snap(6P) DG/UX 5.4.2 snap(6P)
NAME
snap - Subnetwork Access Protocol
DESCRIPTION
SNAP is part of the 802.1 layer. SNAP provides a way for protocols
that run over Ethernet to run over 802.x media. The SNAP sub-layer
contains a five byte header that can be used to specify additional
information for upper layers. The first three bytes of the header
represents an organizationally unique identifier (OUI) while the last
two bytes are locally administered. This structure allows different
vendors the flexibility to use the additional bytes of the header as
they wish.
One use of SNAP that has been commonly agreed upon is to use an OUI
of 0 to represent upper layer protocols that run over an Ethernet
based media. The two bytes that are locally administered are then
used to represent the two byte ether type field. In this manner,
protocols that run over Ethernet are able to use the SNAP layer to
run over 802.2 (LLC) and 802.x MAC layers. Data General provides the
SNAP functionality in the form of the SNAP pseudo-driver.
SEE ALSO
ifconfig(1M), netinit(1M), dgen(7), hken(7), inen(7), llc(7).
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