Wireless LAN Controller in the Private Cloud

wlancontroller_rsserieWhether it’s the residential sector or comprehensive installations within offices, to highly sophisticated applications and even beyond, by now wireless networks can be found in almost all market segments. Wireless LAN has become far more than a mere network to supply wireless Internet connectivity. The technology is now part of a business processes. Due to the large variety of applications, it is hard to mention all of them. Nevertheless, these are the most common applications. The wireless Internet access and e-mail connection are the most common applications for sure. Some companies have even stopped using LAN cabling to a great extent. Retailers often use mobile cash registers connected via wireless LAN. Logistic companies, as well as retailers, register incoming and outgoing goods by wireless barcode scanners. And while we are on the subject of retailers and logistic companies, they nearly always have several locations and hence they are chain stores.

Today’s wireless LAN networks have become increasingly available throughout the entire company infrastructure. Therefore a variety of access points are required for a seamless network and of course, for a central management and monitoring of sometimes numerous access points, wireless LAN controllers are used.

Wireless LAN controller for chain stores and branch offices: Centralized management

We will now describe the suitability of wireless LAN controllers for chain stores in order to facilitate the monitoring and configuration of wireless LAN networks in different branches. Thus the central management and monitoring of all access points in all branches should be prioritized.

Working via a WAN connection a wireless LAN controller in remote operation, secured via a VPN tunnel, has some specific characteristics.


In the graph above the wireless LAN controller located at the central site communicates via a secured VPN connection to numerous access points which are located in several branches.

These access points in the graph above are fat access points. Basically the wireless LAN controller centralizes configuration and monitoring. It is advantageous to process the user data in the various branches locally in order to limit the data volume transferred via the WAN connection secured by VPN. This is the case in many applications. Initially, as a fail-safe operation, a supermarket chain for example, usually processes on site and hence decentralizes the data of the supermarket checkouts and wireless barcode scanners. Only in the evening at closing time data synchronization takes place between the branches and the Head Office.

Wireless LAN controller solutions for remote operations

A further problem which occurs with the remote operation of a wireless LAN controller, is the availability of a WAN connection secured via VPN. Naturally a VPN connection cannot guarantee a hundred percent availability. Even managed VPN services only assure an availability that ranges between 95 and 98 percent. After all this could mean a failure of several days a year.

Hence, it can be said that, only wireless LAN controller solutions that are especially designed for remote operations are suitable for this type of scenario. This includes:

  • Traffic limitation between access points and the wireless LAN controller.
  • Self-sufficient operation of access points that can run for a specific period of time without being connected to the wireless LAN controller.
  • Users should make sure that the data can be processed locally in order to bridge downtimes of the VPN connections.

Bintec WLAN products can deliver a simple and powerful platform that solves common problems such as reliability, security and local/remote management of the whole WLAN network across the WAN and individual Access Points. Total integration with Teldat or bintec-elmeg routers and management platforms is indeed a strong added value for those customers who already have a significant installed base of these devices. Moreover, it is also a great added value for those who plan to deploy a large number of branch office infrastructure and need a complete network solution for wired and wireless connectivity.

Hans-Dieter Wahl: WLAN Business Line Manager

What to expect from 802.11ac. Has the moment for enterprise networks arrived?

WLAN-150x150Currently there is a lot of noise in the press regarding the new so called Gigabit 802.11 ac standard. Of course the upgrade to 802.11 ac has some technical advantages, but even though, is now the right time to upgrade your enterprise network or is the new technology not yet finalized?

It is important to consider for this analysis company requirements, as it is the market to which Teldat products are focused towards. Whilst within a home/SoHo environment, one Access Point has to serve a small number of WLAN clients with excellent performance, in a typical enterprise application we will have a large number of Access Points to cover a large office area and the main need will be to serve a large number of roaming clients, unevenly distributed. This will be sufficient with a good average WI-FI performance.

802.11ac operates exclusively on the 5GHz network, but is backward compatible with the existing clients. Current chipsets promise data rates of up to 1.3 Gbit / s – this is the physical rate, whilst the net rate is about 50% lower. The performance gain is achieved mainly by two improvements. Firstly, instead of 20MHz channel bandwidth, 11 ac requires at least 80 MHz, and there is even a variant which requires 160 MHz of bandwidth. However, this very high bandwidth requirement complicates an overlap-free (and thus interference-free) channel planning within companies. Depending on the channel bandwidth, only one or two channels in the Indoor-frequencies bands are used. So especially due to the high channel bandwidth, it may well be that bottlenecks in enterprise networks are generated, as they tend to have many access points and many clients in each channel. Thereby less wireless clients can connect simultaneously to the Wi-Fi network. This could cause a huge problem for business networks.

The second improvement is that in addition to the 64-level quadrature modulation (64-QAM) it will now be adding a 256-level quadrature modulation (256-QAM). However, the use of 256-QAM requires a very good signal-to-noise ratio, which is only achieved at short distances to the access point. If the signal-to-noise ratio is not adequate, the devices switch back to 64-QAM.

An important point is the economic aspect. A possible migration to .11 ac should analyse the network infrastructure, as well as the costs involved in the planning. The current .11 ac devices are very power hungry and require a higher PoE power class (802.3at) – hence new switches will need to be purchased. In addition, the first .11 ac products are considerably more expensive than the best .11 n devices.
The new .11 ac standard comes with another technical improvement which is very important in raising the performance for many clients, especially enterprise networks. This feature is called MU-MIMO (Multi-User MIMO). Without MU-Mimo all 1×1 Mimo clients will always share the first stream or antenna of an Access Point (E.g. when connecting three 1×1 Mimo clients to a 3×3 MIMO Access Point). For MU-MIMO however, each client can receive its own stream from the access point. That means the system has a three times higher throughput or each Access Point can serve three times more clients. In any case a significant improvement.

MU-MIMO is therefore particularly interesting for applications in enterprises, as it is in this case less concerned with providing a single client with the highest possible data throughput, and is more concerned about connecting as many users with the best possible performance. The MU-MIMO is not yet in the current available chipsets – this is the most significant reason why 802.11 ac is still not quite ready for business use.

The R&D department at Teldat works closely together with semiconductor manufacturers and the latest technologies available, to launch in the next months a dual-radio enterprise access point that combines the advantages of 2.4 GHz .11 n technology and the new .11 ac technology together. This next-generation .11 ac will be both more efficient with energy consumption, as well as in the use of mobile .11 ac terminals.

Hans-Dieter Wahl: WLAN Business Line Manager