Fluke's EtherScope has been around for a little while now as a troubleshooting tool for wired Ethernet networks. Now the company has added support for 802.11a/b/g wireless Ethernet, creating the EtherScope Wireless Network Assistant.
EtherScope WNA is not merely a connectivity tester, it's a laptop-sized problem solving tool that can tell you all sorts of things about your network and the radio frequency environment.
It has several uses, the first being ad hoc discovery of access points and wireless clients (though not unconnected infrastructure clients), either passively or actively. Its signal strength meter can be used to locate devices, you will have to do your own triangulation though.
It can also measure RF usage, including per-channel usage and signal quality - the issues here are very similar to those on wired networks, but of course on wireless there are several channels, so you want to see who is taking bandwidth and where the RF noise is. You can set thresholds for problem notification, and channel usage can be broken down by frame type, retries, errors and so on..
A third use is to do security scans for unprotected or open wireless LANs, unauthorised devices, access points broadcasting their SSID or transmitting on the wrong channel, and so on. However, it's probably best not to rely on manual scans such as this as your main way to detect rogue access points - if your users get wise to them, they will simply turn the unauthorised gear off as soon as you appear.
EtherScope does reporting, and you can save reports (to a CompactFlash memory card, in XML format) so you can use them to document your WLAN. This can also be useful for site surveys, because it means you can compare the new WLAN map with a previous one.
And it can measure network speed from point to point, though to do this properly requires two EtherScopes. It has a trace switch route function as well, which is like a TRACERT equivalent - it's useful if you have lots of switches but don't know their configuration; for example, if you've just taken over running the LAN.
A wireless-only EtherScope is available, but we looked at the top end of the range ES-PRO. This supports wired and wireless, although unfortunately you can only use one of the two at a time. You can also upgrade a wired-only EtherScope with a Fluke wireless card.
EtherScope is relatively easy to use once you figure out what's where - and especially once you realise that the blue text is the hyperlinks that let you drill through to the next level down. It's not especially intuitive, so if it's a while since you last used it, it will probably take a few minutes to get back in the swing of things, but once you're there, it provides with you a whole stack of information.
Some of this information has explanations available, for example saying why a particular device has been flagged as a security risk, and there is a one-click feature to detect basic problems. For much of it though, you really do need to know what you are looking at.
The device has web and Telnet windows as well as the network analysis application, but its Linux-based Qtopia operating environment doesn't make it all that easy to swap between all these.
Fluke says the Linux base is also one reason why it took so long to bring a wireless EtherScope to market - it needed extra time to develop wireless drivers, not least because the wireless card is a specialist one. For example, a standard card may simply discard errors, but EtherScope wants to keep everything, and it also needs the card to run at the full network data rate. Quite simply, a cheapo card is not an option if you want to do WLAN analysis properly.
The Fluke card can also simulate other wireless cards if you know their RF spec, allowing you to do a site survey from an ordinary user's point of view. EtherScope can be configured for use in different countries too, so it only scans on the locally permitted channels.
This kind of thing is also where Fluke's dedicated hardware and software scores over a WLAN scanner running on a laptop or PDA. Sure, you could do some of the same things with a Pocket PC or similar, but an iPaq's internal bus cannot support the full data rate of 802.11a or g, for example.
For analysis, Fluke bundles a copy of OptiView Console with each EtherScope. This can discover the network, using agents on remote sites if necessary, then store data in an SQL database and do trending on devices and ports, for example.
A very powerful tool for WLAN analysis, the EtherScope WNA is pricey, but if you need this level of detail and information it's a great way to get it.