RFC 2043 (rfc2043) - Page 3 of 7
The PPP SNA Control Protocol (SNACP)
Alternative Format: Original Text Document
RFC 2043 PPP SNACP October 1996
1.2. Terminology
This document frequently uses the following terms:
datagram The unit of transmission in the network layer (such as IP).
A datagram may be encapsulated in one or more packets
passed to the data link layer.
frame The unit of transmission at the data link layer. A frame
may include a header and/or a trailer, along with some
number of units of data.
packet The basic unit of encapsulation, which is passed across the
interface between the network layer and the data link
layer. A packet is usually mapped to a frame; the
exceptions are when data link layer fragmentation is being
performed, or when multiple packets are incorporated into a
single frame.
peer The other end of the point-to-point link.
silently discard
This means the implementation discards the packet without
further processing. The implementation SHOULD provide the
capability of logging the error, including the contents of
the silently discarded packet, and SHOULD record the event
in a statistics counter.
PIU Path information unit. A message unit consisting of a
transmission header (TH) alone, or a TH followed by a basic
information unit (BIU) or a BIU segment. PIU is analogous
to datagram.
TH Transmission header. Control information, optionally
followed by a basic information unit (BIU) or a BIU
segment, that is created and used by path control to route
message units and to control their flow within the network.
BIU Basic information unit. In SNA, the unit of data and
control information passed between half-sessions. It
consists of a request/response header (RH) followed by a
request/response unit (RU).
message unit
In SNA, the unit of data processed by any layer; for
example, a basic information unit (BIU), a path information
unit (PIU), or a request/response unit (RU).
Fuqua Standards Track