Siemens S223, S323 user manual Configuring STP/RSTP/MSTP/PVSTP/PVRSTP Mode Required, Region a IST

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

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

Switch A

Region C (IST)

Switch B

Region B (IST)

CST Root & IST Root

IST Root Switch C

Instance 2		Instance 1
Instance 2		IST Root
Instance 3		Region A (IST)
Switch D	Switch E

Fig. 8.23 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.

8.3.4Configuring STP/RSTP/MSTP/PVSTP/PVRSTP Mode (Required)

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.

Command	Mode	Description
stp force-version {stp rstp	Bridge	Configures Force-version in the bridge.
mstp pvstp pvrstp}

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

Command	Mode	Description
no stp force-version	Bridge	Removes force-version configuration.

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