Operating instructions

220 Cisco Systems Intelligent Gigabit Ethernet Switch Module
show spanning-tree blockedports
This command is important for showing what ports are blocked and which are forwarding
before a problem starts. Should be predictable under all link up/down conditions.
A switch with two Etherchannel ports (Po1 and Po2) with the root switch connected to Po1:
cigesm_t#sh spanning-tree blockedports
Name Blocked Interfaces List
-------------------- ------------------------------------
VLAN0001 Po2
VLAN0777 Po2
VLAN0778 Po2
VLAN0779 Po2
Number of blocked ports (segments) in the system : 4
show spanning-tree root
Figure 8-11 shows some of the attributes of the show span root command. Like the show
span blocked command, it is important to check your spanning tree when its working
correctly, so if things fail you can see the changes in forwarding and blocking.
Figure 8-11 Output from the show span root command
show link state group detail
This show link state group detail reports on the configuration and status of the trunk failover
feature.
Switch#show link state group detail
Link State Group: 1 Status: Enabled, Up
Upstream Interfaces : Po1(Up) Po2(Up)
Downstream Interfaces : Gi0/1(Up) Gi0/2(Up) Gi0/3(Up) Gi0/4(Up)
Gi0/5(Up) Gi0/6(Up) Gi0/7(Up) Gi0/8(Up) Gi0/9(Up) Gi0/10(Up)
Gi0/11(Up) Gi0/12(Up) Gi0/13(Up) Gi0/14(Up)
Link State Group: 2 Status: Disabled, Down
• Somewhat of the inverse of the show span blocked
command
• Important to know what ports are closest to the root
switch
cigesm_t#sh spanning-tree root
Root Hello Max Fwd
Vlan Root ID Cost Time Age Dly Root Port
---------------- -------------------- ------ ----- --- --- ----------------
VLAN0001 32768 000f.f88c.6c00 31 2 20 15
VLAN0002 32770 000f.90cd.6fc0 0 2 20 15
VLAN0030 32798 000f.90cd.6fc0 0 2 20 15
VLAN0110 32878 000f.90cd.6fc0 0 2 20 15
VLAN0777 32768 000f.f88c.6f08 31 2 20 15 Po1
VLAN0778 32768 000f.f88c.6f09 31 2 20 15 Po1
VLAN0779 32768 000f.f88c.6f0a 31 2 20 15 Po1
VLAN4094 36862 000f.90cd.6fc0 0 2 20 15
In this example, VLANs not carried
off of this switch
This switch is root for these VLANs
so there is no entry in “Root port”
VLANs carried off of this switch, Po1 in this design
is the closest connection to the root switch