Technical information

AX Series L2 Loop Detection Configuration Guide (Edition 2)
Copyright © 2008, 2010, ALAXALA Networks Corporation. All rights reserved.
20
(2) Identification of loop location with the show loop-detection command
The status of L2 loops can be checked mainly with the show loop-detection command.
Example of executing the show loop-detection command
The following examples show display results for each actual loop pattern:
(a) Loop caused by connecting two port on the same switch device:
- A loop is created by connecting two ports on the same switch device.
- A loop is created by connecting a port on a switch device and a port on an intermediate device (such as a hub)
connected to the switch device.
- A loop is created by connecting two intermediate devices (such as hubs) linked to the same switch device.
In these cases, using the show loop-detection command results in the following display:
This indicates that port 0/5 is in the inact status because port 0/5 received an L2 loop detection frame from port
0/6 and that port 0/6 is in the inact status because port 0/6 received an L2 loop detection frame from port 0/5.
(b) Loop in the same port on the same switch device:
--- Date and time of command execution
--- L2 loop detection frame sending interval
--- Output transmission rate
--- Number of received L2 loop detection frames determined to be
loop detection
--- Received L2 loop detection frame hold time
--- Automatic-restoration time after being blocked
E1> sh loop-detection
Date 2008/06/26 17:43:54 UTC
Interval Time :1
Output Rate :30pps
Threshold :1
Hold Time :infinity
Auto Restore Time :-
VLAN Port Counts
Configuration :22 Capacity :30
Port Information
Port Status Type DetectCnt RestoringTimer SourcePort Vlan
0/1 Up uplink - - 0/24 12
0/2 Up uplink - - -
0/3 Down trap 0 - -
0/4 Down trap 0 - -
0/5 Down send-inact 0 - -
0/6 Down(loop) send-inact 20 - 0/6 10
0/7 Down send-inact 0 - -
No. of VLAN ports subject to L2 loop detection
No. of VLAN ports available for L2 loop detection
Port Port Port Current Time to automatic Source Source
No. status type detection count restoration port VLAN ID
0/6
0/5
0/5
0/6
0/5
0/6
- Connecting a hub under
the device to another port
on the device
- Connecting ports on the
same switchdevice
- Connecting hubs under
the device
>show loop-detection
...
Port Information
Port Status Type DetectCnt RestoringTimer SourcePort Vlan
0/5 Down(loop) send-inact 1 - 0/6 10
...
0/6 Down(loop) send-inact 1 - 0/5 10
--- Date and time of command execution
--- L2 loop detection frame sending interval
--- Output transmission rate
--- Number of L2 loop detection frames receivable until a loop is
detected
--- Received L2 loop detection frame hold time
--- Automatic-restoration time after being blocked