A note about speeds

The handheld analyzers were limited in looking at 802.11b because the higher speeds of 802.11a are simply too fast for the PC Card data bus used in the most popular form factor – HP’s iPAQ 3800 Series.

The handheld analyzers were limited in looking at 802.11b because the higher speeds of 802.11a are simply too fast for the PC Card data bus used in the most popular form factor – HP’s iPAQ 3800 Series. The current crop of 802.11a/g cards are based on CardBus – the PCI bus-like superset of the PC Card specification. Only now are handhelds starting to emerge that can support CardBus adapters’ data rates. CardBus also will be necessary for 802.11g’s proposed (but rarely achieved) 54M bit/sec data rates. Network Instruments recently announced an update to its Observer Wireless notebook-based product that will support 802.11a/b/g and no doubt require a CardBus interface (and likely will need updates as contentions in the final standard are worked out).

The notebook PC-based analyzers are the only platform for analysis of 802.11a (in addition to b). Normally, a notebook uses only one of the two available wireless LAN connectivity methods (a or b). A WLAN analyzer must flip between these modes to gauge both protocols sequentially, although all but one notebook analyzer (AirMagnet) we tested could test only one protocol at a time.

Notebook-based analyzer software makers have often adapted their network analysis offerings by adding WLAN extensions, probes or other attachments – thus turning them into products thought to be only for the WLAN analysis market. We found mixed results in this architecture because WLAN analysis needs a strong focus on the radio.

Back to main review: “WLAN analyzers”