Draytek VigorSwitch G2240, Руководство пользователя, Страница: 121 / 156

VigorSwitch G2240 User’s Guide 115
2 2 . . 1 1 2 2 . . 3 3 P P o o r r t t
Function name:
STP Port Configuration
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.