07/05

Do you know what’s going on in your wireless network? Are all of your access points functioning? Do they all have the correct settings? Are any of the access points or routing gear having trouble due to conflicting channels or too much traffic? Are all the access points at the same firmware revision? Has the RADIUS server service failed? Do you have a rogue access point strategy?

Would you like to know these things before the angry phone calls start for users or customers?

Maybe all you need is to know what’s up or down, or performance versus full-blown configuration and control.

These are important questions for anyone who has implemented or is responsible for a wireless network. This would apply to most wired networks as well. And since a wireless network is just an extension of a wired one, keeping an eye on both at the same time is really easier than it seems.

There are two ways to maintain a network: Management or Monitor.

Traditional Network Management usually means being able to grab performance data and errors from a device as well as remotely configuring the device. These systems can configure access points, switches, etc from a central station. They also can perform functions such as remotely changing server parameters, restarting services, downloading new firmware, etc.

Most Network Management Systems (NMS) use SNMP as the primary protocol. SNMP has been around for many years and is present in virtually all enterprise class products including wireless access points. Most SNMP based NMS systems can support multiple vendors through a file called a MIB (Management Information Base). The MIB contains the message formats needed by the NMS system to talk to a specific vendor’s device. The MIB is loaded into the NMS system and from that point the NMS system knows how to properly communicate with that product.

The problem with most full NMS systems though is the cost. Typical enterprise class NMS systems can cost many thousands of dollars, usually more than many small businesses can afford. Some typical examples are CA Unicenter, Tivoli NetView and HP OpenView.

There are other NMS systems that are specific to wireless LAN’s. These include Wavelink Mobile Manager, AirWave Management Platform, Cisco Wireless LAN Solution Engine (WLSE), Symbol SpectrumSoft WNMS and AdventNet WiFiManager. A few of these packages are vendor specific like WLSE and WNMS. But others are multi-vendor like Mobile Manager and AirWave.

Full wireless NMS’ can all perform rogue AP detection and sometime even rogue AP location and mitigation. Cisco WLSE can detect rogue AP’s and also disable the switch port it’s connected to in some configurations. Mobile Manager and AirWave can detect rogue AP’s but not disable them.

A NMS can require considerable time and effort to get going mainly due to the considerable capabilities.

Now let’s talks about network monitoring.

Network monitoring is really just watching the network. Getting performance data, checking to see if devices are still there, seeing error messages from them when they have trouble. Need to restart an AP or reconfigure it? Sorry, you’ll have to go visit it or use another method such as the device’s built in web interface.

Network monitoring systems can tell you if a Windows Server service failed, or when an AP dropped off the network due to a power failure and came back up. Monitoring systems also use SNMP but just to grab info or send alarms (traps). Many times simple monitoring tools use just a periodic ICMP ping to check if a device is still there. Many simple network monitoring tools can display a map of the network similar to a full NMS.

Examples of Network Monitoring systems are InterMapper and WISPerMapper from Dartware and What’s Up Gold from Ipswitch. WISPerMapper supports a large number of broadband products as well as being capable of keeping an eye on Windows Services such as RADIUS. What’s Up Gold is very capable when it comes to watching fairly large wired networks. These kinds of packages can be considerably less expensive than their counterparts and are generally much easier to get running.