3com S7906E Manuel De Montage

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Digest Snooping configuration example 
1) Network 
requirements 
z
 
Device A and Device B connect to Device C, a third-party device, and all these devices are in the 
same region. 
z
 
Enable Digest Snooping on Device A and Device B so that the three devices can communicate with 
one another. 
Figure 1-6 
Digest Snooping configuration 
 
 
2) Configuration 
procedure 
# Enable Digest Snooping on GigabitEthernet 2/0/1 of Device A and enable global Digest Snooping on 
Device A. 
<DeviceA> system-view 
[DeviceA] interface gigabitethernet 2/0/1 
[DeviceA-GigabitEthernet2/0/1] stp config-digest-snooping 
[DeviceA-GigabitEthernet2/0/1] quit 
[DeviceA] stp config-digest-snooping 
# Enable Digest Snooping on GigabitEthernet 2/0/1 of Device B and enable global Digest Snooping on 
Device B. 
<DeviceB> system-view 
[DeviceB] interface gigabitethernet 2/0/1 
[DeviceB-GigabitEthernet2/0/1] stp config-digest-snooping 
[DeviceB-GigabitEthernet2/0/1] quit 
[DeviceB] 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 devices can perform rapid transition on a designated port only when the port 
receives an agreement packet from the downstream device. The differences between RSTP and MSTP 
devices 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.