With voice and video capabilities now integrated into virtually all LAN hardware as standard, more firms are starting to investigate how best to take advantage of the technology.

Moving the internal phone system to the data network is one obvious option, although it is not one that many firms feel confident enough to pursue. Another, less ambitious application for the LAN is to host a surveillance system.

A growing number of IP or network cameras are available, with prices falling as more mainstream IT vendors such as D-Link join specialists such as Axis in the market. Devices are available for connection to wired or wireless LANs, allowing flexibility in siting and installation.

These devices offer colour image resolutions up to 640x480 pixels, usually much higher than traditional closed circuit television (CCTV) cameras, which rarely deliver more than grainy black and white images at best.

Cost savings are difficult to quantify, though, given that most companies would have to shell out for new hardware and software while keeping their CCTV network running as a backup or scrapping it completely. Also, network managers need to keep in mind that the higher the camera's resolution, the more LAN bandwidth it will usually consume.

And while an IP surveillance system can centralise video security management in the network, that might be a mixed blessing depending on how complex the LAN becomes, and how many people are employed to look after it.

Not that any existing head of security systems must necessarily be handed his or her P45. Rather, they can simply install a management interface from which to administer the video security network from a single PC displaying multiple windows; rather than the bank of monochrome monitors that historically defines CCTV equivalents.

Security experts say that images caught on IP cameras, unlike those recorded onto video cassette, can be emailed to the police much more quickly or even viewed live over the internet during an incident to help the local constable gauge the nature and seriousness of the threat.

Giving the camera an IP address also means that cameras can be accessed via the internet, which can be helpful to network managers who need to keep an eye on remote sites as well as the building in which they are located.

However, it is a good idea to protect those links with virtual private network technology, otherwise burglars could check camera views over the internet, to identify weak points for entry, work out floor plans, and identify periods when few people are around.

Another downside is that if the network goes down, so does the video security system, along with the telephone system in some cases, though this is a problem that can be surmounted using the usual methods for network resilience.

All of which means that companies must consider their options very carefully, and preferably conduct a pilot test, before investing in video IP surveillance systems.

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