Technical data

44 Brocade 6910 Ethernet Access Switch Diagnostic Guide
53-1002348-02
Port loop detection
Port loop detection
Brocade port loop detection allows the Brocade device to detect loops and disable a port that is on
the receiving end of a loop. A loop is detected by sending test packet BPDUs.
Port loop detection show commands
show spanning-tree
Syntax: show spanning-tree [interface]
interface
ethernet unit/port
unit - Unit identifier. (Range: 1)
port - Port number. (Range: 1-12)
port-channel channel-id (Range: 1-12)
This command displays the loop detection configuration, as shown in the following example.
Console# show spanning-tree ethernet 1/1
Eth 1/ 1 Information
--------------------------------------------------------------
Admin Status : Enabled
Role : Root
State : Forwarding
Admin Path Cost : 0
Oper Path Cost : 100000
Priority : 128
Designated Cost : 0
Designated Port : 128.16
Designated Root : 32768.0001ECF8D8C6
Designated Bridge : 32768.0001ECF8D8C6
Forward Transitions : 1
Admin Edge Port : Auto
Oper Edge Port : Disabled
Admin Link Type : Auto
Oper Link Type : Point-to-point
Flooding Behavior : Enabled
Spanning-Tree Status : Enabled
Loopback Detection Status : Enabled
Loopback Detection Release Mode : Auto
Loopback Detection Trap : Disabled
Loopback Detection Action : Block
Root Guard Status : Disabled
BPDU Guard Status : Disabled
BPDU Guard Auto Recovery : Disabled
BPDU Guard Auto Recovery Interval : 300
BPDU Filter Status : Disabled
Configuration notes
A port is disabled only if a packet is looped back to that same port. Loop detection must be
configured on the physical port.