Cisco completed its acquisition of a company called Airespace in early 2005. Now, the new Cisco 1000 Series Lightweight AP and WLAN controllers are included in its Wi-Fi catalog. These components work in tandem to deliver easy setup and configuration and a robust radio frequency (RF) environment.
Cisco 1000 Series Lightweight AP
This device has its benefits. It can be installed and connected to the network, with no configuration or setup needed on the AP, because configuration data is downloaded to the thin AP from a WLAN controller. This device is shown in Figure 1-9.
Figure 1-9. Cisco 1000 Series Lightweight AP
Although its easy installation and setup are big selling points for this device, it does much more. Because the AP's functioning is somewhat centralized to the WLAN controller, the AP can feed information about the RF environment back to the WLAN controller and the Cisco Wireless Control System. This allows these applications to make real-time decisions.
The data is forwarded and the RF environment monitored, which eliminates the need for additional nodes dedicated to those management functions. In turn, the overall network design is much simpler and more cost efficient. Within the 1000 series are three models:
The 1000 series allows power over Ethernet connections and over the air QoS.
The 1000 series also operates using 802.11a and 802.11g radios, affording compatibility with both standards and operation on up to 15 nonoverlapping channels.
Cisco WLAN Controllers
Earlier, we discussed the lines of the Cisco Lightweight APs. The APs and wireless control system are two legs of a three-legged stool; WLAN controllers comprise the other.
WLAN controllers are the hub of systemwide WLAN operation. They are the devices on which information is stored and disseminated to thin APs. In return, environmental data is sent back to the WLAN controller for analysis and action. The information stored on the WLAN controllers includes:
WLAN controllers communicate with the thin APs over Layer 2 or Layer 3 infrastructure using the Lightweight Access Point Protocol (LWAPP). This protocol ensures that communication between WLAN controllers and thin APs is secure.
Cisco offers three series of WLAN controllers: the 2000 Series, the 4100 Series, and the 4400 Series.
The Cisco 2000 Series WLAN controller is targeted at small- to medium-sized enterprise applications. Its 2006 model is capable of controlling up to 6 thin APs. The 2000 is shown in Figure 1-10.
Figure 1-10. Cisco 2000 Series WLAN Controller
The Cisco 4100 Series WLAN controller is targeted at medium- to large-sized enterprise applications. Its three modelsthe 4112, 4124, and 4136offer support to 12, 24, or 26 thin APs, respectively. This series features dual Gigabit Ethernet uplinks for LAN connectivity. The 4100 Series is shown in Figure 1-11.
Figure 1-11. Cisco 4100 Series WLAN Controller
These WLAN controllers can detect and adapt to changes in the RF environment. This level of management affords the following functionality:
WLAN controllers use up-to-date security features that include WPA2, WPA, WEP, multiple EAP types, and a VPN termination module for IPSec and Layer 2 Tunneling Protocol.
Other security features include:
Because the WLAN controller operates at both Layer 2 and 3 levels, users can roam among APs, switches, and routed subnets without interruption in service. In addition, security and QoS information follows them, so the operation environment is consistent.