H3C S7500 Series Operation Manual page 282

Operation Manual – MSTP
H3C S7500 Series Ethernet Switches
Some other vendors' switches adopt proprietary spanning tree protocols that are similar
to RSTP in the way to implement rapid transition on designated ports. When a switch of
this kind operating as the upstream switch connects with the H3C series switch running
MSTP, the upstream designated port fails to change their states rapidly.
The rapid transition function is developed to resolve this problem. When a H3C series
switch running MSTP is connected ins the upstream direction to another vendor's
switch running a proprietary spanning tree protocol, you can enable the rapid transition
function on the ports of the H3C series switch operating as the downstream switch.
Among these ports, those operating as the root ports will then send agreement packets
to their upstream ports after they receive proposal packets from the upstream
designated ports, instead of waiting for agreement packets from the upstream switch.
This enables designated ports of the upstream switch to change their states rapidly.
1.7.2 Rapid Transition Configuration
I. Configuration prerequisites
As shown in
The former operates as the downstream switch, and the latter operates as the
upstream switch. The network operates normally.
The upstream switch is running a proprietary spanning tree protocol that is similar to
RSTP in the way to implement rapid transition on designated ports. Port 1 is a
designated port.
The downstream switch is running MSTP. Port 2 is the root port.
Third-party device
Port 2
Device A
Figure 1-5 Network diagram for rapid transition configuratio
II. Configuration procedure
1) Configure the rapid transition function in system view.
Follow these steps to configure the rapid transition function in system view:
Figure 1-5, a H3C series switch is connected to another vendor's switch.
Port 1
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Chapter 1 MSTP Configuration
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