H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 83)

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Figure 19 Rapid state transition of an MSTP designated port
Figure 20 shows rapid state transition of an RSTP designated port.
Figure 20 Rapid state transition of an RSTP designated port
If the upstream device is a third-party device, the rapid state transition implementation may be limited.
For example, when the upstream device uses a rapid transition mechanism similar to that of RSTP, and the
downstream device adopts MSTP and does not work in RSTP mode, the root port on the downstream
device receives no agreement packet from the upstream device and sends no agreement packets to the
upstream device. As a result, the designated port of the upstream device fails to transit rapidly and can
only change to the forwarding state after a period twice the Forward Delay.
You can enable the No Agreement Check feature on the downstream device’s port to enable the
designated port of the upstream device to transit its state rapidly.
Configuration Prerequisites
Before you configure the No Agreement Check function, complete the following tasks:
• Connect a device to a third-party upstream device supporting spanning tree protocols via a
point-to-point link.
• Configure the same region name, revision level and VLAN-to-instance mappings on the two devices,
assigning them to the same region.
Configuring the No Agreement Check function
To make the No Agreement Check feature take effect, enable it on the root port.
Follow these steps to configure No Agreement Check: