Sun Microsystems SunLink SNA 9.1 PU2.1, Руководство по настройке

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D-6 SunLink SNA 9.1 PU2.1 Server Configuration Guide—August 1997
D
purposes, since frames can only be sent from individual ring stations. For
more information about source routing, refer to Section D.3, “Source Routing
and Multiple-Ring Operation,” on page D-7.
Bit 1 of byte 0 indicates whether the address is being managed by the
network administrator or local management entity (locally administered) or
whether the addressing scheme is defaulting to the values assigned by the
IEEE and guaranteed to be unique (globally administered). Globally
administered addresses ensure that all the addresses for ring stations on the
network are unique. Locally administered addresses are useful when
various network management facilities are in use. For example, an office
number could be embedded in a station address so that the particular device
could be physically located given only its MAC address.
•
Group addresses - Occur only in the Destination Address of the Frame
Format and are used to identify multiple stations on the Token Ring. Frames
with default group addresses of
X'C000FFFFFFFF'
and
X'FFFFFFFFFFFF'
(known as broadcast addresses) are received by all stations on a Token Ring.
You can define additional group addresses, if desired.
•
Functional addresses - Special types of group addresses that are identified
by bytes 0 and 1 of the Destination Address being set to
X'C000'
, bit 0 of
byte 2 being set to 0, and one or more of the remaining 31 bits in bytes 2
through 5 being set as necessary. Each of these remaining 31 bits represents
network management functions, such as RPS and REM, and other optional
features, such as Token Ring bridges.
Sun's IBM Token Ring network connectivity products allow you to set the
Destination Address, Source Address, Group Address, and Functional
Address. The control of the Functional Address is included only for future use
and upward compatibility. When not used, the Functional Address recognition
feature is disabled. All Sun Token Ring network connectivity products
represent MAC addresses in hexadecimal format, such as
X'40001A67F527'
.
D.2.1.2 LLC Entities
LLC addresses are represented by SAPs and are one byte in length. The format
is shown in the following figure.