概念
MSTP: multiple spanning tree protocol
MSTP兼容RSTP和STP，既可以快速收敛，又提供了数据转发的多条冗余链路；数据转发过程中实现vlan数据的
负载均衡
MST 域
Multiple spanning tree region: 由交换网络中多台网络设备及之间的网段构成
MSTI
MST域内可以生成多颗生成树，每颗生成树都称为一个MSTI
每个MSTI 都是相互独立的，且每个MSTI的计算过程和RSTP计算过程是相同的
一个MSTI可以有多个VLAN
一个VLAN只能存在于一个MSTI
每个MSTI都有一个唯一的MSTID
交换机默认MSTI
[SW1]display stp region-configuration
Oper configuration
Format selector :0
Region name :4c1fcc0928c7
Revision level :0
Instance VLANs Mapped
0 1 to 4094
[SW1] User interface con0 is available
配置方法
[SW1]stp reg
[SW1]stp region-configuration ?
<cr>
[SW1]stp region-configuration #### 进入配置窗口
[SW1-mst-region]region-name aa #### 配置域名
[SW1-mst-region]revision-level 1 #### 配置修订号; 域名+修订号，定义一个域
[SW1-mst-region]instance 1 vlan 10 20 #### 实例1 关联 10 20
[SW1-mst-region]instance 2 vlan 30 40 #### 实例2 关联 30 40
[SW1-mst-region]display this #### 未激活，无法查看配置
#
return
[SW1-mst-region]active region-configuration ?
<cr>
[SW1-mst-region]active region-configuration #### 配置指令激活
Info: This operation may take a few seconds. Please wait for a moment...done.
[SW1-mst-region]display this #### 激活后方可查看配置
#
stp region-configuration
region-name aa
revision-level 1
instance 1 vlan 10 20
instance 2 vlan 30 40
active region-configuration
#
return
[SW1-mst-region]
查看某一实例指令
[SW1-mst-region]display stp instance 1
-------[MSTI 1 Global Info]-------
MSTI Bridge ID :32768.4c1f-cc09-28c7
MSTI RegRoot/IRPC :32768.4c1f-cc09-28c7 / 0
MSTI RootPortId :0.0
Master Bridge :32768.4c1f-cc09-28c7
Cost to Master :0
TC received :1
TC count per hello :0
Time since last TC :0 days 0h:0m:55s
Number of TC :4
Last TC occurred :GigabitEthernet0/0/2
----[Port1(GigabitEthernet0/0/1)][FORWARDING]----
Port Role :Designated Port
Port Priority :128
Port Cost(Dot1T ) :Config=auto / Active=20000
Designated Bridge/Port :32768.4c1f-cc09-28c7 / 128.1
Port Times :RemHops 20
TC or TCN send :7
TC or TCN received :0
----[Port2(GigabitEthernet0/0/2)][FORWARDING]----
Port Role :Designated Port
Port Priority :128
Port Cost(Dot1T ) :Config=auto / Active=20000
Designated Bridge/Port :32768.4c1f-cc09-28c7 / 128.2
Port Times :RemHops 20
TC or TCN send :1
TC or TCN received :1
----[Port3(GigabitEthernet0/0/3)][FORWARDING]----
Port Role :Designated Port
Port Priority :128
Port Cost(Dot1T ) :Config=auto / Active=20000
Designated Bridge/Port :32768.4c1f-cc09-28c7 / 128.3
Port Times :RemHops 20
TC or TCN send :0
TC or TCN received :0
----[Port4(GigabitEthernet0/0/4)][FORWARDING]----
Port Role :Designated Port
Port Priority :128
Port Cost(Dot1T ) :Config=auto / Active=20000
Designated Bridge/Port :32768.4c1f-cc09-28c7 / 128.4
Port Times :RemHops 20
TC or TCN send :0
TC or TCN received :0
查看域配置信息
[SW1]display stp region-configuration
Oper configuration
Format selector :0
Region name :aa
Revision level :1
Instance VLANs Mapped
0 1 to 9, 11 to 19, 21 to 29, 31 to 39, 41 to 4094
1 10, 20
2 30, 40
站在instance 1角度，配置根桥
[SW2]stp priority ?
INTEGER<0-61440> Bridge priority, in steps of 4096
[SW2]stp instance 1 ?
priority Specify bridge priority
root Specify root switch
[SW2]stp instance 1 ro
[SW2]stp instance 1 root ?
primary Primary root switch
secondary Secondary root switch
[SW2]stp instance 1 root primary
站在instance1角度，配置secondary
[SW3]stp instance 1 root secondary
查看instance1实例根桥配置
[SW2]display stp instance 1
-------[MSTI 1 Global Info]-------
MSTI Bridge ID :0.4c1f-ccb4-7d02
MSTI RegRoot/IRPC :0.4c1f-ccb4-7d02 / 0
MSTI RootPortId :0.0
MSTI Root Type :Primary root
Master Bridge :32768.4c1f-cc09-28c7
Cost to Master :20000
TC received :3
TC count per hello :0
Time since last TC :0 days 0h:10m:22s
Number of TC :4
Last TC occurred :GigabitEthernet0/0/2
----[Port2(GigabitEthernet0/0/2)][FORWARDING]----
Port Role :Designated Port
Port Priority :128
Port Cost(Dot1T ) :Config=auto / Active=20000
Designated Bridge/Port :0.4c1f-ccb4-7d02 / 128.2
Port Times :RemHops 20
TC or TCN send :2
TC or TCN received :3
站在instance2角度，配置根桥
[SW3]stp instance 2 root primary
站在instance2角度，配置secondary
[SW2]stp instance 2 root secondary
查看instance2实例根桥配置
[SW3]display stp instance 2
-------[MSTI 2 Global Info]-------
MSTI Bridge ID :0.4c1f-cc96-578d
MSTI RegRoot/IRPC :0.4c1f-cc96-578d / 0
MSTI RootPortId :0.0
MSTI Root Type :Primary root
Master Bridge :32768.4c1f-cc09-28c7
Cost to Master :20000
TC received :2
TC count per hello :0
Time since last TC :0 days 0h:13m:1s
Number of TC :4
Last TC occurred :GigabitEthernet0/0/1
----[Port1(GigabitEthernet0/0/1)][FORWARDING]----
Port Role :Designated Port
Port Priority :128
Port Cost(Dot1T ) :Config=auto / Active=20000
Designated Bridge/Port :0.4c1f-cc96-578d / 128.1
Port Times :RemHops 20
TC or TCN send :1
TC or TCN received :2
----[Port2(GigabitEthernet0/0/2)][FORWARDING]----
Port Role :Designated Port
Port Priority :128
Port Cost(Dot1T ) :Config=auto / Active=20000
Designated Bridge/Port :0.4c1f-cc96-578d / 128.2
Port Times :RemHops 20
TC or TCN send :3
TC or TCN received :0
站在接入层交换机，查看不同实例接口阻塞状态
[SW1]display stp brief
MSTID Port Role STP State Protection
0 GigabitEthernet0/0/1 DESI FORWARDING NONE
0 GigabitEthernet0/0/2 DESI FORWARDING NONE
0 GigabitEthernet0/0/3 DESI FORWARDING NONE
0 GigabitEthernet0/0/4 DESI FORWARDING NONE
0 GigabitEthernet0/0/5 DESI FORWARDING NONE
0 GigabitEthernet0/0/6 DESI FORWARDING NONE
1 GigabitEthernet0/0/1 ROOT FORWARDING NONE
1 GigabitEthernet0/0/2 ALTE DISCARDING NONE
1 GigabitEthernet0/0/3 DESI FORWARDING NONE
1 GigabitEthernet0/0/4 DESI FORWARDING NONE
2 GigabitEthernet0/0/1 ALTE DISCARDING NONE
2 GigabitEthernet0/0/2 ROOT FORWARDING NONE
2 GigabitEthernet0/0/5 DESI FORWARDING NONE
2 GigabitEthernet0/0/6 DESI FORWARDING NONE
