Involved Products and Versions
All products and versions
Networking
As shown in Figure 1-1, SwitchA, SwitchB, and SwitchC are directly connected. L2PT is configured on SwitchB. STP packets need to be transparently transmitted from SwitchA to SwitchC through SwitchB.
Figure 1-1 Networking diagram for the L2PT failure
Fault Symptom
SwitchB fails to transparently transmit STP packets.
Troubleshooting Procedure
Step 1 Check the configurations of the interfaces GE0/0/1 and GE0/0/2 on SwitchB.
STP packets are transparently transmitted based on VLAN 1226, but the interface GE1/0/1 does not allow packets of VLAN 1226 to pass through. Therefore, transparent transmission fails.
#
interface GigabitEthernet1/0/1
port link-type hybrid
port hybrid tagged vlan 19 21
stp disable
l2protocol-tunnel stp vlan 1226
#
interface GigabitEthernet1/0/2
port link-type hybrid
port hybrid tagged vlan 1226
stp disable
l2protocol-tunnel stp vlan 1226
Run the port hybrid tagged vlan 1226 command on the interface GE1/0/1. The fault is rectified.
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Conclusions and Suggestions
When L2PT is enabled on an interface, the ID range of VLANs whose packets are allowed to pass through the interface must contain the VLAN IDs in the Layer 2 protocol packets.
