ISO 21217:2014 pdf free

ISO 21217:2014 pdf free.Intelligent transport systems – Communications access for land mobiles (CALM) – Architecture
This includes a minimum set of related security procedures and principles that can be verified by an appropriate ITS-related authority described in Reference [54]. These security procedures and principles are used to allow the BSME to assert a level of trust to other BSMEs in the communication network.
The wide variety of services and applications to be deployed in the ITS sector and the global time-varying nature of transportation itself lead to challenges in the design of communication systems to support these services and applications. One of the challenges is to support widely disparate communication requirements with respect to reliability, security, latency, and other performance parameters.Furthermore, the possibility ofhaving multiple applications inan ITSstation unit(ITS-SU) simultaneously competing for communication resources leads to the need for a controlled access to these resources.
Useful means for addressing this issue are e.g. application and message prioritization and logical channels.
ItS communications involves communications between a wide variety of ITS communication nodes on different platforms, e.g. vehicles, roadside equipment, portable devices, control centres, using various means and methods as illustrated in Figure 1. The various access and networking technologies illustrated are used to interconnect stations on a peer-to-peer basis serving a range of ITS service domains. For example, any of the vehicles in Figure 1 connected to an RSE via 5 GHz or IR could communicate with the vehicle connected to the wireless LAN hotspot.
The concept of paths and flows in ITS is very beneficial in describing the abstraction of ITS-S application processes[55] from the communications services available in an ITS-S. This concept is based on similar concepts in IPv6 networking.[103] Procedures for ascertaining available communication paths and for mapping flows to those paths are divided into distinct functions within the ITS-S management as specified in Reference [35].
A communication path is defined as a directed sequence of nodes connected by links, starting at a source node (VCI which connects to the next hop node) and ending at one or more destination nodes.Note that for bidirectional communications, two such paths exist, i.e. one at each peer station. Note further that there could be multiple paths between a source and its destination.ISO 21217 pdf free download.