H3C WA Series, Руководство по настройке, Страница: 56 / 76

7-30
[AP B-Ethernet1/0/1] stp config-digest-snooping
[AP B-Ethernet1/0/1] quit
[AP B] stp config-digest-snooping
Configuring No Agreement Check
In RSTP and MSTP, two types of messages are used for rapid state transition on designated ports:
z
Proposal: sent by designated ports to request rapid transition
z
Agreement: used to acknowledge rapid transition requests
Both RSTP and MSTP bridges can perform rapid transition on a designated port only when the port
receives an agreement packet from the downstream bridge. The differences between RSTP and MSTP
bridges are:
z
For MSTP, the downstream bridge’s root port sends an agreement packet only after it receives an
agreement packet from the upstream bridge.
z
For RSTP, the down stream bridge sends an agreement packet regardless of whether an
agreement packet from the upstream bridge is received.
Figure 7-7 shows the rapid state transition mechanism on MSTP designated ports.
Figure 7-7
Rapid state transition of an MSTP designated port
Root port
Designated port
Root port blocks
other non-edge port
Upstream device
Downstream device
Proposal for rapid transition
Agreement
Root port changes to
forwarding state and sends
Agreement to upstream device
Designated port
changes to
forwarding state
Figure 7-8 shows rapid state transition of an RSTP designated port.
Figure 7-8
Rapid state transition of an RSTP designated port
Root port
Designated port
Root port blocks other non-
edge ports, changes to
forwarding state and sends
agreement to upstream device
Upstream device
Downstream device
Proposal for rapid transition
Agree
ment
Designated port
changes to
forwarding state