ZyXEL Communications MES3500-24 用户手册

MES3500-24/24F 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. 

Path cost is the cost of transmitting a frame onto a LAN through that port. The recommended cost 
is assigned according to the speed of the link to which a port is attached. The slower the media, the 
higher the cost.  

STP Path Costs

Path Cost

4Mbps

250

100 to 1000

1 to 65535

Path Cost

10Mbps

100

50 to 600

1 to 65535

Path Cost

16Mbps

62

40 to 400

1 to 65535

Path Cost

100Mbps

19

10 to 60

1 to 65535