拓扑

配置多实例生成树，使同VLAN之间采用最优路径通信且不环路

TRUNK，ACCESS基础配置

LSW1

#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 8 to 9
#
interface GigabitEthernet0/0/2
 port link-type trunk
 port trunk allow-pass vlan 8 to 9
#
interface GigabitEthernet0/0/4
 port link-type access
 port default vlan 8

LSW2

#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 8 to 9
#
interface GigabitEthernet0/0/3
 port link-type trunk
 port trunk allow-pass vlan 8 to 9
#
interface GigabitEthernet0/0/4
 port link-type access
 port default vlan 9

LSW3

#
interface GigabitEthernet0/0/1
 port link-type access
 port default vlan 9
#
interface GigabitEthernet0/0/2
 port link-type trunk
 port trunk allow-pass vlan 8 to 9
#
interface GigabitEthernet0/0/3
 port link-type trunk
 port trunk allow-pass vlan 8 to 9
#
interface GigabitEthernet0/0/4
 port link-type access
 port default vlan 8
#
interface GigabitEthernet0/0/5
 port link-type access
 port default vlan 9

MSTP配置

LSW1

[LSW1]stp mode mstp 
#
stp region-configuration
 region-name gls
 revision-level 1
 instance 1 vlan 8
 instance 2 vlan 9
 active region-configuration
[LSW1]stp instance 1 priority 0
[LSW1]stp instance 2 priority 4096

LSW2

[LSW2]stp mode mstp 
#
stp region-configuration
 region-name gls
 revision-level 1
 instance 1 vlan 8
 instance 2 vlan 9
 active region-configuration
[LSW2]stp instance 1 priority 4096
[LSW2]stp instance 2 priority 0

LSW3

[LSW3]stp mode mstp 
#
stp region-configuration
 region-name gls
 revision-level 1
 instance 1 vlan 8
 instance 2 vlan 9
 active region-configuration

MSTP验证

LSW3

[LSW3]dis stp instance 1 brief 
 MSTID  Port                        Role  STP State     Protection
   1    GigabitEthernet0/0/2        ROOT  FORWARDING      NONE
   1    GigabitEthernet0/0/3        ALTE  DISCARDING      NONE
   1    GigabitEthernet0/0/4        DESI  FORWARDING      NONE
[LSW3]dis stp instance 2 b
 MSTID  Port                        Role  STP State     Protection
   2    GigabitEthernet0/0/2        ALTE  DISCARDING      NONE
   2    GigabitEthernet0/0/3        ROOT  FORWARDING      NONE
   2    GigabitEthernet0/0/5        DESI  FORWARDING      NONE

连通性测试

PC3 ping PC1
LSW3的GE0/0/2抓包

PC>ping 192.168.1.1

Ping 192.168.1.1: 32 data bytes, Press Ctrl_C to break
From 192.168.1.1: bytes=32 seq=1 ttl=128 time=62 ms

--- 192.168.1.1 ping statistics ---
  1 packet(s) transmitted
  1 packet(s) received
  0.00% packet loss
  round-trip min/avg/max = 62/62/62 ms

PC4 ping PC2
LS3的GE0/0/3抓包

PC>ping 192.168.1.2

Ping 192.168.1.2: 32 data bytes, Press Ctrl_C to break
From 192.168.1.2: bytes=32 seq=1 ttl=128 time=79 ms
From 192.168.1.2: bytes=32 seq=2 ttl=128 time=63 ms

--- 192.168.1.2 ping statistics ---
  2 packet(s) transmitted
  2 packet(s) received
  0.00% packet loss
  round-trip min/avg/max = 63/71/79 ms