Installation manual

Operation Manual - STP
Quidway S3000-EI Series Ethernet Switches Chapter 1
MSTP Region-configuration
Huawei Technologies Proprietary
1-6
Switch A
with priority 0
Switch C
with priority 2
Switch B
with priority 1
CP2
BP2
CP1
BP1
AP2
AP1
4
10
5
Figure 1-4 Ethernet switch networking
arts of the configuration BPDU are
described in the example. They are root ID (expressed as Ethernet switch priority), path
rt of the switches will generate the configuration BPDU taking
th a root path cost as 0, designated switch IDs as their own switch
Configuration BPDU of AP1: {0, 0, 0, AP1}
BPDU of AP2: {0, 0, 0, AP2}
n BPDU of BP2: {1, 0, 1, BP2}
Configuration BPDU of CP2: {2, 0, 2, CP2}
the optimum configuration BPDU
DU to others. When a port receives a
configuration BPDU with a lower priority than that of its own, it will discard the message
n a higher-priority configuration BPDU is
e optimum configuration BPDU will be
To facilitate the descriptions, only the first four p
cost to the root, designated switch ID (expressed as Ethernet switch priority) and the
designated port ID (expressed as the port number). As illustrated in the figure above,
the priorities of Switch A, B and C are 0, 1 and 2 and the path costs of their links are 5,
10 and 4 respectively.
1) Initial state
When initialized, each po
itself as the root wi
IDs and the designated ports as their ports.
Switch A:
Configuration
Switch B:
Configuration BPDU of BP1: {1, 0, 1, BP1}
Configuratio
Switch C:
Configuration BPDU of CP1: {2, 0, 2, CP1}
2) Select
Every switch transmits its configuration BP
and keep the local BPDU unchanged. Whe
received, the local BPDU is updated. And th
elected through comparing the configuration BPDUs of all the ports.
The comparison rules are: