Allied Telesis AT-S94 - Manual (Page 140)

Configuring Spanning Tree
Configuring Rapid Spanning Tree
Page 140
Configuring Rapid Spanning Tree
While Classic STP prevents Layer 2 forwarding loops in a general network topology, convergence can take
between 30-60 seconds. This time may delay detecting possible loops and propagating status topology changes.
Rapid Spanning Tree Protocol (RSTP) detects and uses network topologies that allow a faster STP convergence
without creating forwarding loops.
To define RSTP on the device:
1. Click Layer 2 > RSTP. The RSTP Page opens:
Figure 92: RSTP Page
The RSTP Page contains the following fields:
• Select the interfaces displayed in the table.
– Ports of Unit — Specifies the port and stacking member for which the RSTP settings are displayed.
– Trunk — Specifies the trunk for which the RSTP settings are displayed.
• Interface — Displays the port or trunk on which Rapid STP is enabled.
• Role — Displays the port role assigned by the STP algorithm to provide to STP paths. The possible field
values are:
– Root — Provides the lowest cost path to forward packets to the root switch.
– Designated — The port or trunk through which the designated switch is attached to the LAN.
– Alternate — Provides an alternate path to the root switch from the root interface.
– Backup — Provides a backup path to the designated port path toward the Spanning Tree leaves. Backup
ports occur only when two ports are connected in a loop by a point-to-point link, or when a LAN has two
or more connections to a shared segment.
– Disabled — The port is not participating in the Spanning Tree.