1 Scope
This Recommendation | International Standard specifies a protocol that is used to
provide the connectionless-mode Network service described in ITU‑T Rec. X.213 ISO/IEC 8348 and to perform certain Network layer management functions. The protocol relies upon
the provision of an underlying connectionless-mode service by real subnetworks and/or
data links. The underlying connectionless-mode service assumed by the protocol may
be obtained either directly, from a connectionless-mode real subnetwork, or indirectly,
through the operation of an appropriate Subnetwork Dependent Convergence Function
(SNDCF) or Protocol (SNDCP) over a connection-mode real subnetwork, as described in
ISO/IEC 8648. This Recommendation | International Standard specifies the operation of the protocol
with respect to a uniform, abstract "underlying subnetwork service". Other Recommendations
| International Standards specify the way in which this "underlying subnetwork service"
is obtained from real subnetworks, such as those which conform to ISO/IEC 8802 or ISO/IEC 8208. The "underlying subnetwork service" may be obtained from real subnetworks other
than those that are specifically covered by the other Recommendations | International
Standards.
This Recommendation | International Standard specifies:
a) procedures for the connectionless transmission of data and control information from
one Network entity to one or more peer Network entities;
b) the encoding of the Protocol Data Units (PD...