VIS-CAM System
11 Appendix G: Ethernet Requirements.
The Ethernet media is the key component for data transmission in the
In order to ensure a smooth running system, install the Ethernet infrastructure with the following considerations in mind:
•Physical cabling - minimum Cat 5E is recommended – in larger systems, Cat 6 or fiber optic cables are recommended for backbones with high traffic loads. It is strongly recommended, that the quality of the installed Ethernet cabling is verified with a suitable network tester (certifier) such as Fluke Optiview, Fluke Etherscope, Lantek 6 or similar.
•Network speed – The minimum speed required is 100 Mbit – though 1000 Mbit (1Gbit) is the optimal speed and ensures sufficient bandwidth in most applications. In general, assessment of network speed is an important issue, and should have been taken into consideration in the design phase. The transmission speed on a local gantry with (for example) 4
Figure 96. Network cabling example:
•The actual traffic load that the individual cameras inflict on the network depends heavily on the cameras current run mode – in a normal operable system, the cameras run in asynchronous mode, which means that the cameras only grab images when triggered. Converted to network load, asynchronous image triggering with a rate of 3600 incidents per hour (a car per second) will typically inflict a
Throughput per lane: Four (4) vehicles per second for a five (5) second burst rate – not indefinitely sustainable. One vehicle per second sustainable indefinitely.
Appendix G: Ethernet Requirements | 95 |
