3com 4210 PWR 9-Port 3CR17341-91-ME 用户手册
产品代码
3CR17341-91-ME
178
C
HAPTER
14: MSTP C
ONFIGURATION
n
■
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.
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.
■
The digest snooping feature is needed only when your switch is connected to
another manufacturer’s switches adopting proprietary spanning tree protocols.
another manufacturer’s switches adopting proprietary spanning tree protocols.
■
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.
all the ports of your switch that are connected to another manufacturer’s
switches adopting proprietary spanning tree protocols and then enable it
globally.
■
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).
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).
■
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.
connect to another manufacturer’s switches adopting proprietary spanning
tree protocols in the same MST region.
■
When the digest snooping feature is enabled globally, the VLAN-to-MSTI
mapping table cannot be modified.
mapping table cannot be modified.
■
The digest snooping feature is not applicable to boundary ports in an MST
region.
region.
■
The digest snooping feature is not applicable to edge ports in an MST region.
Configuring Rapid
Transition
Transition
Introduction
Designated ports of RSTP-enabled or MSTP-enabled switches use the following
two types of packets to implement rapid transition:
two types of packets to implement rapid transition:
■
Proposal packets: Packets sent by designated ports to request rapid transition
■
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:
operation on the designated port only when the port receives an agreement
packet from the downstream switch. The difference between RSTP and MSTP are:
■
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.
switch; and the downstream switch sends agreement packets to the upstream
switch only after it receives agreement packets from the upstream switch.
■
For RSTP, the upstream switch does not send agreement packets to the
downstream switch.
downstream switch.
Display the current
configuration
configuration
display
current-configuration
current-configuration
You can execute this
command in any view.
command in any view.
Table 135 Configure digest snooping
Operation Command Description