All main tunnels, bridges, and the interconnecting motorways in the area are monitored and controlled from the new traffic management centre. RWS requested a scalable, future proof solution with crystal clear, real-time images, and very, very high service availability. Optelecom-NKF took up the challenge which resulted in the IP-video network having been operational to their (complete) satisfaction for over a year now.
Optelecom-NKF was asked to design and deploy a multi-service network capable of servicing up to 600 DVD quality video in- and outputs, 144 audio connections, LAN data and all sorts of telemetry. The availability of each service had to be 99,8% or higher. The network should be upgradeable, future proof and, naturally, reasonably priced.
Due to the complexity of the network, the stringent quality and availability requirements, Optelecom-NKF decided to take the complete network design responsibility out of the main contractor's hands. This way, Optelecom-NKF was able to fine tune a Gigabit Ethernet based network to the RWS requirements, and above all, to the enormous load of 600 video streams. The network responsibility covered the design, installation and commissioning of the complete system, from encoders, access-switches, central back-bone routers to virtual matrix software.
The real challenge was to design an Ethernet network which met the redundancy requirements: A cut fibre or node failure in the access ring should have no effect on the other rings and recovery of all services (video, audio and data) should take place within a few seconds.
Optelecom-NKF’s managed Fast Ethernet switches were used in the access rings, enabling the network to switch over in less than a second in case of fibre-breakage. Access rings are separated (segmented by) using Cisco routers as backbone nodes. The backbone of the network was designed to offer a capacity of 14 Gigabit/s, sufficient to support future extensions.
To meet the very high requirements for video quality and low latency, the choice for the video codec was obvious. These MPEG-2 video codecs (C-20) convert video, audio, data and dry contact signals to individual IP streams. External video- and audio matrices are replaced by this virtual matrix function, using Optelecom-NKF's MX™ Control software, which provides a logical interface to process managing software.
In an extensive proof-of-concept testing program, Optelecom-NKF has shown RWS all required functionalities, such as latency, video quality at 8 or 10 Mb/s, compatibility with Barco stream video decoder, and Optelecom-NKF's ability to design GBE networks optimised for IP video.
Managing 600 video streams
All video, audio and data streams are sent to a central router inside the traffic management building. By using multicast for the video streams, video switching and routing is completely executed by the network, using IGMP snooping in the switches and PIM in the routers. The total number of images displayed on 15 personalized video-walls can range from 400 up to 600. This amount of streams has proved to put an extra strain on the local LAN and especially the central router. Careful design was needed to balance the load between the switches in the LAN.
Complete project involvement
During the design phase Optelecom-NKF supplied the main contractor with the basic topology and design of the network. Several training events were organised for both the main contractor and the end user, to explain the theory and offer participants a hands-on experience with Ethernet/IP technology for CCTV applications.
From the concept phase of the project to the writing of the tender documents, RWS always realized the potential risks that were involved in the application of a novel technology. Therefore, they insisted on an extensive testing program, spanning all phases of the project implementation; from proof-of-concept testing at the outset of the project, through various integration tests, to integral on-site tests. Optelecom-NKF played a pro-active role in integration tests with 3rd -party equipment and software to ensure trouble-free interoperability. The Ethernet switches, routers and racks containing the codecs were pre-assembled and preconfigured for efficient installation. Thousands of parameters were configured at the Optelecom-NKF factory by using advanced configuration tools. During the implementation phase, Optelecom-NKF support engineers were on-site, ready to assist in testing and commissioning the system. The traffic management centre (VMC-ZWN) has been fully operational since November 1, 2005.
Author: Peter de Konink, Product Manager Optelecom-NKF B.V.
Please contact Optelecom-NKF about its IP solutions by emailing [email protected]
by telephone: +31 182 592 333 or log on to the website at www.optelecom-nkf.com or www.siqura.com.