Adding an auto-configure stacked-vlan-ranges causes an FPC to crash

When attempting to add a second vlan range (stacked vlans) under an auto-configure setting, a commit configuration command will cause an FPC to crash if the second outer vlan range is included in the first outer vlan range.

This issue is reported in Junos OS 12.3R5.

Combinations that can trigger an FPC crash

The two examples below can cause an FPC to crash:

The second outer vlan range (1-10) includes the first outer vlan range (6-9). Therefore, the inner vlan range must be different, or an error will be reported when you run a commit configuration command.

Combinations that will not trigger an FPC crash

The three examples below will not cause an FPC to crash:

1. If the beginning or ending number of the range of the second outer vlan is the same as the beginning or ending number of the range of the first outer vlan, the FPC will not crash. This acceptable combination is shown below:

  • first outer vlan range 1-5, second outer vlan range 1-10
  • first outer vlan range 6-10, second outer vlan range 1-10

2. If the range of the second outer vlan overlaps the range of the first outer vlan, the FPC will not crash. This acceptable combination is shown below:

  • first outer vlan range 6-15, second outer vlan range 1-10

3 .If the range of the second outer vlan is different from the range of the first outer vlan, the FPC will not crash. In this case, the setting of the range of the inner vlan is inconsequential.

If this combination were to cause an FPC to crash, any subsequent change in the range of the vlan would cause the FPC to crash again. This situation is shown in the result of a backtrace command (below).

Insert the second vlan range before the first vlan range prior to running a commit configuration command, as shown below:

Doing this can help prevent an FPC from crashing. This issue is fixed in Junos OS 12.3R6 or later.

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Prasanna

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