VigorSwitch P1280 User’s Guide
105
This above diagram shows the Ethernet architecture, LLC sub-layer and MAC sub-layer, which
are responded to the Data Link layer, and transceivers, which are responded to the Physical
layer in OSI model. In this section, we are mainly describing the MAC sub-layer.
L
L
o
o
g
g
i
i
c
c
a
a
l
l
L
L
i
i
n
n
k
k
C
C
o
o
n
n
t
t
r
r
o
o
l
l
(
(
L
L
L
L
C
C
)
)
Data link layer is composed of both the sub-layers of MAC and MAC-client. Here MAC client
may be logical link control or bridge relay entity.
Logical link control supports the interface between the Ethernet MAC and upper layers in the
protocol stack, usually Network layer, which is nothing to do with the nature of the LAN. So it
can operate over other different LAN technology such as Token Ring, FDDI and so on. Likewise,
for the interface to the MAC layer, LLC defines the services with the interface independent of
the medium access technology and with some of the nature of the medium itself.
The table above is the format of LLC PDU. It comprises four fields, DSAP, SSAP, Control and
Information. The DSAP address field identifies the one or more service access points, in which
the I/G bit indicates it is individual or group address. If all bit of DSAP is 1s, it’s a global
address. The SSAP address field identifies the specific services indicated by C/R bit (command
or response). The DSAP and SSAP pair with some reserved values indicates some well-known
services listed in the table below.
Содержание VigorSwitch P1280
Страница 1: ......
Страница 7: ...VigorSwitch P1280 User s Guide 1 P Pa ar rt t I I I In nt tr ro od du uc ct ti io on n ...
Страница 24: ...VigorSwitch P1280 User s Guide 18 This page is left blank ...
Страница 25: ...VigorSwitch P1280 User s Guide 19 P Pa ar rt t I II I S Sw wi it tc ch h L LA AN N ...
Страница 60: ...VigorSwitch P1280 User s Guide 54 This page is left blank ...
Страница 61: ...VigorSwitch P1280 User s Guide 55 P Pa ar rt t I II II I S Se ec cu ur ri it ty y ...
Страница 67: ...VigorSwitch P1280 User s Guide 61 P Pa ar rt t I IV V Q Qo oS S C Co on nf fi ig gu ur ra at ti io on n ...
Страница 78: ...VigorSwitch P1280 User s Guide 72 This page is left blank ...
Страница 79: ...VigorSwitch P1280 User s Guide 73 P Pa ar rt t V V P Po oE E C Co on nf fi ig gu ur ra at ti io on n ...
Страница 85: ...VigorSwitch P1280 User s Guide 79 P Pa ar rt t V VI I S Sy ys st te em m M Ma ai in nt te en na an nc ce e ...
Страница 103: ...VigorSwitch P1280 User s Guide 97 P Pa ar rt t V VI II I D Di ia ag gn no os st ti ic cs s ...