ISO 20206:2015 pdf download

ISO 20206:2015 pdf download.Space data and information transfer systems — IP over CCSDS space links
2.4.2 IPE HEADER ENUMERATIONS AND MAPPINGS
There often are many IP data types that require encapsulation. The exact number of protocols depends on the mission and its requirements. These protocols are fully defined in other data standards. Thus the intent here is to identify only auxiliary PDU formats that are often used in support of IP. As a comparison, serial links between routers often carry the 16-bit Point- to-Point Protocol (PPP) protocol field, and the Ethernet PDUs carry a 16-bit Ethernet type field. In these cases, the enumerations of the protocols are defined by the Internet Assigned Numbers Authority (IANA) and the Institute of Electrical and Electronics Engineers (IEEE), respectively. The tables containing the enumerations then point to the standards that define the protocols themselves. The alternative approach would have been to encapsulate a conventional link layer, such as Multiprotocol over Frame Relay, and use its methods for identifying the auxiliary PDU formats. Auxiliary protocols nominally identified at the Data Link Layer in support of IP include IPv4, IPv6, IP compressed header formats, the address resolution protocol for multi-access link layers, link layer control protocols including link metrics exchange and link health monitoring, various Data Link and Network Layer configuration protocols, and authentication protocols.Addressing and routing protocols often tie into these protocols via initial configuration exchanges and link state up/down information. It should be noted, however, that routing protocols such as Open Shortest Path First (OSPF), Protocol-Independent Multicast (PIM), and Border Gateway Protocol (BGP) also maintain their own adjacency or state via hello exchanges or refreshes at the Network Layer. Most of these protocols are built around bidirectional links and require bidirectional exchanges. Since in the space environment it is expected that Network Layer protocols will have to be able to use one-way links, it is not recommended that these protocols be required. It is believed that if fairly simple networks are involved, and they are monitored in a transparent manner, it is possible to use prearranged static settings rather than dynamic exchanges to verify and maintain correct configuration. However, if appropriate for the mission, use of these protocols is not prohibited.
3 SERVICE DEFINITION
3.1 OVERVIEW
This section provides service definition in the form of primitives, which present an abstract model of the logical exchange of data and control information between the service provider and the service user. The definitions of primitives are independent of specific implementation approaches.
When the IPoC service is used for the transfer of IP PDUs, then
– the IPoC service SDU is the IP PDU;
– the IPoC service PDU is the IPE Header + IP PDU.