3Com 4200G 24-Port - Configuring Rapid Transition; Introduction

1-39
To do... Use the command... Remarks
Enter system view
system-view
—
Enter Ethernet port view
interface interface-type
interface-number
—
Enable the digest snooping
feature
stp config-digest-snooping
Required
The digest snooping feature is
disabled on a port by default.
Return to system view
quit
—
Enable the digest snooping
feature globally
stp config-digest-snooping
Required
The digest snooping feature is
disabled globally by default.
Display the current
configuration
display current-configuration
Available in any view
z 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.
z The digest snooping feature is needed only when your switch is connected to another
manufacturer’s switches adopting proprietary spanning tree protocols.
z 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.
z 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 switch ports that connect 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.
z The digest snooping feature is not applicable to boundary ports in an MST region.
z The digest snooping feature is not applicable to edge ports in an MST region.
Configuring Rapid Transition
Introduction
Designated ports of RSTP-enabled or MSTP-enabled switches use the following two types of packets to
implement rapid transition: