TIA TIA/EIA-732-404

Abstract

<strong>Introduction</strong> <br>This Part defines a protocol fulfilling the role of a Subnetwork Dependent Convergence Protocol (SNDCP) as defined in <em>Internal Organization of the Network Layer</em> [ISO-8648]. <br>Connectionless-mode network protocols are intended to be capable of operating over connectionless-mode services derived from a wide variety of subnetworks and data links. In order to simplify the specification of the protocol, their operation is defined with respect to an abstract <em>underlying service</em>, rather than any particular subnetwork service. This abstract underlying service consists of a single <em>SN-UNITDATA</em> primitive that conveys the source and destination subnetwork point of attachment addresses, a SUBNETWORK QUALITY-OF-SERVICE parameter, and a minimum number of octets of user data. <br>The Subnetwork Dependent Convergence functions providing this underlying service are constrained by the specific characteristics of a particular subnetwork service (<em>e.g</em>., CDPD Mobile Data Link Protocol) and by the assumptions made by the subnetwork-independent protocol providing Connectionless Network Service (<em>e.g</em>., IP or CLNP). Where the services assumed by the Network Layer do not map into the services provided by the Data Link Layer, an SNDCP is operated to provide the required functions.