173region to become the CST.The MSTI is only valid within its MST region. An MSTI has nothing to do with MSTIs inother MST regions. The bridges in a MST region receive the MST BPDU of other regionsthrough Boundary Ports. They only process CIST related information and abandon MSTIinformation.6.1.2 Port RolesThe MSTP bridge assigns a port role to each port which runs MSTP. CIST port roles: root port, designated port, alternate port and backup port On top of those roles, each MSTI port has one new role: master port.The port roles in the CIST (root port, designated port, alternate port and backup port)are defined in the same ways as those in the RSTP.6.1.3MSTP Load BalanceIn a MSTP region, VLANs can by mapped to various instances. That can form varioustopologies. Each instance is independent from the others and each distance can has itsown attributes such as bridge priority and port cost etc. Consequently, the VLANs indifferent instances have their own paths. The traffic of the VLANs are load-balanced.6.2 Configuring MSTP6.2.1 MSTP Configuration Task Sequence1. Enable the MSTP and set the running mode2. Configure instance parameters3. Configure MSTP region parameters4. Configure MSTP time parameters5. Configure the fast migrate feature for MSTP1. Enable MSTP and set the running modeCommand ExplanationGlobal Mode and Interface Mode
