Figure 49 Mstp Topological Structure - Zte ZXR10 2900 Series User Manual

cover many MST areas. User can divide the switches into a MST
area by using MSTP commands.
� Same area name.
� Same reversion level.
� Same mapping relationship between VLAN and instance.
� Switches should be connected directly.
There are many spanning trees can be configured in each MSTP
area, and they are independent each other. Each spanning tree
is Internal Spanning Tree (IST), and it can be called as Multiple
Spanning Tree Instance (MSTI). Common Spanning Tree connect
all MST areas in switching network. A MST area can be considered
as a switch, CST is a spanning tree which is generated by STP and
RSTP protocol calculation. All ISTs and CSTs are called as Common
and Internal Spanning Tree (CIST). CIST is a single spanning tree
to connect all switches.
In this MSTP topology structure, an IST can serve as a single bridge
(switch). In this way, CTS can serve as an RSTP for the interac-
tion of configuration information (BPDU). Multiple instances can
be created in an IST area and these instances are valid only in
this area. An instance is equivalent to an RSTP, except that the
instance needs to perform BPDU interaction with bridges outside
this area.
F 49 MSTP T
IGURE OPOLOGICAL
Spanning Tree Protocol (STP) can calculate according to the pro-
tocol. Ports are divided into different parts:
� Master: The port type is introduced in MSTP protocol. When
the multiple different areas exist, the main port is the minimal
path cost port point to the root.
� Root: The port that has the minimal cost to root bridge and
takes charge in forwarding data to root node. When multiple
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Chapter 7 Service Configuration
S
TRUCTURE
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