H3C Technologies H3C S3100 Series Switches - Manual (Page 215)

Operation Manual – MSTP
H3C S3100-52P Ethernet Switch
Chapter 1 MSTP Configuration
1-40
Operation Command Description
Display the configuration
display
current-configuration You can execute this
command in any view.
Note:
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When the digest snooping feature is enabled on a port, the port state turns to the
discarding state. That is, the port will not send BPDU packets. The port is not
involved in the STP calculation until it receives BPDU packets from the peer port.
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The digest snooping feature is needed only when your switch is connected to
another manufacturer’s switches adopting proprietary spanning tree protocols.
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To enable the digest snooping feature successfully, you must first enable it on all the
ports of your switch that are connected to another manufacturer’s switches adopting
proprietary spanning tree protocols and then enable it globally.
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To enable the digest snooping feature, the interconnected switches and another
manufacturer’s switch adopting proprietary spanning tree protocols must be
configured with exactly the same MST region-related configurations (including
region name, revision level, and VLAN-to-MSTI mapping).
z
The digest snooping feature must be enabled on all the ports of your S3100-52P
Ethernet switches connected to another manufacturer's switches adopting
proprietary spanning tree protocols in the same MST region.
z
When the digest snooping feature is enabled globally, the VLAN-to-MSTI mapping
table cannot be modified.
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The digest snooping feature is not applicable to edge ports in an MST region.
1.7 Configuring Rapid Transition
1.7.1 Introduction
Designated ports of RSTP-enabled or MSTP-enabled switches use the following two
types of packets to implement rapid transition:
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Proposal packets: Packets sent by designated ports to request rapid transition
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Agreement packets: Packets used to acknowledge rapid transition requests
Both RSTP and MSTP specify that the upstream switch can perform rapid transition
operation on the designated port only when the port receives an agreement packet
from the downstream switch. The difference between RSTP and MSTP are:
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For MSTP, the upstream switch sends agreement packets to the downstream
switch; and the downstream switch sends agreement packets to the upstream
switch only after it receives agreement packets from the upstream switch.