Siemens Reyrolle 7SR5, Руководство пользователя

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Roles of the ports
The following roles are defined for the
ports:
•
Root port role (R): A root port is
connected with the root switch, i.e. it
has a logical connection with it. With
internal switches, 1 of the 2 ports
always has the role of a root port.
•
Designated port role (D): A desig-
nated port can also establish a
connection with the root switch, but
in a different way. 1 of the 2 ports of
the internal switch normally has the
designated port role.
•
Alternate port role (A): An alternate
port can establish a connection in
case of a failure. In stable operation,
there must be exactly 1 alternate port
in 1 device per ring. In the absence of
a port with this role in a ring, the
redundancy is not ensured. The ring
is open.
– According to IEEE 802.3 the
receive output window is -14
dBm to -31 dBm.
– According to IEEE 802 the
output window of the trans-
mitter is between -14 dBm and
-20 dBm.
Port states
In addition to the role played by them,
ports have states assigned to them. The
following states are defined:
•
Forwarding state (F): This is in normal
operation the state of the ports which
play the root or designated role, i.e.
payload telegrams are always trans-
mitted.
•
Discarding state (D): Discarding state
means that telegrams are discarded
and not forwarded. In normal opera-
tion, only the port with the alternate
role has this status.
•
Learning state (L): This state is not
available in the internal switches. The
switch structure is such that the port
does not require a learning phase.
Normal status
In our example, port 1 shows the role
alternate
and the status
designated
,
which means that this port does neither
accept nor transmit telegrams from and to
the device.
Instruments and Meters
8.2 Instruments
400 Reyrolle 7SR5, Transformer Protection Device, Device Manual
C53000-G7040-C015-1, Edition 11.2019