Chapter 13 Monitor: Spanning Tree
GS1900 Series User’s Guide
79
13.2.5 STP Statistics
(R)STP detects and breaks network loops and provides backup links between switches, bridges or
routers. It allows a Switch to interact with other (R)STP-compliant switches in your network to
ensure that only one path exists between any two stations on the network.
The Switch uses IEEE 802.1w RSTP (Rapid Spanning Tree Protocol) that allows faster convergence
of the spanning tree than STP (while also being backwards compatible with STP-only aware
bridges). In RSTP, topology change information is directly propagated throughout the network from
the device that generates the topology change. In STP, a longer delay is required as the device that
causes a topology change first notifies the root bridge and then the root bridge notifies the
network. Both RSTP and STP flush unwanted learned addresses from the filtering database. In
RSTP, the port states are Discarding, Learning, and Forwarding.
Note: In this user’s guide, “STP” refers to both STP and RSTP.
Use this screen to view the Switch’s spanning tree STP statistics. Click Monitor > Spanning Tree
> STP Statistics to access this screen.
Figure 62 Monitor > Spanning Tree > STP Statistics
Indentifier (Priority
/ Port Id)
This field displays the identifier (in priority / port number).
Internal Path
Cost(Operation)
.
Regional Root
Bridge
Root bridge refers to the base of the spanning tree.
Internal Root Cost This field displays the internal root cost.
Designated Bridge For each LAN segment, a designated bridge is selected. This bridge has the lowest cost
to the root among the bridges connected to the LAN.
Port Role This field displays the state of the port role.
Port State This field displays the state of the port.
Table 44 Monitor > Spanning Tree > MST Port (continued)
LABEL DESCRIPTION
