H3C S3600 Series User Manual

Operation Manual – MSTP
H3C S3600 Series Ethernet Switches-Release 1510 Chapter 1
MSTP Configuration
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III. VLAN mapping table
A VLAN mapping table is a property of an MST region. It contains information about
how VLANs are mapped to MSTIs. For example, in
Figure 1-1, the VLAN mapping table
of region A0 is: VLAN 1 is mapped to MSTI 1; VLAN 2 is mapped to MSTI 2; and other
VLANs are mapped to CIST. In an MST region, load balancing is implemented
according to the VLAN mapping table.
IV. IST
An internal spanning tree (IST) is a spanning tree in an MST region.
ISTs together with the common spanning tree (CST) form the common and internal
spanning tree (CIST) of the entire switched network. An IST is a special MSTI; it is a
branch of CIST in the MST region. In
Figure 1-1, each MST region has an IST, which is
a branch of the CIST.
V. CST
A CST is a single spanning tree in a switched network that connects all MST regions in
the network. If you regard each MST region in the network as a switch, then the CST is
the spanning tree generated by STP or RSTP running on the "switches". In
Figure 1-1,
the lines in red depict the CST.
VI. CIST
A CIST is the spanning tree in a switched network that connects all switches in the
network. It comprises the ISTs and the CST. In
Figure 1-1, the ISTs in the MST regions
and the CST connecting the MST regions form the CIST.
VII. Region root
A region root is the root of the IST or an MSTI in an MST region. Different spanning
trees in an MST region may have different topologies and thus have different region
roots. In region D0 shown in
Figure 1-1, the region root of MSTI 1 is switch B, and the
region root of MSTI 2 is switch C.
VIII. Common root bridge
The common root bridge is the root of the CIST. The common root bridge of the network
shown in
Figure 1-1 is a switch in region A0.
IX. Port role
During MSTP calculation, the following port roles exist: root port, designated port,
master port, region edge port, alternate port, and backup port.
z A root port is used to forward packets to the root.
z A designated port is used to forward packets to a downstream network segment or
switch.

H3C S3600 Series Specifications

General

Brand	H3C
Model	S3600 Series
Category	Switch
Language	English