Design Issues for running your CCTV System over your LAN
Manny Romero, Director of PAQWORKS Data Communications, provides an overview of the critical issues concerning networking in security applications.
Integrating Security Applications via Ethernet
Traditionally CCTV, Alarm Systems, Access Control, Intercoms and the like are more often than not supplied and installed by different vendors. And, even if they are all from same supplier, they often still require a separate network infrastructure for each system: CCTV over Coax; Access Control using RS485; Alarms over PSTN/GPRS; and Intercoms over twisted pairs.
It may still be a while before we see tightly integrated applications at the software or “Dashboard” level, but it’s a different story when it comes to connectivity. Convergence is here already in the form of a common data transport infrastructure – Ethernet.
The move to Ethernet means that security products that previously ran on their own proprietary network can now share the same physical layer.
There is no doubt that putting all you eggs in the one basket by using Ethernet to transport all security services requires careful attention in the design of the network, choice of hardware and integration.
This article provides a brief, practical guide to some of the issues that need to be considered when designing a security system LAN.
Making the Switch to IP for CCTV
CCTV has been the first of the security family to make the switch to Ethernet or IP (Internet Protocol), and some early adopters have had their fingers burnt as cameras can be the most challenging from a networking design perspective.
Despite this, the move to IP Cameras is rapidly gaining momentum.
The latest generation of intelligent IP camera and network technologies enhance performance and reliability well beyond that of traditional CCTV systems.
The basic principles of network design highlighted apply to any combination of networked security devices.
Use Industrial-Rated Components
Over the past five years, the automation and controls industry has successfully migrated to Ethernet-based networks, in the most demanding and critical of applications such as mining, oil and gas, utilities and manufacturing.
A key component of any Ethernet network or LAN is the Ethernet Switch. It’s what links together the various segments – Cameras, PC’s, Servers and Storage.
If it fails, all devices connected to it can no longer communicate with each other.
Most Ethernet Switches employed in the commercial environment are designed to sit in air-conditioned rooms.
However, deploying IP cameras across a reasonable-sized area, like a campus or an airport, requires the installation of Ethernet switches mounted within 100m from the IP camera, (100m being the maximum distance a copper LAN segment can extend).
This means switches may need to meet relatively harsh environmental conditions.
Industrial Grade Ethernet Switches provide many benefits in this regard:
- No fans for maximum reliability, with no moving parts to fail
- Wide operating temperature range allows their use anywhere
- High immunity to EMI/RFI
- Built in Fibre Optic ports allows for long distance connections between switches
- Integral diagnostics provide alerts to operators of any problem.
Use Redundant or “Self Healing” Network Topologies
Topology refers to the physical layout or shape of a network. Imagine a network with four locations, with each location having up to six cameras all needing to access a central server for recording. The most reliable solution would be to link all of the four Ethernet Switches together in a ring. This is called a Ring Topology.
The advantage of a Ring Topology is that a break between any two switches would still allow communications between all devices.
This concept is referred to as Media Redundancy, due to the fact that there is an alternative media path.
The media for large sites would be Fibre Optic, which allows distances of up to 100km between each Ethernet Switch, or CAT5 for distances up to 100m.
Another feature of Industrial Ethernet Switches is that any break in the network is instantly reported via email or relay output, ensuring speedy repair
Simplify Installation & Reduce Costs With PoE
PoE or “Power over Ethernet” is a recent development that will have a huge impact on networked security applications.
PoE refers to the ability to have the RJ45 port of an Ethernet Switch supply both Power to the connected device, and communications. Most quality IP cameras and switches now support PoE, as do increasing numbers of other security devices like Intercoms and Access Control Systems.
Use of PoE eliminates the need for local power at the camera location, significantly reducing installation costs.
A secondary benefit is the ability to easily provide UPS or back up power to all cameras at minimal cost via the PoE-enabled Ethernet Switch.
All PoE-enabled devices connected to the switch are also backed up and protected against any power failures and glitches, with no additional wiring or cost.
Use an Industrial Firewall for Network Security
Firewalls act as barriers, separating one network from another. It is vital that connection between a security LAN and the corporate LAN, WAN, and certainly the Internet, be very tightly controlled.
Industrial Firewalls are specifically designed to be used in remote locations without air-conditioning, are more user friendly than those used by IT departments, and are able to physically isolate or disconnect a security LAN from any other network.
Firewalls also provide diagnostic information on network performance, alerting users to any attempted attacks or overloads.
Use GigaBit Ethernet for Bandwidth to Burn
Since Ethernet was first introduced, data transfer speeds have increased rapidly from 10Mbs to 100Mbs to Gigabit (1000Mb), with 10 Gigabit now starting to become available.
Bandwidth is no longer a barrier when it comes to the use of IP and switched networks.
Use Fibre Optic
Fibre optic cables and associated hardware is now much more affordable. Fibre ensures no eavesdropping, immunity to interference and the ability to span longer distances.
The latest generation of Ethernet Switches provides the option of using just one Fibre core. This can allow IP Networks to run over the same single Fibre that had previously been used for transmitting video.
Use Distributed Storage
Storage for CCTV has always been a major cost, however, the latest IP cameras can record directly to any standard commercial file server (Linux, Windows) or NAS Device (Network Attached Storage).
With NAS prices tumbling, higher quality images can be stored for longer periods to very high degrees of security against loss of data, basically taking advantage of what IT people have been perfecting for over a decade.
Users are no longer tied to a particular vendor of DVR or NVR hardware. They can choose from a plethora of hardware suppliers. Redundancy schemes and storage capacity can be tailored to any budget and scaled as needed.
And, unlike CCTV, where all cameras often connect to the one “central” NVR, there is no single point of failure.
Take Advantage of Converged Solutions
IP devices have high degrees of intelligence. An IP Network Camera, for example, can do much more than just send video to a remote location.
Often users perceive the difference between IP Network Cameras and traditional CCTV as just the communications method. But the difference in functionality is much greater than this.
Digital technology allows users to have one device perform multiple functions. Or incorporate features that previously required multiple devices.
For example, the latest generation of IP Network Cameras from German industry leader MOBOTIX include a wide range of functions to take security surveillance to a new level.
The Virtual Security Guard
These cameras are an inexpensive alternative to a security service. They can be installed at all “critical” locations, operated around the clock, and configured to trigger an event-based alarm.
In such an application, a single gatekeeper would have a clear view of all “critical” locations like building entrances, and could utilise the IP Network Camera’s integrated intercom to talk to visitors, or to open gates/barriers.
In remote applications, IP Network Cameras can be set up to automatically issue an alarm or play a warning message when an ‘event’ takes place. For instance, if a person is detected in a secure area, the IP Network camera can warn the intruder that their presence has been detected and they are being recorded, making the camera a ‘Virtual Security Guard’.
Taking a pre-emptive approach to security in this manner can translate to significant reduction in vandalism for example.
Future Trends
The trend is clear: IP Networking for security applications is here. More and more security products are becoming available with network connectivity.
Truly “Integrated Security,” defined as one software platform or at the very least interoperability of software across all vendors is what users want.
The Industrial controls world is well underway with standards like OPC that provide such capability, based on Ethernet.
The security industry should take note - customers want convergence and interoperability. If the security industry does not listen, IT, BAS (Building Automation Systems) or control systems suppliers will.
Take a look at what industry giants like GE and Siemens are doing in this area for a glimpse of what’s in store!
Further information: PAQWORKS, Unit 3, 41 Higginbotham Rd, Gladesville, NSW 2111. Tel: 1800 727 979. Fax: +61 2 9877 6277. Email:
manny@paqworks.com
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