Siemens S223 User Manual

User Manual                                                                               UMN:CLI 
SURPASS hiD 6615 S223/S323 R1.5 

A50010-Y3-C150-2-7619                                                                         211 

In CST, A and B are the switches operating with STP and C, D and, E are those operating 
with MSTP. First, in CST, CIST is established to decide CST Root. After CST root is de-
cided, the closest switch to CST root is decided as IST root of the region. Here, CST root 
in IST is IST root. 

Legacy 802.1d

CST Root & IST Root

Switch A

Switch D

Switch C

Switch E

Instance 2

Instance 3

Instance 2

Instance 1

IST Root

Switch B

IST Root

 

CST and IST of MSTP (2) 

 

In above situation, if B operates with MSTP, B will send it’s BPDU to CST root and IST 
root in order to request itself to be CST root. However, if any BPDU having higher priority 
than that of B is sent, B cannot be CST root. 

For the hiD 6615 S223/S323, the commands configuring MSTP are also used to config-
ure STP and RSTP. 

 

First of all, you need to configure force-version to decide the mode before STP is config-
ured. To decide force-version of the switch, use the following command. 

  {stp | rstp | 

 | pvstp | pvrstp} 

Bridge 

Configures Force-version in the bridge. 

 

To delete STP configuration from the switch, use the following command. 

 

Bridge 

Removes force-version configuration.