H3C S3100-52P Operation Manual page 260

Operation Manual – MSTP
H3C S3100-52P Ethernet Switch
MST region
Figure 1-5 Port roles
X. Port state
In MSTP, a port can be in one of the following three states:
Forwarding state. Ports in this state can forward user packets and receive/send
BPDU packets.
Learning state. Ports in this state can receive/send BPDU packets but do not
forward user packets.
Discarding state. Ports in this state can only receive BPDU packets.
Port roles and port states are not mutually dependent.
combinations of port states and port roles.
Table 1-6 Combinations of port states and port roles
Port
Port
state
Forwarding
Learning
Discarding
Connecting to the
common root bridge
Region boundary ports
Port 1
Master port
B
Designated port
Port 3
Root/mast
role
er port
√ √
√ √
√ √
Port 2
Alternate port
A
C
Port 5
Backup port
D
Port 4
Region
Designate
Boundary
d port
port
√
√
√
1-16
Chapter 1 MSTP Configuration
Port 6
Table 1-6 lists possible
Alternate Backup
port
— —
— —
√ √
port