges:

• Integrating device types so that they work well together
• Ensure a consistent security configuration despite increasing numbers of APs
• Monitoring environment for new sources of interference and redeploy if necessary
• Managing channel allocation to minimise co and adjacent channel interference

CUWN elements - Clients, APs, Network Unification (devices which join wired and wireless networks; WiSM, WLCM), Network Management, Network Services (IDS and admission control)

LWAPP (Lightweight access point protocol) is used to carry data between the APs and WLC. It carries and encapsulates control information over an encrypted tunnel. It encapsulates frames with a 6 byte header which also contains the RSSI and SNR information. Another header is then added with the source and destination address (AP and WLC address). LWAPP operates in L2 or L3 mode, in L2 mode only the MAC addresses are used. Because of this overhead the wireless packets are larger than 1500 bytes, usually 2346 bytes. The fragmentation field for the LWAPP header watches this, the fragments are called segments. 

WCS facilitates the management of several WLC. It is also required for location services (tracking and RFID tags) using the location appliance.

Split MAC is the ability to split 802.11 data link functions between the AP and WLC. The AP handles time real time communication and the WLC handles non-time sensitive. 

Real time Traffic is:

Frame handshake exchange between client and AP done during each frame transfer

Handling of frames for clients in power save mode

Beacon transmission

Responses to probe requests

Real time signal quality information for each received frame

RF channel monitoring including noise, interference, other WLANs and rouge APs

Encryption and decryption, excluding VPN and IPSec clients (Layer 2 wireless)

Non-time sensitive traffic:

802.11 authentication

802.11 association and re-association; also known as mobility

802.11 to 802.3 bridging

The point where all 802.11 frames  terminate at the controller