Table 13 Port Role And Port State - Zte ZXR10 2900 Series User Manual

ZXR10 2900 Series User Manual
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ports have the same cost to the root bridge, then the port with
the lowest port priority becomes to the root port.
� Designated: The port transmits data to switch downward, and
sends STP protocol message to maintain the state of STP.
� Backup: The port receives the STP message, which proves that
there exits a loop route to the port itself.
� Alternate: The port receives excess STP protocol message from
other equipment. However, when the original link abnormally
lost, the port under this state can transfer to transmitting state
and maintain the network instead of the port lapsed.
�
Edged: The port is used to connect the terminal equipment,
such as PC. The port does not participate in calculation before
STP is stable, and the state can be switched fast.
According to port role, the state after the calculation being steady
is shown in Table 13.
T 13 P R
ABLE ORT OLE AND
Port role
Master
Root
Designated
Backup
Alternate
Edged
BPDU protect function is for the protection of margin port. The
margin port will not receive the protocol message. If there exists
vicious protocol attack or Linux virtual bridge, receiving unlawful
protocol message will bring to net shocking or topology changing
abnormally. The port will be closed after using the protection.
After a while, to check the net is normal or not. If it is normal, it
will recover to original state.
Root protection is function is for the protection of root switch. In
the network that needs to appoint switch as root switch, if there
exists vicious protocol attack or Linux virtual bridge, it will bring
the change to the root and net abnormal. After using the root
protection of the port, if the port receives the protocol information
prior to root switch, it will transfer the port to blocking state. This
port no longer transmits message, and discards the received pro-
tocol message to protect the status of the root switch.
Loop protection function is for the protection of loop net topology.
In the network where ring exists, redundant topology will be in the
state of backup, and in the state of blocking after the port is steady.
If there is no need to transfer to transmission state, it is possible
to set port to loop protect. Once the port wants to transform, it
will inspire loop protection and set the port to blocking state.
P S
ORT TATE
Forward
Forward
Forward
Discard
Discard
Forward
Port state