Configuring MSTP 189

Figure 54 Port Roles

MSTP Principles

MSTP divides the entire Layer 2 network into several MST regions, and calculates

 

and generates CST for them. Multiple spanning trees are generated in a region

 

and each of them is called an MSTI. The instance 0 is called IST, and others are

 

called MSTI.

 

CIST calculation

 

The CIST root is the highest-priority switch, elected from the switches on the entire

 

network by comparing their configuration BPDUs. MSTP calculates and generates

 

an IST in an MST region and also the CST connecting the regions. CIST is the

 

unique single spanning tree of the entire switching network.

 

MSTI calculation

 

Inside an MST region, MSTP generates different MSTIs for different VLANs

 

according to the association between the VLAN and the spanning tree.

 

In this way, the packets of a VLAN travel along the corresponding MSTI; inside the

 

MST region and the CST between different regions.

 

 

Configuring MSTP

Configuring MSTP includes tasks that are described in the following sections:

 

Configuring the MST Region for a Switch

 

Specifying the Switch as Primary or Secondary Root Switch

 

Configuring the MSTP Running Mode

 

Configuring the Bridge Priority for a Switch

 

Configuring the Max Hops in an MST Region

 

Configuring the Switching Network Diameter

 

Configuring the Time Parameters of a Switch

 

Configuring the Max Transmission Speed on a Port

 

Configuring a Port as an Edge Port

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3Com 10014298 manual Configuring Mstp, Mstp Principles, Cist calculation, Msti calculation