HP Wireless Networking
A wireless local area network (WLAN) provides computer connectivity to network resources without the use of cables. Wireless communications are useful in locations where the cost of introducing cabling is prohibitive or for laptop users to temporarily connect to a network. At the centre of the WLAN are one or more Wireless Access Points (sometimes referred to as APs) which act as radio wave transmitters over which network traffic is carried. Each client computer wishing to access the WLAN requires a wireless network card. In addition, the wireless access point will have a wired network connection to the remainder of the network.
Standards - there are several connection standards based upon the original IEEE 802.11 specification which have evolved over time (these are described in detail at http://en.wikipedia.org/wiki/IEEE_802.11). The table below explains the differences between the most popular versions.
| Standard | Adoption Date | Max Connection Speed | Maximum Range |
|---|---|---|---|
| 802.11b | 1999 | 11Mb/s | 140 metres |
| 802.11g | 2003 | 54Mb/s | 140 metres |
| 802.11n | 2009 | 150Mb/s | 250 metres |
NOTE: When evaluating equipment it is important to consider backwards compatibility between these different standards as many client computers have older 802.11b / g network cards. Some modern 802.11n access points are not compatible with these devices, so be careful (all Modrus recommended solutions are compatible).
Number of Radio Transmitters - the maximum number of clients which are able to connect to an access point is determined by the bandwidth supported by its transmitter (this varies by manufacturer but is typically around 50-60 clients). In order to overcome this, some access points have two or even three transmitters (also known as radios) 
thus increasing the maximum number of clients. Some access points also allow different standards to be broadcast over each radio, i.e. you can run 802.11 b / g from one and 802.11n from another - thus facilitating backwards compatibility.
Access Security & Data Encryption - early wireless networking security implementations were poor with simple passwords required to gain access. This did not match the requirement for more stringent security needed for corporate implementations and hence over time more sophisticated security functionality (which seamlessly integrates with standard wired network security systems such as Active Directory and Radius) have evolved. In addition, the data being transferred across WLAN connections is now encrypted, meaning that it is useless if intercepted by a third party.
NOTE: Some HP wireless access points allow one of their radios to be used as an RF (radio frequency) detector, which in conjunction with specialist management software can be used to detect unauthorised networks and intrusions into legitimate networks, more of this later.
Management - in a small organisation the management of a single access point is not a major overhead, however in a large enterprise with many access points, this can be a significant issue. As a result the trend has been for access points themselves to become "dumbed down" and for all management and user traffic to be routed back to a centralised WLAN Switch situated at the core of the network.
The benefit of doing this is that there is now a single place where all access point configuration needs to be carried out, however it also creates a bottleneck through which all WLAN traffic is routed. This is problemmatic because of...
- Application latency
- Single point of failure
- Inefficient use of the infrastructure
HP's WLAN architecture uses "distributed forwarding" to allow traffic to flow directly from source to destination without taking an extraneous round trip through the centralised WLAN switch or the network core. This design eliminates needless traffic through the WLAN switch and LAN backbone, enabling users to enjoy better performance and faster, more-responsive applications. It is a necessary feature for real-time applications such as voice, which are particularly vulnerable to latency.
Local Mesh - a local mesh extends your network across multiple access points. In this way you can provide network services in extended areas without Ethernet cabling. This is especially useful in cases where laying cable is difficult or impossible - for example, when connecting two sites more than 150 metres apart, or when extending coverage outdoors. Common locations for wireless meshes include hotels, factories, hospitals, outdoor campuses and sports arenas. HP supports 'dynamic' local meshes, which automatically reconfigure themselves to maintain connectivity if any single AP in the local mesh fails.
The local mesh extends the range of the WLAN.