Figure 8-6 Master Port And Regional Edge Port - Huawei Quidway S9300 Configuration Manual

Quidway S9300 Terabit Routing Switch
Configuration Guide - Ethernet
From the aspect of sending the BPDU, a backup port is a port that is blocked after learning the
BPDU sent by itself. For forwarding traffic, a backup port, as a backup of the designated port,
provides a backup path from the root switch to the leaf node.
Master Port
A master port is the port on the shortest path among all paths that connect the MST region to
the CIST root. A master port is the port of a switch that connects the MST region to the CIST
root. As shown in
form an MST region. Port AP1 on S9300A has the least path cost to the CIST root among all
ports in the MST region; therefore, AP1 is the master port of the MST region.

Figure 8-6 Master port and regional edge port

Regional Edge Port
A regional edge port refers to:
l
l
The regional edge port plays the same role in the MSTI and the CIST during MSTP calculation.
That is, if the regional edge port functions as the master port in the CIST, it functions as the
master port in all other MSTIs.
As shown in
with other regions; therefore, they are all regional edge ports of the MST region.
Issue 03 (2009-08-20)
Figure 8-6, S9300A, S9300B, S9300C, S9300D and the links between them
S9300B
MST domain
Interface
blocked
A port that is located on the edge of an MST region and is connected to another MST region
Or a port that connects regions running STP and RSTP
Figure 8-6, ports AP1, DP1 and DP2 in the MST region are directly connected
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Connect to
the root
AP1
Master
S9300A
S9300D
DP1 DP2
8 MSTP Configuration
S9300C
8-7