In Cisco 6509, every 12 1GE ports share a same ASIC and therefore are in a same port group, which would affect vlan mapping configuration.

1. When mapping vlans from 2 ports in the same (12-) group, The same mapping would be automatically spread over to all 12 ports. Therefore, the working configuration is to disable the vlan mapping in the port with translated vlan ID.

2. When mapping, only the destination (translated) vlan should be allowed in the local trunk port. The original vlan gets mapped as the first thing.

3. The mapping is strict one-to-one.

4. For communication over multiple ports with different VLAN IDs, the way to make mapping work is to wire the ports in different port group. Following example is for 3 ports connecting 3 servers with 3 different VLAN ID:

(a) *giga 1/2:* vlan 100 -> vlan 300, allow vlan 300 in the trunk, vlan mapping enable, connecting *to eth0.100@…*

(b) *giga 2/1:* vlan 200 -> vlan 300, allow vlan 300 in the trunk, vlan mapping enable, connection to *eth0.200@…*

(c) *giga 2/13*: allow vlan 300 in the trunk , connection to *eth0.300@…*

interface GigabitEthernet1/2 
 switchport
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan 300,700,865
 switchport mode trunk
 switchport vlan mapping enable
 switchport vlan mapping 100 300
 no ip address
 logging event link-status
end

interface GigabitEthernet2/1
 switchport
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan 200,300
 switchport mode trunk
 switchport vlan mapping enable
 switchport vlan mapping 200 300
 no ip address
end

interface GigabitEthernet2/13
 switchport
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan 300
 switchport mode trunk
 no ip address
end