Symptom
When VLAN Load Balancing is configured, VLANs on the Primary Edge port will not appear last field on the "show interface trunk" (even the VLANs that should be forwarding on the Primary Edge):
TACK-130#show run int gig 2/1/1
Building configuration...
Current configuration : 163 bytes
!
interface GigabitEthernet2/1/1
switchport trunk allowed vlan 10,20,30
switchport mode trunk
rep segment 10 edge primary
rep block port -2 vlan 10,20,30
end
STACK-130#show rep topology
REP Segment 10
BridgeName PortName Edge Role
-------------------------------- ---------- ---- ----
STACK-130 Gi2/1/1 Pri Alt <<<<
CIRCUIT Gi1/1/2 Open
CIRCUIT Gi1/1/4 Alt
STACK-230 Gi2/1/1 Sec Open
STACK-130#show int gig 2/1/1 trunk
Port Mode Encapsulation Status Native vlan
Gi2/1/1 on 802.1q trunking 1
Port Vlans allowed on trunk
Gi2/1/1 10,20,30
Port Vlans allowed and active in management domain
Gi2/1/1 10,20,30
Port Vlans in spanning tree forwarding state and not pruned
Gi2/1/1 none <<<
STACK-130#
Packets coming in the Primary Edge port are punted to the CPU. High CPU utilization can be seen with the NGWC Learning Pr.
No MAC learning occurs on the Primary Edge port for the VLANs, and MATM Bulk Delete messages are seen for every packet when running the "debug matm all" command.
Conditions
VLAN Load balancing is configured with an specific VLAN list.
Workaround
Do not configured VLAN Load Balancing or use "rep block port -2 vlan all"
