H3C s3600 series Command Manual page 252

&<1-10>, where &<1-10> means that you can provide up to 10 port indexes/port index ranges for this
argument.
Description
Use the stp interface config-digest-snooping command to enable the digest snooping feature on
specific ports.
Use the undo stp interface config-digest-snooping command to disable the digest snooping feature
on specific ports.
By default, the digest snooping feature is disabled on a port.
According to IEEE 802.1s, two interconnected MSTP switches can interwork with each other through
MSTIs in an MST region only when the two switches have the same MST region-related configuration.
Interconnected MSTP switches determine whether or not they are in the same MST region by checking
the configuration IDs of the BPDUs between them. (A configuration ID contains information such as
region ID and configuration digest.)
As some another manufacturer's switches adopt proprietary spanning tree protocols, they cannot
interwork with other switches in an MST region even if they are configured with the same MST
region-related settings as other switches in the MST region.
This kind of problems can be overcome by implementing the digest snooping feature. If a switch port is
connected to another manufacturer's switch that has the same MST region-related settings but adopts
a proprietary spanning tree protocol, you can enable the digest snooping feature on the port when it
receives BPDU packets from another manufacturer's switch. Then the switch considers these BPDU
packets to be from its own MST region and records the configuration digests carried in the BPDU
packets received from the switch, which will be put in the BPDU packets to be sent to the another
manufacturer's switch. In this way, the switch can interwork with another manufacturer's switches in an
MST region.
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