AB Inter NET Work : 4 areas of expertise
The field of transportation is specific because it combines highly different but essential services: Traffic Monitoring System (TMS), Detection Support System (DSS), Automa- ted Traffic Detection (ATD), Emergency Call Network (ECN), road equipment management, road traffic management, Automatic Incident Detection (AID), Centralized Technical Management (CTM), CCTV, data collection, ticketing management, Changeable-Message Sign, fire detection, interphony, ventilation, signalling, telephony,… Whether for a highway, a tramway, a tunnel, an airport, or a port, redundant multiservice networks make the operator’s work easier and more efficient.
It is crucial that such networks rely on a proven, reliable, and efficient infrastructure.
Whether on the same Ethernet network or on distinct networks, where Layer 2 & 3 are judiciously mixed, equipment choice and configuration are sensitive steps, because they ensure user’s security, adapted performance, operational efficiency 24/7, and easy maintainability.
During site architecture design, site commissionning, site acceptance and site operation, it is crucial to select a network partner who masters these elements in order to stay confident in the full success of the project and in the respect of deadlines.
CCTV involves multicast flow management over the whole network and has a massive impact on the network load. It usually requires all the flows to be concentrated on the backbone and on some specific location (video wall, archival program, display stations…). A sustainable architecture must be adapted and forward-looking.
The main goal is, not only, a question of implementing an architecture where the only configuration to settle is an efficient redundancy solution. Architectures require the network core to be suitably dimensioned with the set-up of VLANs, redundancies, access security, multicast flow management, routing, and Access List (ACL), service quality, multicast/broadcast filtering…
Once again, the selection of mechanisms must be adapted to sites, to needs, and to maintenance teams.
Automatism has long used Ethernet networks in the field of Centralized Technical Management and process monitoring. However, sensors/actuators, traditionally connected via an automatism manufacturer’s proprietary bus, are more and more evolving towards Ethernet. Known fieldbuses, such as Modbus, Profibus… are migra- ting toward Ethernet to become Modbus-TCP, Profinet, Ethernet/IP, …
These protocols migrate from a proprietary bus to a single support with, in some cases, proprietary versions that derive from standard Ethernet.
The new automatism protocols for Ethernet in critical real-time industry applications not only require knowing the solution implications but often also involve a change in communication modes.
The Client/Server mode is moving toward a Publisher/Subscriber mode. This change implies an extensive use of multicasts and therefore requires the network equipment to be specifically set-up, in both switched and routed architectures, to avoid forwarding data to all the devices.
These new architectures require the implementation of redundancies, most of the time VLAN, multicast flow filtering, management and routing… Behind the scenes, these mechanisms must also be adapted to the site, needs, and also to the maintenance team’s know- ledge.
In IEC 61850 electrical substations environments, more than on process and transportation, it is necessary to ensure a seamless availability of the Ethernet network. So far, the fastest redundancies were used as the Hirschmann HiPER-ring with a typical healing time of 40 to 50ms.
Now, for this mission critical industrial application, with the help of the newest redundancy protocols, like PRP and HSR (both IEC 62439-3 standardized) that the most recent Hirschmann products implements, there is no more healing time and the network is able to handle a failure of the fiber without loss of a single packet. For this kind of project, there is also the need of a clock precision brought by the IEEE-1588 protocol.
Of course, to control this feature, a simple ping test is not enough and other software tools are simply not powerful enough to certify a successful implementation of this technology and thus confirm that there is no healing time. Even using a traffic generator able to provide 150,000 frames / sec (on a 100Mbit/s network like the one used by PRP or HSR), which requires a PC able to absorb 1.5 million frames during a 10 sec. breaking test (to measure the loss during a break). Moreover, it is necessary to measure the redundancy for different frame sizes (from 64bytes to 1518bytes), those with 64 bytes being more demanding on resources within the network equipment.
Within AB inter NET work, we already made tests in this environment and we are able to test and certify your solution by using two dedicated tests devices used to load the network up to 100% (in 100Mbit/s or 1Gbit/s) and controling the effective loss rate during downtime (this test is part of the RFC 2544’s network certification).
We can assist you in setting up your infrastructure on: its design, implementation, validation and training of your field maintenance staff.
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