SPECIAL SECTION: Video Networking for Newbies
With the wide availability of high-speed, broadband Internet connections, the network video industry has taken off. Systems that were previously limited in size by the physical limitations of copper and fiber-optic cables can now be world-wide systems viewed, managed and recorded by a virtually unlimited number of locations.
Almost every major (and minor) CCTV camera manufacturer now offers network cameras or network video equipment. The result of this explosion of product is better technology and cheaper prices. It has also helped to increase consumer awareness of network video and increased the pull-through demand on dealers and systems integrators to install these types of systems.
However, this pull-through demand generated by consumer network video awareness has put a strain on security professionals. Many are very proficient in security but are totally lost when it comes to networks. It is like asking a security installer to install plumbing. The installer has had some exposure to the equipment and could probably fumble through the project and even make it work, but the level of competence is not what it would be for a professional plumber.
Not to worry. This article has been designed to serve as an introduction to network video for the security installer. Networks can be very complicated and very confusing, especially for the network novice. As with security systems, there are many ways to accomplish the same thing, and there are many terms used to describe the same device or situation. Let’s delve deeper.
Emergence of Internet, Broadband Spark Dawn of Network Video Era
Before we examine the current state of network video, a review of the evolution of video surveillance in the electronic security industry is in order.
Coax was the workhorse of the CCTV industry for most of the 20th and into the 21st century. RG59, RG6 and RG11 were used to transmit to image management devices, image storage devices and monitor. Large systems requiring long-distance transmission utilized video amplifiers.
When fiber-optic and twisted-pair video transmission systems became widely accepted in the CCTV industry, unamplified video transmission distances increased dramatically. Even with these technologies, a separate cabling infrastructure for the CCTV system was required.
Video transmission over the public telephone network increased the reach of CCTV systems to a worldwide scale. Anywhere a telephone line could be accessed, a camera could be accessed as well. While transmission over telephone lines was relatively economical, it was also very slow. Systems that transmitted real-time or near real-time video over dial-up telephone lines typically did so by sacrificing quality. High-speed data circuits, such as T1, were available but very expensive. Few end users were willing to invest in this technology to remote view their CCTV cameras.
As touched on at the outset, the creation of the World Wide Web and broadband connectivity has revolutionized the playing field and allowed network video to explode. The constraints of the past, in terms of storage, signal transmission and number of viewable locations, have all but been obliterated. Welcome to the age of network video.
Differences Between Network and Conventional Video Explained
Simply stated, network video is video that is transmitted over and stored on a computer network. The network the video travels on can be a local area network (LAN), wide area network (WAN) or the Internet. No matter what type of network the video travels on, the basics of network video remain the same.
Conventional video utilizes cameras with composite video outputs that send video over copper or fiber-optic cabling direct to an image management device. The image management device is often connected to an image storage device where the video is stored and to a monitor where video is viewed.
Network video utilizes cameras or devices with Ethernet outputs that send video over a computer network or the Internet. The video is broadcast on the network, where it can be received by multiple viewing and image management/storage devices. The Internet uses a communications protocol called TCP/IP (transmission control protocol/Internet protocol). This protocol is also used on most modern computer networks. TCP/IP allows multiple devices on a network to communicate with each other and share resources.
The key to TCP/IP is the IP address. Each device on a TCP/IP network is assigned an IP address. The IP address, consisting of four sets of numbers from 0 to 255 separated by periods, identifies the device on the network. This identification allows information to be sent over the network by the device. It also allows information to be received by the device.
A good analogy for an IP address is a telephone number. With a telephone number, a user can make or receive calls.
Network Video Devices Include Cameras, Transmitters, Recorders
Network video devices have an IP address so they can access the network, and they have the ability to send video over the network. The devices may generate their own video via a built-in imager, or they may accept video from other sources and translate it for use on the network.
A network camera, also called an IP camera, is basically a CCTV camera with a built-in Ethernet connection that allows video to be broadcast over a TCP/IP network. A network camera has the built-in hardware and software to transmit video directly over a network.
Network cameras sometimes get confused with Web cameras. Web cameras are less expensive than network cameras, but they require an external PC with an IP address to transmit video. They do not have their own IP address. The external PC requirement of a Web camera makes it undesirable for security use.
A network transmitter, also called a video server, accepts video inputs from external devices and converts them to be broadcast over the network. Network transmitters can accept one or more video inputs at the same time. Depending on the configuration of network transmitter, the cameras may be broadcast as a single IP address (multiple cameras in split screen) or as multiple IP addresses (individual cameras on individual addresses).
A DVR with an Ethernet connection can also broadcast video over a network. The transmission is the same as a network transmitter, and multiple cameras are usually broadcast as a single IP address. The difference is that the DVR typically allows the person viewing the remote video to control the cameras being viewed. The DVR may also allow viewing of recorded video as well as live video.
Many Flexible Options Exist to View Video Via a Network
Network video is typically viewed on a PC or DVR with a network connection. The way the video is received depends on how the network video system is set up to function.
PC viewing of network video can be done with a standard Web browser (e.g. Internet Explorer™) or with specialized software. Using a Web browser requires the user to enter the IP address of the device to be viewed in the address bar of the browser. Instead of typing a Web site name (like www.securitysales.com) the user would type an IP address (like 178.023.145.001).
PC viewing may require specialized software to connect to the remote device. Once the IP address of the remote device is entered into the software, accessing the device is usually a matter of a mouse click or two.
Some devices offer the option of password protecting the viewing of the device. Once the user has accessed the
IP address of the device, an ID and password may be required to connect to the device and view video. The password may limit the user’s access to the device in terms of what he can view.
Some network video devices broadcast video over the network for the sole reception by another device on the network, which gives a video output of the received signal. These devices use the network as a conduit to send video from one location to another. This is useful in applications where cable does not exist or cannot be run between camera and viewing location, or where distance prohibits running a cable.
These devices may also allow viewing by PCs connected to the network as well as the remote receiver.
Network Recorders Can Be Physical Units or PC Software
Network video, like conventional video, usually needs to be stored for future use. The storage requirement considerations for network are very similar to those of DVRs. The actual amount of storage required depends on the file size and how much storage time is required. Fortunately, most network video vendors offer calculators to determine how much storage space would be required based on the system parameters.
Network video recorder (NVRs) are to network video transmitters and cameras what DVRs are to conventional CCTV system. It can receive multiple video signals from multiple cameras over a network connection and record them to a hard drive. The video comes in the NVR’s Ethernet connection to the network or Internet.
NVRs are available as complete units and as software only. When purchasing the software only, the same precautions should be taken when buying video cards and building your own DVR. Be careful of hardware and software conflicts, and make sure the PC used meets the NVR software vendor’s hardware requirements.
Several vendors now offer hybrid DVRs (HVRs). These DVRs are capable of recording video from conventional cameras connected to the DVR and network cameras connected to the network. These systems allow conventional and network cameras to coexist on the same recording device.
Additional Storage Methods Include RAID, JBOD, SAN and NAS
Most NVRs and HVRs support multiple hard drives within the recorder itself, but sometimes the maximum available on board storage is insufficient for the application. NVRs and HVRs will typically support some form of external storage, either attached to the unit itself or to the network.
RAID (redundant array of independent disks) and JBOD (just a bunch of disks) are two forms of external storage that attach directly to the recorder. Both usually use a high-speed interconnection to the recorder, such as SCSI (small computer serial interface), commonly called “skuzzy.” Some units also use connections such as USB (universal serial bus) and FireWire.
RAID is available in different levels, with the higher levels providing more data redundancy. RAID 5, for example, spreads recorded data over multiple disks at the same time. In the event of the failure of a single disk, the lost data can be reconstructed from the data on the remaining disks.
JBOD, on the other hand, does not provide any kind of redundancy. It is as simple as its name describes: just a bunch of disks. The data is stored on the disks just like data is stored in the recorder itself. The disks simply become an extended hard drive for the recorder.
When purchasing a RAID or JBOD for an NVR/HVR, check to make sure it is compatible with the NVR/HVR and that all the required interfaces and cables are included. USB and FireWire cables are fairly common, while SCSI cables as not as common.
Network attached storage (NAS) and storage area network (SAN) are additional options for expanding NVR/HVR storage that attach over the network. NAS is a storage device that attaches directly to the network as another IP address. NAS is relatively basic and simple to install.
SAN is a special purpose, high speed network strictly for storage. It is usually connected to the rest of the network via a high-speed fiber-optic connection. SAN can be expanded to larger sizes than NAS, but is considerably more complicated and harder to manage.
Bandwidth Demand May Call for a Separate, Dedicated Network
Bandwidth is a critical issue for network video products. The amount of bandwidth a device will require will vary depending upon the settings on the device and what the device is viewing. If network devices are to be installed on an existing network, the network manager will want to know what are the bandwidth needs of the equipment.
Network video equipment installed on an office network can slow down the entire network and even cause it to crash. Some product research and discussions with the network manager will save a lot of problems later.
If a network video system will overburden an existing network, the designer or installer may opt to install a parallel network just for video. The entire network (cabling and switch hardware) will be duplicated in places where network video equipment connections are required. The two networks may or may not be interconnected so that the old network can access the new one.
This type of installation may also be done for security purposes, either for protection of the existing network or to protect the security of the new network.
In older networks, signals broadcast by a device are sent to all devices on the network. This broadcast uses bandwidth, even if the signal was not intended for all devices on the network. Some newer network hardware allows signals to be routed based on the device for which they are intended. These newer networks, called switched networks, minimize bandwidth requirements by sending the signals only to the intended devices. Changing to this type of network may require an equipment upgrade.
Network electronic equipment is getting faster and cheaper. If current cabling supports it, the customer may opt to install new equipment to make the existing network faster.
Some cameras have built-in bandwidth controls. Under normal circumstances, the camera may send a smaller amount of data over the network. When the camera detects motion (using built-in motion detection) or receives an external alarm trigger, the amount of data (number of frames of video, quality) may be stepped up.
Time Investment Now Will Mean Monetary Returns Down the Road
Network video is an exciting, evolving technology. The video security factor makes it an attractive market to the traditional CCTV dealer, but the network factor makes many traditional CCTV dealers hesitant to pursue the business. As the network video industry continues to evolve and mature, more and more video will end up being transmitted in this manner.
The best investment a CCTV dealer can make today is to immerse him or herself in the technology and learn to use it effectively. Developing a basic understanding of the features and terminology will help prepare the dealer when the right project presents itself.
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