1-33z Enable Digest Snooping on Device A’s and Device B’s ports that connect Device C, so that thethree devices can communicate with one another.Figure 1-8 Digest Snooping configurationGE1/0/2GE1/0/1GE1/0/2 GE1/0/2GE1/0/1GE1/0/1Device A Device BThird-party deviceRoot portDesignated portBlocked portDevice C2) Configuration procedure# Enable Digest Snooping on GigabitEthernet 1/0/1 of Device A and enable global Digest Snooping onDevice A. system-view[DeviceA] interface gigabitethernet 1/0/1[DeviceA-GigabitEthernet1/0/1] stp config-digest-snooping[DeviceA-GigabitEthernet1/0/1] quit[DeviceA] stp config-digest-snooping# Enable Digest Snooping on GigabitEthernet 1/0/1 of Device B and enable global Digest Snooping onDevice B. system-view[DeviceB] interface gigabitethernet 1/0/1[DeviceB-GigabitEthernet1/0/1] stp config-digest-snooping[DeviceB-GigabitEthernet1/0/1] quit[DeviceB] stp config-digest-snoopingConfiguring No Agreement CheckIn 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 transitionz Agreement: used to acknowledge rapid transition requestsBoth RSTP and MSTP devices can perform rapid transition on a designated port only when the portreceives an agreement packet from the downstream device. The differences between RSTP and MSTPdevices are:z For MSTP, the downstream device’s root port sends an agreement packet only after it receives anagreement packet from the upstream device.z For RSTP, the down stream device sends an agreement packet regardless of whether anagreement packet from the upstream device is received.Figure 1-9 shows the rapid state transition mechanism on MSTP designated ports.
