The local multimedia network of THALASSA
Data communciations aboard a research vessel are of the utmost importance. Data-processing cannot be implemented without a highly efficient, open and well-developed network.
This communication network must not only offer the scientific community the full services available in any company network, but it must also carry data collected by the ascoustic sensors located in the ship's hull and video images from the surveillance cameras.
Aboard the THALASSA, there are numerous video sources which are easily integrated into the computer network.
The concept of a digital network supporting computer data and the numerous video images created by the on-board cameras allows :
- broadcasting of large amounts of graphical data,
- simultaneous display of multi-windows on an X terminal :
- images created by the cameras,
- animated graphics for ship navigation and the expedition,
- digital data.
Real time sub network for navigation,
Real time network for data acquisition systems,
Real time network for video and graphic broadcasting,
E-mail and data transmission to laboratories on land.
Quick network overview :
( For more details, click on the system name)
Main network specifications :
Network head :
THALASSA's local area multimedia network comprises the network head, or head-end, located in the computing centre and the cabling to all stations.
The architecture contains :
- a real-time Ethernet segment for navigation,
- a real-time Ethernet segment for acquisition systems,
- a real-time Ethernet segment for video equipment,
- an Ethernet segment for data transmission ,
- ports for the external network (VICTOR 6000, SAR,etc.),
- a switch/router for the connection of all segments,
- a router for acces to land-based networks via INMARSAT-B,
- adminstration by software.
The physical medium features :
- stern to stern category 5 certification,
- twisted pair medium, 12 km in length,
- 208 points of connection,
- RJ45 standard sockets,
- star-shaped structure,
- bracing system "managable",
- administration by software.
Real time subnetwork for navigation :
This was defined to provide the ship with maximum safety. It is essentially supports TS-CINNA central navigation composed of 3 sub-systems under Ethernet.
Under this subsystem, only the system's environmental data and external datagrams authorized by the filtering section are circulated. With this method, any distrubance will not affect the other subnetworks, and in particular, the equipment dedicated to poastprocessing.
Real time network for data acquisition systems :
This section of Ethernet supports :
- all the scientific acquistions and ship-related techniques, in particular :
- the fish sounders MICREL and SIMRAD with the software manager associated with TS-MOVIES,
- the TS-CITE and TS-TERMES technical and scientific stations,
- specialized aquisition systems (ADCP current meters, SEABIRD bathysounder, etc. ),
- the TS-ARCHIV centralized archives of the data,
- the TS-VIDOP display system,
- TS-CASINO automated watch.
All these systems generate considerable traffic on this network. Just as in the navigation subnetwork, a filtering process has been defined to authorize only essential datagrams from outside the system.
The real time network for video and graphic broadcasting :
ATM technology was used for this sub network to comply with the constraints of broadcasting digital data on a computer network.
This segment of ATM consists of :
- an ATM switch of 155 Mbits / second with 8 ports to allow the digital video in MPEG format,
- an ATM / Ethernet switch of 24 ports distributes in TCP / IP multicast mode digitized videos to every scientific work station on board .
It also includes the following equipment :
- 1 server with video cameras. These use the input from sensors to generate animated graphics which are distributed to the ship computers,
- 20 multi-window screens, these are distributed over the ships' network.
All the equipment required for post-processing is connected to the navigation crew PCs (service points, machines and electronics).and electronics
These principally include :
- THALASSA's server,
- work stations and PCs for post-processing,
- office PCs,
- printers and plotters,
- crews' PCs.
Specialized equipment for surveys, if any, can also be connected to this network.
E-mail and data transmission with laboratories on land :
Scientists and crew on board can use the system of electronic mail via the INMARSAT-B satellite. The equipment used is the same as that available in a land based laboratory.
The following are available :
Supervision tools are available for electronic mail management.
This system was developed by B2I.