HP MSR SERIES Configuration Manual page 325

Figure 315 Port roles
MST region
In Figure 315, devices A, B, C, and D constitute an MST region. Port 1 and port 2 of device A are
connected to the common root bridge, port 5 and port 6 of device C form a loop, and port 3 and port
4 of Device D are connected downstream to the other MST regions.
Port states
In MSTP, the following states are available for a port:
Forwarding—The port learns MAC addresses and forwards user traffic.
•
• Learning—The port learns MAC addresses but does not forward user traffic.
Discarding—The port does not learn MAC addresses or forwards user traffic.
•
A port can have different port states in different MSTIs. A port state is not exclusively associated with a
port role. Table 141
is available for the corresponding port role and "—" indicates that the port state is not available for the
corresponding port role.)
Table 141 Ports states supported by different port roles
Port state
Forwarding
Learning
Discarding
Connecting to the common
root bridge
Boundary port
Port 1
Master port
A
B
D
Designated port
Port 3
lists the port states supported by each port role. ("Yes" indicates that the port state
Port role
Root port/master
port
Yes
Yes
Yes
Port 2
Alternate port
C
Port 6
Port 5
Backup port
Port 4
Designated
Boundary port
port
Yes Yes
Yes Yes
Yes Yes
308
Alternate port Backup port
— —
— —
Yes Yes