LAN cabling’s new role
IP-based video-surveillance systems are pushing their way into data networks.
Written by Carol Oliver, Marketing Analyst, Berk-Tek, a Nexans Company
Reprinted from Communications News, January 2007
IT managers are discovering that their voice and data network systems are being expanded for converged applications over the same physical cabling infrastructure. Standalone systems, such as CCTV, access control, security/intrusion, audio/visual notification and building automation systems (BAS), are moving from non-standard isolated systems to an integrated system over the installed network through IP-based functions. In fact, IP-based video surveillance is expected to represent 50% of the video-surveillance market by 2008 (source: Lehman Brothers).
Through IP, the migration of analog, digital and network security devices into the upper layers of the open systems interconnection (OSI) model are creating new dynamics for the cabling infrastructure. The use of open standards allows compliant infrastructures to remain in place while other modules or components are added. Open standards encourage this modular approach to systems design, whereby components from several manufacturers can be incorporated into a common infrastructure with common protocols.
By utilizing an IP-addressable system, remote computer monitoring and communication of converged applications bring centralized control of these applications to IT and facility managers. When selecting a structured-cabling system, the IT manager is now responsible for looking at the long-term return on investment, as the installed network today must be able to handle the speed, bandwidth and power requirements of these emerging applications.
There are existing standards for structured cabling that can be applied to security applications over an IP-based system. Proven interoperability principles and standards have been formulated in IEEE 802.3 IP protocols and ANSI/TIA/EIA standards governing cabling, connectivity and pathways. These standards allow video applications to integrate onto one common cabling platform.
This interoperability includes common media, connectors and topology with the voice, data and facilities networks. This saves time and cost in material selection and installation labor, while also making the network system easily scalable, without having to recable.
An integrated digital security system over the network allows a more proactive approach to surveillance and data mining. For many years, video surveillance was accomplished by attaching an analog (CCTV) camera with coax cable to a dedicated monitor and a VCR for recording. This system relied on human observers, normally watching multiple screens and hours of videotape in a control center to trigger any type of response. These early video camera surveillance systems were installed by security camera contractors who did not have the knowledge of the structured cabling systems, as the LAN systems were kept separate and managed by the IT department.
Today’s analog and digital IP cameras can be connected through structured cabling and attached to digital network storage devices. The data produced can be used for analysis through the LAN and WAN, in addition to video mining. It can also integrate with other applications, such as access control, utilizing multifactor authentication, including biometrics and BAS over the same network through the same cabling infrastructure.
Through structured cabling, today’s security systems can incorporate both analog and digital cameras, which are connected via unshielded twisted-pair (UTP) cabling to digital video recorders (DVRs) or network video recorders (NVRs) in the telecom room or data center. Multiple functions, such as power, video and data, can be delivered simultaneously on one UTP four-pair cable.
“The path to IP does not necessarily mean replacing analog cameras with IP cameras,” states Mike Mahan, vice president of sales for NVT, a manufacturer of video transceivers and hub systems for CCTV. “IP-based video is accomplished by two methods: digitization/encoding of video by a discrete device from an analog device (camera), or deploying IP-based cameras. Since 85% of CCTV installations still support analog cameras, the convergence to IP-based video utilizes hybrid alternatives, which is a mix of analog and IP over a UTP-based structured cabling system.”
Because analog cameras utilize coax cable connections, UTP CCTV transceivers are connected to the camera’s video output and the horizontal cabling, which convert an unbalanced 75-ohm signal to a balanced UTP 100-ohm signal. The first of two hybrid alternatives incorporates an analog camera, which is connected to the DVR in the control center where the video is stored and reviewed by security personnel. Through the network, the DVR is connected to an IP output.
The second hybrid alternative connects the video signal from the camera cabled directly into an encoder, which is connected to anNVR via the IP network. An NVR acts like a server with direct network video connection, and utilizes storage capacity through the network. In contrast, the DVR has a separate hard drive for storage and connects to cameras using traditional analog signals.
All connections from cameras to the DVR or NVR utilize the structured cabling infrastructure through patch panels in the telecom room. Connecting the DVR and NVR directly to the network allows users on the network to access the video output through the same cabling infrastructure.
“The benefit of the hybrid models is that you can still take advantage of legacy analog camera technology, which offers a clearer picture and does not require any network bandwidth, as analog transmission only utilizes Layer 1 of the OSI model until it is converted to digital by the DVR or encoder,” explains Mahan.
“The next logical progression is to carry the digital signals over a structured cabling system through IP or network cameras,” states Paul Koebbe, national market manager, security, for Graybar Electric Co. “IP-addressable cameras can be placed anywhere on the infrastructure, as electronics that are handling other IP traffic can easily be integrated with the security system.”
Network cameras contain the optic, imaging system and encoder to capture and transmit live images via an Ethernet port over an IP network, such as LAN, intranet or Internet. This enables users to remotely view and/or manage the camera from a Web browser on any computer, including pocket PCs and PDAs, from anywhere, at any time.
A major concern in selecting an efficient structured-cabling solution is to ensure that the system will be scalable to handle the additional bandwidth and electrical requirements of these converged applications. Once IP cameras replace existing analog cameras, the UTP-based cabling will need to provide highbandwidth IP data, as well as sufficient power and control for applications such as pan-tilt-zoom (PTZ). In addition, the structured-cabling solution should be upgradeable to integrate with future applications, such as access control and other BAS functions.
Fiber is the preferred media for backbone connectivity between closets and for long-distance horizontal cabling for cameras located more than 290 feet from the patching fields, such as out to guard shacks. Horizontal distribution of data, video signal and power to cameras within the 290-foot limit via the network can be accomplished with Category 5e for today’s applications. Network integrators and IT managers, however, need to be aware of the bandwidth required in the future for high-resolution megapixel images and disk space for storage, as well as the added heat generated when using the same cable for power over Ethernet (PoE) over UTP.
Currently, IEEE 802.3af specifies Ethernet-delivered power at 12.95 watts. Evolving applications will require greater power to run PTZ cameras at up to 30 watts and access control systems up to 25 watts. The next-generation standard, IEEE 802.3at, or PoE Plus, is being designed to operate over Category 5e or Category 6, and will increase the powered device load to a minimum of 30 watts.
Installing a higher grade of cable, such as enhanced Category 6, will provide more headroom for extended bandwidth capabilities, lower insertion loss for stronger signals, improved crosstalk immunity for better picture quality, and improved resistance to higher temperatures for PoE. Through an Ethernet/IP platform, the convergence of multiple systems over a reliable UTP-based cabling solution will mean lower construction costs, lower cost per port, reduced maintenance costs and centralized management.