There is one area of convergence that has a significantly higher need for physical security and IT collaboration than any other: security video system design and deployment. Unsurprisingly, this is the area in which I receive the most questions and comments.
Specifying a megapixel camera where it is not appropriate can needlessly raise the bandwidth requirement of a particular camera. Even “where a camera points” can have an impact on the amount of network bandwidth required. The more continuous the motion is in the camera’s field of view, the lower the rate of data compression will be for the camera’s video stream, and the higher the bandwidth requirement will be. Including a busy street in the fields of view of multiple cameras — where only one or a few cameras will do for appropriate scene coverage — will needlessly raise the size of the camera’s data stream. These factors were simply not an issue with analog camera system design, with each camera having its own cable connection back to the central monitoring point or recorder.
I recently talked to an IT specialist who used the term video network engineering to describe his work. He was completely unaware of the fact that physical aspects of a camera’s field of view environment — and consequently the camera’s placement — could impact its network requirements.
There are many other factors that also impact a camera’s network bandwidth requirement, such as the video frame rate setting (frames per second), which must be based on the role of the camera and what information the security (or quality or training) application needs to have captured.
Most areas of technology convergence require more IT expertise than they do physical security expertise. Video system design and deployment is the significant exception. This is why IT systems integrators tackling video security projects need a video security specialist on board or as a partner (security consultants take note).
Several of this column’s recent questions have elicited a group of responses all centered around network bandwidth and the performance of networked video systems. There are several aspects of these responses worth special attention. Here is a list of comments that typify the responses, with the most frequent comments listed first:
• “IT wants to know what our network requirements are for our security applications. We ask, ‘What kind of requirements, for example?’ And they reply with technical jargon that we don’t understand.”
• “Initially the video system was fine, but now the video display sometimes can’t keep up when we use the PTZ cameras. Once in a while, during investigations, we see the same thing with multiple operators on the video system. We haven’t changed anything about the system.”
• “We want to move to an IP video system, but the IT department is saying that they want the security video system to have its own separate network, not on the corporate network. That would make sharing video for managers and supervisors cost-prohibitive, because we’d have to run the security network through all our facilities. Since recording is a constant number of video streams, but viewing is a variable number of much fewer video streams, we think that we should use a separate network for recording, but use the corporate network for viewing and video sharing. How do we determine the network requirements for each aspect of network use?”
There are many factors that affect network performance for security system network traffic. In order to effectively plan and manage the use of any shared network for security systems (such as corporate network), we must take those factors into account during the video system design and planning stage. They include:
• Security systems traffic — nature and amount
• Other traffic — nature and amount (data systems, VOIP, Internet browsing, etc.)
• WAN maximum and available bandwidth
• Number of individual video streams and maximum bandwidth requirement
• Quality of Service (QOS) requirements for security video
• QOS requirements for all other traffic
• Current and planned future use of the network
Fortunately there is an excellent reference that provides a very thorough education (it gets technical in the middle — but is very well explained with diagrams) on network traffic issues relating to security video system design:
Traffic Engineering for IP Video Surveillance
By Robert Sayle, Cisco Systems Inc.
March 28, 2007
http://www.isc365.com/webinar/Traffic_Engineering.aspx
The presentation includes Cisco’s recommendations for QOS and other performance-related aspects of network design for video. This is an excellent webinar for the IT folks who support your security networks.
New Question
Q: Have you considered a migration strategy to advance to IP video system capabilities? If so, how is that progressing?
If you have experience that relates to this question or other experience you want to share, e-mail me at [email protected] or call 949-831-6788. If you have a question, I’d like to see it. We don’t need to reveal your name or company name in the column. I look forward to hearing from you!
Ray Bernard, PSP, CHS-III is the principal consultant for Ray Bernard Consulting Services (RBCS), a firm that provides security consulting services for public and private facilities. Mr. Bernard has also provided pivotal strategic and technical advice in the security and building automation industries for more than 18 years. He is founder and publisher of The Security Minute 60-second newsletter (www.TheSecurityMinute.com). For more information about Ray Bernard and RBCS go to www.go-rbcs.com or call 949-831-6788.
