Huawei quidway s7700 - Page 439

Figure 9-2 MST region
D0
S1
other VLANs MSTI0
S2
S4
S3
VLAN1 MSTI1
VLAN2,VLAN3 MSTI2
MSTI1
root switch:S3
MSTI2
root switch:S2
MSTI0 (IST)
root switch:S1
AP1
Master Bridge
l VLAN mapping table
The VLAN mapping table is an attribute of the MST region. It describes mappings between
VLANs and MSTIs.
Figure 9-2 shows the mappings in the VLAN mapping table of the MST region D0:
– VLAN 1 is mapped to MSTI 1.
– VLAN 2 and VLAN 3 are mapped to MSTI 2.
– Other VLANs are mapped to MSTI 0.
l Regional root
Regional roots are classified into Internal Spanning Tree (IST) and MSTI regional roots.
In the region B0, C0, and D0 on the network shown in Figure 9-4, the switching devices
closest to the Common and Internal Spanning Tree (CIST) root are IST regional roots.
An MST region can contain multiple spanning trees, each called an MSTI. An MSTI
regional root is the root of the MSTI. On the network shown in Figure 9-3, each MSTI has
its own regional root.
Quidway S7700 Smart Routing Switch
Configuration Guide - Ethernet 9 MSTP Configuration
Issue 01 (2011-07-15) Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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