单区域多生成树一个案例
交换机组网MSTP配置需要达到的效果
1、根选举是否正常
<QQT9F-B08-B-S6506-1>dis stp inst 0
-------[CIST Global Info][Mode MSTP]-------
CIST Bridge :0.000f-e218-d10c
Bridge Times :Hello 2s MaxAge 20s FwDly 15s MaxHop 20
CIST Root/ERPC :0.000f-e218-d10c / 0
CIST RegRoot/IRPC :0.000f-e218-d10c / 0
CIST RootPortId :0.0
BPDU-Protection :disabled
TC-Protection :enabled / Threshold=6
Bridge Config
Digest Snooping :disabled
CIST Root Type :PRIMARY root
TC or TCN received :89170
Time since last TC :0 days 0h:57m:19s
<QQT9F-B08-B-S6506-2>dis stp ins 0
-------[CIST Global Info][Mode MSTP]-------
CIST Bridge :4096.000f-e218-cf81
Bridge Times :Hello 2s MaxAge 20s FwDly 15s MaxHop 20
CIST Root/ERPC :0.000f-e218-d10c / 180
CIST RegRoot/IRPC :4096.000f-e218-cf81 / 0
CIST RootPortId :128.97
BPDU-Protection :disabled
TC-Protection :enabled / Threshold=6
Bridge Config
Digest Snooping :disabled
CIST Root Type :SECONDARY root
TC or TCN received :151059
Time since last TC :0 days 0h:12m:21s
<QQT10F-S3352-1>dis stp ins 0
-------[CIST Global Info][Mode MSTP]-------
CIST Bridge :32768.781d-ba80-2e68
Bridge Times :Hello 2s MaxAge 20s FwDly 15s MaxHop 20
CIST Root/ERPC :32768.781d-ba80-2e68 / 0
CIST RegRoot/IRPC :32768.781d-ba80-2e68 / 0
CIST RootPortId :0.0
BPDU-Protection :disabled
TC or TCN received :0
TC count per hello :0
STP Converge Mode :Normal
Time since last TC :3 days 23h:45m:19s
发现问题了，这里的3352优先级别是默认的32768，但是计算的结果是自己为根。
<QQT10F-S3352-2>dis stp ins 0
-------[CIST Global Info][Mode MSTP]-------
CIST Bridge :32768.781d-ba80-2e7f
Bridge Times :Hello 2s MaxAge 20s FwDly 15s MaxHop 20
CIST Root/ERPC :0 .000f-e218-d10c / 200179
CIST RegRoot/IRPC :32768.781d-ba80-2e7f / 0
CIST RootPortId :128.48
BPDU-Protection :disabled
TC or TCN received :115
TC count per hello :0
STP Converge Mode :Normal
Time since last TC :0 days 0h:42m:30s
2、MSTP区域配置是否正常
都是默认配置，单个交换机独立为一个区域。
<QQT9F-B08-B-S6506-1>dis stp reg
Oper configuration
Format selector :0
Region name :000fe218d10c
Revision level :0
Instance Vlans Mapped
0 1 to 899, 905 to 909, 911 to 918, 920 to 924, 926 to 936, 938 to
939, 951 to 954, 957 to 4094
1 900 to 904, 910, 919, 925, 937, 940 to 946, 948 to 949, 955 to
956
2 947, 950
<QQT9F-B08-B-S6506-2>dis stp reg
Oper configuration
Format selector :0
Region name :000fe218cf81
Revision level :0
Instance Vlans Mapped
0 1 to 899, 905 to 909, 911 to 918, 920 to 924, 926 to 939, 951 to
954, 957 to 4094
1 900 to 904, 910, 919, 925, 940 to 946, 948 to 949, 955 to 956
2 947, 950
<QQT10F-S3352-1>dis stp reg
Oper configuration
Format selector :0
Region name :781dba802e68
Revision level :0
Instance Vlans Mapped
0 1 to 949, 951 to 4094
2 950
<QQT10F-S3352-2>dis stp reg
Oper configuration
Format selector :0
Region name :781dba802e7f
Revision level :0
Instance Vlans Mapped
0 1 to 949, 951 to 4094
2 950
3、MSTP端口角色和转发状态是否正常
<QQT9F-B08-B-S6506-1>dis stp br
MSTID Port Role STP State Protection
0 Ethernet2/0/1 DESI FORWARDING NONE
0 Ethernet2/0/26 DESI FORWARDING NONE
1 Ethernet2/0/1 DESI FORWARDING NONE
1 Ethernet2/0/26 DESI FORWARDING NONE
2 Ethernet2/0/1 DESI FORWARDING NONE
2 Ethernet2/0/26 DESI FORWARDING NONE
<QQT9F-B08-B-S6506-2>dis stp br
MSTID Port Role STP State Protection
0 Ethernet2/0/1 ROOT FORWARDING NONE
0 Ethernet2/0/26 DESI FORWARDING NONE
1 Ethernet2/0/1 MAST FORWARDING NONE
1 Ethernet2/0/26 DESI FORWARDING NONE
2 Ethernet2/0/1 MAST FORWARDING NONE
2 Ethernet2/0/26 DESI FORWARDING NONE
<QQT10F-S3352-1>dis stp br
MSTID Port Role STP State Protection
0 Ethernet0/0/47 DESI FORWARDING NONE
0 Ethernet0/0/48 DESI FORWARDING NONE
2 Ethernet0/0/47 DESI FORWARDING NONE
2 Ethernet0/0/48 DESI FORWARDING NONE
3352－1认为自己为根，所有端口均为指定端口，是不正常的。
<QQT10F-S3352-2>dis stp br
MSTID Port Role STP State Protection
0 Ethernet0/0/47 DESI DISCARDING NONE
0 Ethernet0/0/48 ROOT FORWARDING NONE
2 Ethernet0/0/47 DESI DISCARDING NONE
2 Ethernet0/0/48 MAST FORWARDING NONE
4、处理方法：
搜集信息，报给华为800，厂家解决。
5、发现的问题：
MSTP的区域配置都是默认的配置（交换机主控板MAC地址），这样每个交换机都是独自一个区域，导致MSTP的多个MSTI实例的运算是无意义的（因为MSTI只在区域内运算），整个交换区域的MSTP树实质已经变成了CST公共生成树，区域内的生成树IST只有这台交换机自身，整个交换组网CIST实际已经变成了区域之间的CST域（instance 0）加上设备本身，导致新配置的instance实质还是和默认的instance 0 一起STP运算，无法独立控制。
MSTP概念图解
6、整改方法
网络不是很复杂的情况下，需要对区域内的VLAN做独立调整，就需要预先划定MSTP区域，并保证区域配置4要素（dis stp reg输出）的一致性。这样才能实现区域内不同的MSTI的不同选路控制。
[QQT10F-S3352-1]dis stp br
MSTID Port Role STP State Protection
0 Ethernet0/0/47 ROOT FORWARDING NONE
0 Ethernet0/0/48 ALTE DISCARDING NONE
2 Ethernet0/0/47 ROOT FORWARDING NONE
2 Ethernet0/0/48 ALTE DISCARDING NONE
修改上行链路instance 2的STP cost值，让实例2的VLAN走另外一边的交换机。
[QQT10F-S3352-1]dis stp br
MSTID Port Role STP State Protection
0 Ethernet0/0/47 ROOT FORWARDING NONE
0 Ethernet0/0/48 ALTE DISCARDING NONE
2 Ethernet0/0/47 ALTE DISCARDING NONE
2 Ethernet0/0/48 ROOT FORWARDING NONE
