OmniSwitch OS6860/OS6900/OS10K Troubleshooting Guide Part No.032996-00 Rev.A
AOS Release 7.X and 8.X January 2015
Alcatel-Lucent Page 43 of 148
OS6860-> show spantree vlan 2
Spanning Tree Parameters for Vlan 2
Spanning Tree Status : ON,
Protocol : IEEE Rapid STP,
mode : Per VLAN (1 STP per Vlan),
Priority : 32768 (0x8000),
Bridge ID : 8000-e8:e7:32:b3:49:11,
Designated Root : 8000-00:e0:b1:93:90:4e,
Cost to Root Bridge : 4,
Root Port : 1/1/1,
Next Best Root Cost : 4,
Next Best Root Port : 1/1/3,
TxHoldCount : 3,
Topology Changes : 1,
Topology age : 00:15:38,
Current Parameters (seconds)
Max Age = 20,
Forward Delay = 15,
Hello Time = 2
Parameters system uses when attempting to become root
System Max Age = 20,
System Forward Delay = 15,
System Hello Time = 2
Use the show spantree ports command to determine if the port is in forwarding or blocking and are in the
correct VLAN. Remember that in any LAN with physical path redundancy there must be at least one port in
blocking status. Knowledge of the ports which are usually in a blocking state, can be leveraged as a starting
point for troubleshooting. Has their state changed?
OS6860-> show spantree ports
Vlan Port Oper Status Path Cost Role Note
-----+-------+------------+---------+-------+---------
2 1/1/1 FORW 4 ROOT
2 1/1/2 DIS 0 DIS
2 1/1/3 BLK 4 ALT
OS6860-> show spantree ports active
Vlan Port Oper Status Path Cost Role Note
-----+-------+------------+---------+-------+---------
1 1/1/1 FORW 4 ROOT
1 1/1/3 BLK 4 ALT
If ports that should be in a blocking state are now forwarding, there are two likely causes. The first is that there
was a physical failure in a link that was previously forwarding. The second is that the BPDUs from the root are
being dropped. If it appears that BPDUs are being dropped, troubleshoot this as if it were any other packet
being dropped.
Use the show interfaces command to look for errors incrementing on the port as well as to verify duplex
settings match on either side of the link.
OS6860-> show interfaces 1/1/1
Chassis/Slot/Port 1/1/1 :
Operational Status : up,
Last Time Link Changed : Wed Jan 1 00:20:13 2014,
Number of Status Change: 1,
Type : Ethernet,
SFP/XFP : N/A,
EPP : Disabled,
Link-Quality : N/A,
MAC address : e8:e7:32:b3:49:18,
BandWidth (Megabits) : 1000, Duplex : Full,
Autonegotiation : 1 [ 1000-F 100-F 100-H 10-F 10-H ],
Long Frame Size(Bytes) : 9216,
Rx :
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