Top causes of fluctuating IP cameras
Fluctuating devices are one of the most frustrating issues to troubleshoot on a network.
By Colin Bodbyl
Poorly designed or installed IP surveillance systems can be plagued with issues of fluctuating cameras. Most installers automatically blame bandwidth limitations, but there are several other common reasons for fluctuating IP connections.
Cable runs exceeding 328 feet
The vast majority of IP video surveillance systems rely on Cat5e cable for data transmission. The maximum distance data is rated to travel over Cat5e is 328 feet. Most system designers will measure their cable runs to be within this limit, but a cable run on paper is often very different from how the cables actually need to be run on site. Unforeseen structures, high ceilings, underground conduits, etc., can all add distance to an otherwise short cable run. When cable distances marginally exceed 328 feet, IP cameras won’t stop working altogether, instead they fluctuate and go offline sporadically as data drops out.
Overdrawn POE switches
POE switches vary greatly in price, however lower priced switches come at a cost, usually a smaller POE budget. There are two important numbers to know when calculating the POE budget of a switch. First, how many watts of POE can the switch provide in total. Second, how many watts of POE is each port on the switch capable of providing. Combining the maximum wattage of each port will often exceed the total maximum wattage of the switch, since most switch manufacturers do not expect every port to be used for POE. If IP cameras exceed the maximum POE budget of a switch, they will begin to fluctuate, risking damage to both the switch and the camera.
Bad crimp connectors
The Cat5e used for structured cabling is solid core cable, and should be terminated using connectors designed for solid core cable. Unfortunately, very few installers (and even fewer purchasers) pay attention to what type of cable the connectors are designed for. IT patch panels are almost always designed for use with solid core cable, but surveillance installers tend not to use patch panels and instead go directly to a male connector. Male connectors are usually designed for use with stranded cable which is why this has become such an issue in the surveillance industry. Using connectors designed for stranded cable on solid core cable will work most of the time, however it will also inevitably fail, causing cameras to fluctuate or not work at all.
Often these issues are driven by an attempt to reduce costs. To eliminate the need for additional switches system, designers push cameras to the maximum distances allowed, not accounting for unforeseen changes on-site that might extend cable runs.
In other cases, the cheapest POE switches are purchased by procurement departments that assume all POE switches are the same. When installers use the wrong connectors however, it is usually that they simply do not know better. In any event, these mistakes can lead to countless hours of troubleshooting and unstable surveillance systems that could easily be avoided through proper planning.
Colin Bodbyl is the director of technology for UCIT Online (www.ucitonline.com).