Wireless LAN Basics | Cisco Access Points

WLAN Basics

There are certainly a number of different options available when looking to implement a Cisco Wireless LAN (WLAN). The vendor that is selected often has a lot to do with the different features that are supported and how the devices can be integrated into a common network management environment. Cisco has a number of wireless solutions that offer support for a number of different environments, including their new second generation access point (AP) portfolio. This article takes a look at the available Cisco second generation wireless APs along with the features that can be supported with these offerings.

Most of Cisco’s AP lines offer the ability to operate in one of two modes: standalone (autonomous) or controller-based. Those APs that operate in standalone mode operate much like common home wireless APs; all of the wireless control functions and radio management is done via a single device. AP’s that operate in controller-based mode handle wireless functions while offloading much of the management and control decisions to the wireless controller. A general understanding of this is important going into the next section because some features are only supported with APs that are functioning in one mode or the other.

Cisco Wireless Features

As with all vendors, Cisco has a number of different features that it references, some of which can be clear in their function from their names, and some that are not as clear. The following subsections with go over some of the most common features.

OfficeExtend

Cisco’s OfficeExtend feature provides an easy to deploy remote office solution while supporting a high speed wireless connectivity solution for remote workers. The OfficeExtend feature requires the use of a controller-based deployment because the remote AP’s are pre-configured (by the corporate networking staff) to automatically connect and set up an encrypted tunnel between the remote location and a central controller. This tunnel is then used by the remote worker to perform their duties the same way they would if they were physically at the central location.

ClientLink

The ClientLink feature is targeted at those environments that must support a number of different wireless client types. One common problem that wireless network engineers have to deal with is how to support these clients (802.11n vs 802.11a, b or g). This is referred to as wireless mixed mode (where the APs must support multiple wireless standards) and can cause a large bottleneck in the performance of a wireless network. The ClientLink feature works by optimizing the available APs so that all clients are able to get the best available upstream and downstream connection.

CleanAir

The CleanAir feature was designed to help deal with the shared spectrum that wireless networks must utilize. The CleanAir feature works system-wide by monitoring and tracking the sources of interference throughout the network; this information can then be used to optimize the coverage of the operating APs. This feature also provides the ability to automatically self-heal by monitoring when interference sources become large enough to cause service disruption. In these situations the system will change the channel assignments to avoid this interference.

Second Generation AP’s

There are four different AP lines which are considered part of Cisco’s second generation; these will be covered briefly in the next few sections.

Aironet 600

The Aironet 600 is a dual-band (2.4/5 GHz) AP that was designed specifically for the remote worker environment; it can be easily pre-configured for a simple plug-in configuration for the remote worker assuming an existing Internet connection exists.

Aironet 1600

The Aironet 1600 is an entry level AP with support for IEEE 802.11n 3×3 MIMO with 2 spatial streams (up to ~300 Mbps). As of this writing, the 1600 Series does not have support for the CleanAir feature but does support most other Common Cisco features (including support for 32 ClientLink clients).

Aironet 2600

The Aironet 2600 is optimized for mixed mode environments but can be deployed in any AP role in all locations. It supports IEEE 802.11n 3×4 MIMO with 3 spatial streams (up to ~450 Mbps). It also supports all of Cisco’s features (including support for 128 ClientLink clients).

Aironet 3600

The Aironet 3600 supports all of the same features and functions as the Aironet 2600 with support for IEEE 802.11n 4×4 MIMO with 3 spatial streams (~up to 450 Mbps) but also adds some additional future proofing with support for IEEE 802.11ac (Up to 1.3 Gbps) or the WSSI (Wireless Security and Spectrum Intelligence) Module.

Summary

While Cisco is only one of many in the wireless networking arena they are a major player and should be looked over along with other solutions to find the best match both technically and fiscally for each specific situation.

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