ZyXEL Communications 4728F User Manual

XGS-4526/4528F/4728F User’s Guide

The Switch supports Spanning Tree Protocol (STP), Rapid Spanning Tree Protocol 
(RSTP) and Multiple Spanning Tree Protocol (MSTP) as defined in the following 
standards. 

• IEEE 802.1D Spanning Tree Protocol
• IEEE 802.1w Rapid Spanning Tree Protocol
• IEEE 802.1s Multiple Spanning Tree Protocol

The Switch also allows you to set up multiple STP configurations (or trees). Ports 
can then be assigned to the trees.

(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.

The root bridge is the base of the spanning tree.