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3. Troubleshooting Functional Failures in Operation
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3.5 Layer 2 Network Communication Failure
3.5.1 Layer 2 Communication by VLAN Is Disabled
If layer 2 communication is disabled when using VLAN, isolate the problem using failure analysis method listed in the
following table.
(1) Checking VLAN status
Execute the show vlan command or execute the show vlan command with "detail" parameter specified and check
the VLAN status. Check items for each VLAN function are listed below.
(a) Check items common to all VLAN functions
• Confirm that the VLAN setting for the port is correct.
• Confirm that the port has been set up with the compatible mode. If the expected port does not belong to
the default VLAN (VLAN ID 1), check the setting below.
• Confirm that a port VLAN other than VLAN ID 1 is not assigned for the access VLAN or native VLAN.
• Confirm that the default VLAN setting is assigned for "allowed vlan" in the trunk port.
• Confirm that a mirror port is not assigned for.
• Confirm that VLANs with the function enabled (such as VLAN authentication [static] of IEEE802.1X
function, Web authentication [fixed VLAN mode], and MAC authentication) and VLANs with the function
disabled are not in the same trunk port.
(b) Check items for protocol VLAN
If protocol VLAN is in use, execute show vlan and confirm that the protocol is set correctly.
# show vlan
:
VLAN ID:100 Type:Protocol based Status:Up
Protocol VLAN Information Name:ipv4
EtherType:0800,0806 LLC: Snap-EtherType:
Learning:On Uplink-VLAN: Uplink-Block: Tag-Translation:
:
(c) Check items for MAC VLAN
• When using the MAC VLAN, execute the show vlan mac-vlan command to confirm that the MAC
address that is allowed the VLAN communication is set up correctly. The value in the parentheses indicates
the function that registers a MAC address.
[Function]
static: MAC address that is set with configuration.
dot1x: MAC address that is set with IEEE802.1X.
wa: MAC address that is set with Web authentication.
vaa: MAC address that is set with authentication VLAN.
# show vlan mac-vlan
:
VLAN ID:100 MAC Counts:4
0012.e200.0001 (static) 0012.e200.00:02 (static)
0012.e200.0003 (static) 0012.e200.00:04 (dot1x)
• Execute the show vlan mac-vlan command to confirm that the same MAC address on the layer 2
authentication has not been set up for different VLAN configuration. A MAC address with * (asterisk) means