Configuring Rapid Transition - 3Com 4200G 12-Port Configuration Manual

Some other manufacturers' 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 a 3com switch running MSTP, the upstream designated port fails to
change its state rapidly.
The rapid transition feature is developed to resolve this problem. When a 3com switch running MSTP is
connected in the upstream direction to another manufacturer's switch running proprietary spanning tree
protocols, you can enable the rapid transition feature on the ports of the 3com 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.

Configuring Rapid Transition

Configuration prerequisites
As shown in Figure
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 the designated port.
The downstream 3com switch is running MSTP. Port 2 is the root port.
Figure 1-8 Network diagram for rapid transition configuration
Configuration procedure
1) Configure the rapid transition feature in system view
Follow these steps to configure the rapid transition feature in system view:
To do...
Enter system view
Enable the rapid transition
feature
2) Configure the rapid transition feature in Ethernet port view
Follow these steps to configure the rapid transition feature in Ethernet port view:
1-8, a 3com switch is connected to another manufacturer's switch. The former
Use the command...
system-view
stp interface interface-type
interface-number
no-agreement-check
1-41
Remarks
—
Required
By default, the rapid transition
feature is disabled on a port.