H3C S3100 8C SI Operation Manual page 256

Operation Manual – MSTP
H3C S3100 Series Ethernet Switches
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.
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 role
Port state
Forwarding
Learning
Discarding
Connecting to the
common root bridge
Region boundary ports
Port 1
Master port
B
Designated port
Port 3
Root/
port/Master
port
√
√
√
Port 2
Alternate port
A
C
Port 5
Backup port
D
Port 4
Region
Designated
boundary
port
√
√
√
1-15
Chapter 1 MSTP Configuration
Port 6
Table 1-6 lists possible
Alternate
port
port
√
—
√
—
√ √
Backup
port
—
—
√