H3C Technologies H3C S10500 Series Switches - Manual (Page 103)

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CAUTION:
•
With digest snooping enabled, in-the-same-region verification does not require comparison of
configuration digest, so the VLAN-to-instance mappings must be the same on associated ports.
• With global Digest Snooping enabled, modification of VLAN-to-instance mappings and removal of the
current region configuration via the undo stp region-configuration command are not allowed. You can
modify only the region name and revision level.
• To make Digest Snooping take effect, you must enable it both globally and on associated ports. To make
the configuration effective on all configured ports and while reducing impact on the network, enable
Digest Snooping on all associated ports first and then globally.
• To prevent loops, do not enable Digest Snooping on MST region edge ports.
• H3C recommends you to enable Digest Snooping first and then the spanning tree feature. To avoid
causing traffic interruption, do not configure Digest Snooping when the network is already working well.
Digest Snooping configuration example
1. Network requirements
As shown in Figure 23 :
• Device A and Device B connect to Device C, which is a third-party device. All these devices are in
the same region.
• Enable Digest Snooping on the ports of Device A and Device B that connect to Device C, so that the
three devices can communicate with one another.
Figure 23 Digest Snooping configuration
2. Configuration procedure
# Enable Digest Snooping on GigabitEthernet 1/0/1 of Device A and enable global Digest Snooping
on Device A.
<DeviceA> 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