Bandwidth Battle

As surveillance solutions ride on the network, systems integrators need to make sure their consumption is realistic and planned

Current bandwidth on Local Area Networks (LANs) and many Wide Area Networks (WANs) is much more robust and capable of handling increased network video traffic. And many options in storage such as a Storage Area Networks (SAN), a separate network used for data traffic that cuts down on the bandwidth consumption of the IT network, have helped. And the choice between wireless and hardwired networks and the bandwidth and security that each offer is yet another factor that applies to the 'bandwidth battle.'

Yet as developments in IP and HD video and the move to integrated video surveillance coupled with access control continue, the need for more bandwidth and higher download speeds is inevitable. The concern is that most of this increased capacity was put in by the IT department for other applications and the onus of fitting into this world is dependent on the security professional. As an industry, it is up to us to make sure that what we are installing in video systems serves not only the needs of security, and thereby the enterprise, but meets the daily network needs of other applications.

Bandwidth specifications

There are several factors that affect storage-whether the camera is analog or IP, size of the megapixel camera, whether the compression format is CODEC, MJPEG, H.264, what frame rate is necessary to record at and others. In turn, all these factors have to be taken into consideration as far as where the camera is being placed, overall viewing distance and what other systems/functions it is being used for and with.

If a network has been designed to run at 1000Mb/s, or Gigabit speed that doesn't mean that it will run at that speed all the time. That is a bandwidth specification based on burst traffic like most client/server applications. In the video world, once we have used up 60 percent of that capacity, we are starting to push equipment beyond the design specs and also will leave no room for any other applications on the network to function effectively. As soon as the video starts taking over that much of a network, the IT staff will isolate the offending devices and deny their use.

Using network bandwidth requires a great deal of finesse in getting the numbers right before the first piece of equipment is purchased. There are numerous bandwidth/storage calculators available from most major manufacturers of video equipment, which can aid in determining the needs of most installations (see page 36). These tools can help determine which cameras need more bandwidth based upon location, movement or any other factors, and helps to ascertain the overall usage. Once an aggregate has been made of what the maximum usage might be, the decision whether to run on the customer's network or build a separate network for video will become clear. The key is to make sure that network design for the separate network fits in with the customer's IT department standards. If the IT department uses all Cisco gear, then don't bother proposing HP, or worse yet, something inferior and cheap that surely won't get the job done. The IT department's concern is that once the integrator is done with the installation, then their department will be stuck maintaining and monitoring all of the new equipment. Make sure that IT is aware of all technical aspects of the specification that may involve them or affect bandwidth consumption and get their approval beforehand.

Looking beyond H.264 compression

Technology has evolved to make the bandwidth and storage scenarios clearer with advancements such as H.264 (also known as MPEG-4 AVC) which is far superior to the widely used MPEG-4 and MJPEG technologies. In fact, H.264 has become a defacto standard for compression and will most likely remain so for many years. The difference in storage and bandwidth using H.264 technology makes it a no brainer. Bandwidth and storage can be cut by at least one third with higher quality images. The sacrifice of quality for bandwidth does not have to be as severe as it once was and playback video is far superior to most analog systems available.

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