WLAN

Opportunities and challenges for WLAN 

Traditional cabled networks do not allow flexible accesses due to restrictions on wiring resources. With the increasing popularity of mobile terminals (tablet computers and smart phones) among enterprises, WLAN is increasingly becoming an important part of a corporate access network. The main challenges for the design and deployment of a WLAN include: wireless security, radio signal stability (radiofrequency interferences), wireless roaming and manageability.

 

WLAN solution 

Collectively controlled WLAN 

As each wireless access point (AP) of the traditional WLAN (fat AP) is an independent node, various wireless APs need to have independent settings for RF channel, power, certification, encryption and network parameters. Therefore, it is impossible for collective RF signal management, security control and network administration and it is very hard to realize large-scale, continuous and coordinated WLAN and add advanced applications. 

A collectively controlled wireless network is needed in order to eliminate these restrictions, i.e. a network that is based on WLAN controller-connected light-weight access point (fit AP). This deployment is expected to realize the separation of wireless access and management and make it easier for wireless network expansion, dynamic RF management, L3 roaming, positioning services and other advanced applications (e.g. WLAN voices, IDS, etc). The diagram of the collectively controlled wireless network is as follows:

 

 

Figure 1

 

Benefits of collective control

A collectively controlled wireless network enables dynamic RF management. The wireless controller can sense the RF channel and power conditions around each AP and performs dynamic adjustments in order to guarantee isolations between adjacent APs. Meanwhile, the wireless controller can adjust the power of adjacent APs when any particular AP has a fault so as to realize seamless coverage and substantially increase the stability of RF signals.

A collectively controlled wireless network enables better security controls. The access to all wireless terminals needs to be generically certified by the wireless controller. All transmitted data needs to be connected to the wireless controller via an encrypted channel and filtered by the wireless controller or any external firewall before they are forwarded to the internal network of the enterprise. Coupled with the 128-digit or higher dynamic encryption key and algorithm, it can fully guarantee the confidentiality of the transmitted data. 

A collectively controlled wireless network makes it easier for seamless roaming. All user status data (including certification data, QOS, ACL, etc) are kept in the wireless controller. When the user roams from one AP to another, network access is possible without complicated processes. 

A collectively controlled wireless network is easier to administer. There is no need to independently configure any AP. Instead, they are collectively configured and administered by the wireless controller. As a result, a higher degree of scalability and manageability becomes possible.

 

Corporate WLAN solution 

In addition to the deployment of wireless controllers and APs as part of a corporate WLAN, one wireless trunk network may also be established via Mesh technology which is connected to various APs for expansion of the wireless network where wiring resources are restricted. Moreover, for mobile office users, VPN-enabled APs may also be adopted to conveniently and readily connect them into the corporate network at any time. The schematic diagram of the corporate WLAN solution is as follows:

 

Figure 2

 

Conclusions 

As an important supplement to the cabled network, wireless networks will increasingly become an important constituent of a corporate access network. With the progress of wireless certification and encryption technologies, the security of a wireless network has been substantially improved and can already satisfy the needs of commercial access networks. The introduction of the collective control management model will further improve the security, stability, scalability and manageability of the wireless network.