Huawei Quidway S7700 Configuration Manual - Ethernet page 438

Quidway S7700 Smart Routing Switch
Configuration Guide - Ethernet
If MSTP is deployed in the LAN shown in
9-1.
Figure 9-1 Multiple spanning trees in an MST region
Host C
(VLAN3)
Host B
(VLAN2)
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l
Devices within the same VLAN can communicate with each other and packets of different
VLANs are load-balanced along different paths.
Basic MSTP Concepts
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Issue 01 (2011-07-15)
SwitchA
VLAN3
VLAN3
SwitchB
VLAN2
VLAN3
VLAN2
SwitchC
MSTI1 (root switch: SwitchD)
MSTI2 (root switch: SwitchF)
MSTI 1 uses Switch D as the root switching device to forward packets of VLAN 2.
MSTI 2 uses Switch F as the root switching device to forward packets of VLAN 3.
MST region
An MST region contains multiple switching devices and network segments between them.
The switching devices have the following characteristics:
– MSTP-enabled
– Same region name
– Same VLAN-to-instance mapping
– Same MSTP revision number
A LAN can comprise several MST regions that are directly or indirectly connected.
Multiple switching devices can be grouped into an MST region by using MSTP
configuration commands.
As shown in Figure 9-2, the MST region D0 contains the switching devices S1, S2, S3,
and S4, and has three MSTIs.
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Figure 9-1, MSTIs are generated, as shown in
SwitchD
VLAN2
VLAN2
VLAN2
VLAN3
SwitchE
VLAN2
VLAN2
VLAN3
VLAN3
VLAN3
SwitchF
VLAN2 --> MSTI1
VLAN3 --> MSTI2
9 MSTP Configuration
Host A
(VLAN2)
Host D
(VLAN3)
Figure
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