Leading suppliers of Internet Protocol (IP) and network-based security products have achieved considerable growth over the last few years on the back of significant IP surveillance-based projects. These have included the Athens Olympics and high-profile installations at Brussels Airport and for the Belgian Railway Network, all of which were designed to deliver functionality and flexibility.
Most security managers recognise that, although their roles have changed significantly over the past five years, with most systems growing beyond all expectations, the fundamental requirements of a security system have remained constant. The evidential quality of the images is paramount, so too easy and swift access to recorded data and the ability to track an individual across a specific area.
These basic requirements haven’t changed at all. At least in part, though, this perhaps explains why IP solutions have not yet been wholly embraced in some key market sectors.
Let’s take the example of a typical Shopping Centre surveillance system and evaluate the requirements against the performance of the technology available.
From a central Control Room the operators can, of course, remotely control and monitor their security and surveillance coverage. Those same operators might easily add access control to the Centre for shoppers and for cars in the underground car parks, along with Public Address and emergency evacuation systems. They could also be looking to link security and surveillance with certain operational functions such as background music (the full range of moods, naturally), customer counting, footfall patterns and even crowd control, plus customer Help Points.
Add to that the Shopping Centre’s building management system (including lift and escalator controls, ambient temperature control systems and fire detection systems). Quite a mix, but…
Single infrastructure management
That’s just for starters! In truth, the integrated system has plenty more features and services for customers and tenants of the Shopping Centre. Video and multimedia channels can provide tailor-made advertising in the Centre according to the store, the time of day and the weather. Short-term promotions or stock clearances can be precisely targeted and effectively advertised. Tenants and customers are provided with access to the Internet and their e-mails through the Centre’s own wireless Internet Service Provider (ISP) platform.
There is, of course, an Intranet for the tenants to share news and information as well as enhancing security measures across the Centre’s outlets, such as tracking suspicious characters from store to store.
Clearly, our Shopping Centre manager now has at his disposal a wide range of essential services and functions that are operated and managed through a single – and, therefore, highly cost-effective – infrastructure. More than that, he’s also making much better use of his security infrastructure through better space planning for car parks, the analysis of customer movements for store tenants and a generally improved Shopping Centre environment. What was formerly a security measure now also becomes a valuable management tool.
Further security enhancements of the system to include behavioural recognition systems enable the intelligent monitoring of busy streets and crowd scenes. Something out of the ordinary – say a litter bin that has been moved – will create an alert. Dangerous overcrowding in a given area could also be dealt with more effectively.
The integration of Automatic Number Plate Recognition (ANPR) systems has become more widespread. Adapting technology similar to that deployed by the Greater London Authority in central London for congestion charging, ANPR systems provide users with the opportunity to manage and control vehicle access to their premises, understand traffic flows, bus lanes and parking, and to assist the police in spotting and tracking suspicious vehicles.
Common transport systems
Transport systems require much more sophistication than just being able to physically ‘carry’ CCTV images, and thus it comes as no great surprise to learn that IP technology is gradually beginning to replace analogue transmission on rail networks and at airports – but have the fundamental requirements of the security system been lost in the process?
New transmission systems require a very large bandwidth to cope with the demands of high quality video images. A 300-camera security system transmitting images in real-time would require, for example, almost 1.5 Gigabits of bandwidth (300 x 5 Mbps), which falls well outside standard Gigabit Ethernet and would necessitate a move to 10-Gigabit Ethernet – resulting in both expensive hardware costs and future maintenance.
To accommodate the restriction in bandwidth and reduce the cost of a 10-Gigabit IP network, high quality images must be further compressed and therefore reduced in image quality, with typical video streams of 1.6 Mbps for most pan, tilt and zoom (PTZ) cameras. A common transport system would also have to provide a guaranteed service for other applications to avoid data collision (figure 1, p45).
IP networks require complex software algorithms to provide a certain Quality of Service associated with traffic classification and priority handling in queues. In comparison, Open Transport Network (OTN) technology – which has been used in many large-scale systems including the Nexus project in Newcastle and for the Docklands Light Railway with much higher bandwidths of 10 Gigabits per second, and the physical separation of each application (figure 2, above left) – would not require additional compression. As a result, any compromising on video quality would not be necessary.
Mission critical applications
It is perfectly understandable that IT managers remain reluctant to share mission critical applications – in other words management tools – on a single network. This helps to explain why some IP-based CCTV systems operate on a private network and don’t share the cost savings associated with a common transport system.
Other areas of concern associated with an enterprise-class security system include the ability to track an individual or a vehicle across a specific area. As such, the CCTV operator’s joystick must be capable of tracking the suspect with minimum delay (latency). Analogue transmission systems provide almost zero latency and, therefore, our surveillance operators have come to expect similar performance from other transportation technologies.
Latency across a digital transmission system is dependent on the latency associated with each component (encoders, switches, decoders and routers, etc). This makes system latency somewhat difficult to quantify. Most operators are willing to accept/compromise if the system latency is below 200 milliseconds. Manufacturers of IP systems, on the other hand, usually provide figures for individual components as system latency which is variable depending on the load of the network. It could be as high as several seconds, which then causes further problems when a common infrastructure is used for multiple applications.
In comparison, OTN uses a fixed time slot for each application. It deploys time division multiplexing. This guarantees system latency – each application boasts a physical separation within a common backbone.
Towards complete integration
One area that is shared between IP and OTN is the ability to stream video images directly to video walls and operator monitors, negating any requirement for the traditional video switching matrix. Most network-based systems provide a ‘virtual matrix’, allowing cameras to be switched to any monitor and enabling full control of all PTZ units.
In addition, camera images may be recorded directly from the network, providing greater flexibility and reliability as well as the ability to expand on a modular basis. The Network Video Recording solution also enables the client to have additional recording systems anywhere on the network (and for disaster recovery in the event of failure at the central site).
Security managers are very sensitive to IP technology. In particular, the basic security requirements of image quality, future maintenance cost and latency must all be considered before they are likely to jump in with both feet.
A common transmission infrastructure can provide real cost savings. System integration has become the norm, but transmission must also provide exceptional reliability if it is to be considered as enterprise-class.
Managing bandwidth demands is an inherent problem with IP-based solutions. As a result, developing the client’s expectations from a sales demonstration room alone is likely to result in an extremely dissatisfied end user.