BS ISO 18440:2016 pdf free
BS ISO 18440:2016 pdf free.Space data and information transfer systems – Space link extension
The Higher Layers represent the functionality specified by the Recommended Standards for SLE transfer services (references [2], [3], [4], [5], and [6]), including in particular:
a) preparation of SLE protocol data units to be sent to the peer application;
b) analysis and processing of the SLE protocol data units received from the peer application;
c) implementation of the state tables defined in the applicable Recommended Standard for the SLE transfer service being provided or used.
The Internet SLE Protocol Layer is further decomposed into the following sub-layers:
a) The Authentication Layer (AL) is responsible for generating and analyzing the;credentials specified in the Recommended Standards for SLE transfer services. For this purpose this Recommended Standard specifies use of the simple authentication scheme defined in reference [11] and the Secure Hash Function (SHA-256) defined in reference [12].
b) The Data Encoding Layer (DEL) is responsible for encoding of SLE protocol data units received from higher layers and decoding of protocol data units received from the peer application. For this purpose, this Recommended Standard specifies use of the ASN.1 syntax defined by reference [9] and of the ASN.I Basic Encoding Rules (BER) defined by reference [10].
c) The Transport Mapping Layer (TML) handles the interface to the Transmission Control Protocol (TCP) specified by reference [7].ISP1 maps one TCP connection to one ISP1 association, which is used by the higher layers for one SLE association as specified by the Recommended Standards for SLE transfer services.
ISP1 provides data encoding and decoding services but does not process SLE protocol data units in any other respect.
For implementations assuming the responder role, the Transport Mapping Layer provides a service to listen for incoming TCP connection requests. It therefore provides an interface by which higher layers can request to start and stop listening for a specified SLE responder port identifier, which the TML maps to an IP address and a TCP port number.
Except for the interface to control listening, all interfaces refer to one association only. ISP1 association establishment and release involves only the Transport Mapping Layer. Once the association has been established, all SLE protocol data units are passed through the Data Encoding Layer and the Authentication Layer.BS ISO 18440 pdf download.
