IFSEC saw stands with the latest advance in CCTV technology, promoting Internet Protocol/Networked video solutions.
There are a lot of myths and misconceptions around networked CCTV products and the purpose of this article is to explain it a language we can all understand.
With any new wave of technology, it will be the vendors who truly understand networking and have the clarity of vision to communicate its wealth of benefits that will still be flying the IP flag at IFSEC in years to come.
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TCP/IP
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TCP/IP stands for Transmission Control Protocol/Internet Protocol. It has become an industry standard protocol and, although it was originally designed for wide area networks (WANs), it is now widely used on Local Area Networks (LANs) as well. A WAN simply means two separate networks (LANs) or more connected from different places. For example, this could be a site in Birmingham communicating with a site in London creating a wider means of connectivity and communication. In simpler terms, jump on the M6, shoot down the M1 and you’ve arrived. Motorways connects both cities; this is your highway for transferring data, or in surveillance familiar terms, remote transmission by means of a leased line, dial up PSTN or ISDN line, and of course GSM. (Diagram one) TCP/IP is a very robust protocol and can automatically recover from any communication link failures when used in a pre-configured or internet environment. It re-routes data packets (images) if transmission lines are damaged or if a computer fails to respond, utilising any available network path. Therefore, if the M6/M1 were blocked, the best alternative route would be the M42 and then the M40, effectively a diversion. So, we have a means or highway to deliver information from Birmingham to London; we need a vehicle to travel in. Unlike the flamboyant IT sales reps, we’ll go for the basic vehicle. The vehicle is known as FTP (File Transfer Protocol). Another vehicle on the highway is SMTP (Simple Mail Transfer Protocol). SMTP forms the backbone for most e-mail transfer. This protocol we are more familiar with as this transfers our e-mails globally using TCP/IP. SMTP forms the backbone for most e-mail transfer. FTP is an extremely useful facility, which operates either on the internet or on any TCP/IP network. It provides the ability to transfer electronic files from one host to another in either direction. In CCTV terms it is used to transfer images from the camera or video servers to the desired location. This is your vehicle on the highway. FTP is a stable protocol. It uses the TCP protocol for the reliable transfer of files. The protocol allows the transfer of any file format. But besides a road, and a car, we need a map book to find our destination. An address is required.
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IP ( Internet Protocol) Address
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As it suggests, an address is required for all the devices connected to the LAN or WAN, to ascertain what is being delivered where. Each number must be unique and it’s a global system. If you know the telephone number/IP address, you can route information anywhere instantly on a global scheme. Like our example (diagram two), the address could be areas within London or Birmingham As the picture builds we can now relate to addressing and connectivity of networking in its basic form. Diagram three illustrates the assigning of IP address to the network for peripherals to communicate with each other as and when a request is made to do so.
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Routers and gateways
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A router is used to connect two physically separate networks. The router will forward packets on between these networks. This is because with TCP/IP it is IP which decides the routing to be done. There are a number of IP routers on the market. If we were to compare the network to telecommunications, we can see that making a telephone call behaves in the same manner as peripherals communicating on a network. For example, when a call is made it is routed to a local exchange; it is then routed to your designated location via a series of exchanges. IP connectivity does exactly this but constantly transmits packets of data, literally jumping on the highway and getting of where it needs to. There are many types of routers used to communicate with differing transport mediums.
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For every type of medium, that is, PSTN, ISDN, there is a router available. These routers use dial-up facilities and allow access to a Remote Access Server (RAS). The RAS is generally located on the host site and allows for access to be gained as and when alarms, scheduled events or direct access is required. Many employees are now ‘remote home workers’, which mean they dial up their offices from home to access data and e-mail at their corporate offices. The above transport methods can be deemed as slow and costly in comparison to ADSL. As we know, limitations on bandwidth exist on PSTN and now ISDN based on the demand for higher resolution images and faster streaming of visual media. ADSL being a bigger pipe (up to 512K-5Mbit) can deliver TCP/IP services far more quickly and at lower cost.
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Why is TCP/IP so popular?
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Reasons for the increased popularity of TCP/IP include: TCP/IP is an industry standard protocol; it is a routable protocol suite; and provided on almost all network operating systems, and therefore allows connectivity between dissimilar systems (for instance, from a UNIX computer to a Windows NT computer). It provides connectivity with the internet. The protocols are in the public domain and are freely available, which makes it a popular choice for software companies. There are no restrictions on use, no royalties to pay. It is an open standard where no single vendor has any control over the protocol and anyone is allowed to use it and develop applications based on it. And it is more cost-effective in comparison to traditional remote/surveillance solutions.
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What is a Network Camera?
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A network camera has its own IP address and includes the computing functions to handle network communication protocols such as TCP/IP. This allows it to connect directly to the network via LAN, modem, DSL connection or wireless network adapter. There’s no need for a connection to a PC, so it’s easy to install, and more flexible and cost-effective. A network camera consists of a lens, an optical filter, an image sensor, digitizer and compressor, and software for a web server with network/phone modem interfaces. More advanced network cameras also have such functions as motion detection, alarm inputs/outputs and e-mail support.
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What is a video server?
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A video server includes one or more analog video inputs, image digitizer, image compressor and web server with network/phone modem interface. Video servers digitise analog video sources and distribute digital images over a computer network, turning an analog camera into a network camera. Traditionally, security systems are based on analog CCTV technologies. A video server can connect in parallel with the existing equipment and transmit original video over a computer network.
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System Configurations
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LAN (Local Area Network): 10/100 Mbit Ethernet, such as company intranets, offices, industries, warehouse facilities. Standard modem: offers limited bandwidth, for small businesses, public transportation, home offices. DSL connection: varying transfer speed, for subsidiaries, small businesses, shops, home offices. Wireless network adapter: mobile applications that require live streaming video at for example live events, trade shows, remote locations without internet connection. Cellular phone modem: offers limited bandwidth, suitable for transferring still images from for example construction job sites, remote technical equipment.
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Conclusion
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In conclusion, the arrival of affordable and easy to install network camera and video servers based on ethernet networks set to make remote monitoring more affordable and accessible for any size of organization. But it is also set to change the way in which surveillance impacts on our daily lives. Visit www.axis.com
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Networking is often seen as a complex technical subject. While this can be true, most networks are simple to install and administer.
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Glossary from IndigoVision
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CCTV: Closed Circuit TeleVision – a video system consisting of cameras, displays and recorders that does not allow unauthorized access to any live or pre-recorded video.
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WWW (world wide web): An internet facility that links documents locally and remotely. The web document, or web page, contains text, graphics, animations and videos as well as hypertext links. The links in the page let users jump from page to page (hypertext) whether the pages are stored on the same server or on servers around the world.
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Digital: The representation of a continuous signal with a series of discrete values. The time between each value in the series is constant and known as the ‘sampling frequency’ and the magnitude of each discrete step is known as a ‘bit’; the higher the sampling frequency and the more bits available in the digital domain, the better the digital representation of the original signal. Digital signals have the benefit of being able to be transmitted, duplicated and stored without error.
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Analogue: In the signal processing domain physical metrics, such as movement, temperature, sound and light, are converted into electrical signals with properties that are analogous to the original metric.
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Event management: A feature of some video systems to act on certain triggers, commonly known as ‘alarms’ but may not relate to a security level alarm. Typical actions on a trigger are to start recording video from the camera associated with the trigger, switch on lights, send a quiet signal back to a monitoring station or guard.
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GSM (Global System for Mobile communications): A digital circuit-switched cellular telephony technology that is the predominant system in Europe, but is also used around the world including India and some African countries; it is estimated that there are currently more than 250m GSM users. GSM provides a short messaging service (SMS) that enables text messages of unto 160 characters; it also supports data transfer at 9.6 Kbps to packet networks.
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HTTP (Hyper-Text Transfer Protocol): A communications protocol used to control the connection and transfer of HTML pages between clients and servers – the protocol on which the WWW (world wide web) is built.
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Internet: An IP network that interconnects thousands of other IP networks into a global, publicly accessible digital information exchange.
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Internet protocol: The language that devices and computers use to communicate over the internet; its use has now grown to computer networks in general. Commonly abbreviated to IP.
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ISDN (Integrated Services Digital Network): A standard for providing a digital connection from a customer’s premises to the telephone exchange allowing use of circuit-switched technology.
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Motion detection: A technique for detecting moving objects by analyzing the image content from a video source. Many security industry applications rely on some level of motion detection to help reduce false alarm triggers; accurate and reliable scene analysis will help reduce the rate of false alarms which add appreciable overheads to any monitoring service.
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PSTN: Public Switched Telephone Network. The worldwide voice telephone network. Once only an analog system, the heart of most telephone networks today is all digital.
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Video over IP: Visual communications using the internet protocol as the method of transmission.
