The IT transformation of the electronic security industry is evident in practically all recently completed and ongoing projects. What started out as a communication protocol to link a few research computers together has resulted in an essentially universally accepted digital communication standard.
The early adopters, the information technology (IT) professionals providing networked business services to their organizations, became the owners of the IT network landscape. Security departments, accustomed to owning and operating dedicated and isolated communications networks, quickly found themselves tenants on the corporate network. This carries a number of clear advantages, not the least of which is the luxury of having, on someone else's payroll, a trained staff dedicated to keeping the network healthy.
At the fundamental level, the goals of the IT and physical security groups are identical. My IT associates have three goals for their networked systems. First, availability: IT professionals pride themselves on maintaining downtime benchmarks that are measured in minutes per year. Second, integrity: The data that leaves the source must arrive at the destination quickly and intact. Third, confidentiality: Transmission paths must be secure from unauthorized access, interception, observation, and interruption.
As security professionals, we would list all of the above attributes as non-negotiable requirements for our system communication networks. Sounds like a great marriage.
Still, the waters often churn when the prospect of a new or expanded network requirement is presented to the IT department by the security group.
IT's big concerns are always associated with the video portions of the proposed system. Network cameras are getting better, less expensive, and therefore more dominant in new and upgrade projects. They also place a big demand on the network's bandwidth and storage.
How Much Bandwidth Do You Have?
Bandwidth is the first discussion point when a new or expanded security system is in view. Security designers must understand the finite nature of the existing IT infrastructure and the need for the IT group to continue to provide existing services to the using community without performance degradation or lapses.
As these designers begin to discuss gross and net bandwidth to determine the impact of the new system, you'll want to understand certain standards of transmission and cable nomenclature. You'll find a short overview in the box below. Another good resource for this information is Bruce Hallberg's Networking, A Beginner's Guide , published by McGraw Hill.
The majority of the installed networks are at the 100Base-T level, while new installations are trending toward the 1000Base-T level. The net or available bandwidth is a multi-variable function of existing traffic, necessary overhead, desired surge capacity, and contingency for growth.
How Big Are Your Images?
The critical parameter the IT staff will need from you is the size of the data stream presented by the security-related cameras and associated devices. Unfortunately, this is an elusive parameter to determine. Table 1 shows some simple calculations based on common assumptions about uncompressed video frame sizes. This provides a good beginning point to determining the bandwidth requirements of the new or upgraded system.
Unfortunately, in practice, determining the size of the video data stream is not quite that simple. A recent publication by Pelco, one of the leading manufacturers of digital video equipment, even says, “For years, the industry was fond of providing concrete numbers for average file size based on image size, resolution and record rate. Unfortunately, there are simply too many variables that affect this actual number.”