Black Box LGB1048A, Руководство пользователя

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User Manual
Publication date: Feb., 2008
Revision A1
105
3-13-3. STP Port Configuration
Function name:
STP Port Setting
Function description:
In the STP Port Setting, one item selection and five parameters settings are
offered for user’s setup. User can disable and enable each port by selecting
each Port Status item. User also can set “Path Cost” and “Priority” of each port
by filling in the desired value and set “Admin Edge Port” and “Admin Point To
Point” by selecting the desired item.
Parameter description:
Port Status:
It displays the current state of a port. We cannot manually set it because
it displays the status only. There are three possible states. ( according to
802.1w specification)
DISCARDING state indicates that this port can neither forward packets
nor contribute learning knowledge.
Notice: Three other states (Disable state, BLOCKING state and LISTENING
state) defined in the 802.1d specification are now all represented as
DISCARDING state.
LEARNING state indicates this port can now contribute its learning
knowledge but cannot forward packets still.
FORWARDING state indicates this port can both contribute its learning
knowledge and forward packets normally.
Path Cost Status:
It is the contribution value of the path through this port to Root Bridge.
STP algorithm determines a best path to Root Bridge by calculating the
sum of path cost contributed by all ports on this path. A port with a
smaller path cost value would become the Root Port more possibly.
Configured Path Cost:
The range is 0 – 200,000,000. In the switch, if path cost is set to be zero,
the STP will get the recommended value resulted from auto-negotiation
of the link accordingly and display this value in the field of Path Cost
Status. Otherwise, it may show the value that the administrator set up in
Configured Path Cost and Path Cost Status.