H3C S7500 Series Ethernet Switches Command Manual

Command Manual – MSTP
H3C S7500 Series Ethernet Switches Chapter 1
MSTP Configuration Commands
1-17
Parameters
interface-list: Ethernet port list. You can specify multiple Ethernet ports by providing this
argument in the form of interface-list ={ interface-type interface-number [ to
interface-type interface-number ] } &<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 function.
Use the undo stp interface config-digest-snooping command to disable the digest
snooping function.
By default, the digest snooping function is disabled.
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 other vendors' 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 problem can be overcome by implementing the digest snooping function. If a port
on an S7500 switch is connected to another vendor's switch that has the same MST
region-related settings as its own but adopts a proprietary spanning tree protocol, you
can enable digest snooping on the port. Then the S7500 switch regards the switch of
another vendor as in the same region; it records the configuration digests carried in the
BPDUs received from the switch of another vendor, and put them in the BPDUs to be
sent to the switch of another vendor. In this way, the S7500 switches can interwork with
other vendors' switches in the same MST region.