scope:

This Technical Specification specifies the general rules for anon-board data communication system between the different systemsthat may be used within public transport vehicles. This includesoperational support systems, passenger information systems, farecollection systems, etc. This Technical Specification describes: ?the requirements for an on board IP network; ? the overviewarchitecture and components for an IP based on-board network; ? themodular structure of the network architecture; ? the ServiceOriented Architecture (SOA) approach, and approach to definingservices. Systems directly related to the safe operation of thevehicle (including propulsion management, brake systems, dooropening systems) are excluded from the scope of this TechnicalSpecification and are dealt with in other standardization bodies.However, the architecture described in this Technical Specificationmay be used for support services such as safety informationmessages. Interfaces to safety-critical systems should be providedthrough dedicated gateways with appropriate security provisions;for the purposes of this Technical Specification, these areregarded as simply external information sources. This TechnicalSpecification is designed primarily for vehicles with a fixedprimary structure, where networks can be installed on a permanentbasis and the system configuration task consists largely of theintegration, adjustment or removal of the functional end systemsthat produce and/or consume data. Public transport vehiclesconsisting of units linked temporarily for operational purposes(specifically, trains in which individual engines, cars or consistsare routinely connected and disconnected) require additionalmechanisms to enable the communications network itself toreconfigure. Such mechanisms are provided through other standards,notably the IEC 61375 series. (See also 5.9.)