Operation Manual – MSTP
H3C S3610&S5510 Series Ethernet Switches
Chapter 1 MSTP Configuration
1-44
III. Configuration procedure
1)
Enable Digest Snooping on Device A
# Enable Digest Snooping on Ethernet 1/0/1.
<DeviceA> system-view
[DeviceA] interface Ethernet 1/0/1
[DeviceA-Ethernet1/0/1] stp config-digest-snooping
# Enable global Digest Snooping.
[DeviceA-Ethernet1/0/1] quit
[DeviceA] stp config-digest-snooping
2)
Enable Digest Snooping on Device B (the same as above, omitted)
1.8 Configuring No Agreement Check
Two types of messages are used for rapid state transition on designated RSTP and
MSTP ports:
z
Proposal: sent by designated ports to request rapid transition
z
Agreement: used to acknowledge rapid transition requests
Both RSTP and MSTP switches can perform rapid transition operation on a designated
port only when the port receives an agreement packet from the downstream switch.
The differences between RSTP and MSTP switches are:
z
For MSTP, the downstream device’s root port sends an agreement packet only
after it receives an agreement packet from the upstream device.
z
For RSTP, the down stream device sends an agreement packet regardless of
whether an agreement packet from the upstream device is received.
show the rapid state transition mechanism on MSTP and
RSTP designated ports.
Root port
Designated port
Root port blocks other
non-edge ports
Root port changes to
forwarding state and
sends Agreement
Downstream switch
Upstream Switch
Agreement
Proposal for rapid transition
Designated port
changes to
forwarding state
Agre
eme
nt
Figure 1-9
Rapid state transition of an MSTP designated port
