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Defining 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. The Global System LAG information displays the same field information as the
ports, but represent the LAG RSTP information. To define RSTP on the device:
1.
Click Advanced Setup > Spanning Tree > RSTP > RSTP. The RSTP Page opens:
Figure 50: RSTP Page
The RSTP Page contains the following fields:
•
Unit No. — Indicates the stacking member for which the STP interface parameters are displayed.
•
Interface — Displays the port or LAG on which Rapid STP is enabled.
•
State — Displays the current RSTP state of a port. If enabled, the port state determines what forwarding
action is taken on traffic. Possible port states are:
–
Disabled — Indicates that STP is currently disabled on the port. The port forwards traffic while learning
MAC addresses.
–
Blocking — Indicates that the port is currently blocked and cannot forward traffic or learn MAC
addresses. Blocking is displayed when Classic STP is enabled.
•
Role — Displays the port role assigned by the STP algorithm to provide to STP paths. The possible field val-
ues are:
–
Root — Provides the lowest cost path to forward packets to the root switch.
–
Designated — The port or LAG 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 connected to a shared segment.
Page 96
Configuring Spanning Tree
Defining Rapid Spanning Tree
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