Hi there

I tried to configure the system mtu to 1998 and the routing mtu to 1998, but still it wouldnt come up.

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You wont be needing the routing MTU just to pass QinQ frames. Try the mtu system jumbo command: http://www.cisco.com/en/US/products/hw/switches/ps700/products_configuration_example09186a008010edab.shtml#c4a

Can you pastebin the configurations? Maybe there's something else other than MTU that's in the way. Generally this should work.

the setup is like this SW1<>SW2<>SW3. SW1 and SW3 are the ones terminating the QinQ tunnels. SW2 is just forwardingn the QinQ vlan

configs for SW1 - Huawei CX 300A

interface Ethernet2/0/4

description XXX

port link-type dot1q-tunnel

port default vlan 106

trust 8021p

qos queue be cir 80 pir 90

qos queue af1 cir 80 pir 90

qos queue af2 cir 80 pir 90

qos queue af3 cir 80 pir 90

qos queue af4 cir 80 pir 90

qos queue ef cir 90 pir 100

qos queue cs6 cir 80 pir 90

qos queue cs7 cir 80 pir 90

interface Ethernet2/0/5

description to-cisco-2960

port link-type trunk

port trunk allow-pass vlan 106

trust 8021p

qos queue be cir 80 pir 90

qos queue af1 cir 80 pir 90

qos queue af2 cir 80 pir 90

qos queue af3 cir 80 pir 90

qos queue af4 cir 80 pir 90

qos queue ef cir 90 pir 100

qos queue cs6 cir 80 pir 90

qos queue cs7 cir 80 pir 90

##########################################################

SW2 configs - cisco 2960

SSC_2960#sh system mtu

System MTU size is 1998 bytes

System Jumbo MTU size is 9000 bytes

Routing MTU size is 1998 bytes

interface FastEthernet0/4

description QinQ_Vlan_to_huawei-CX-300A-Ethernet2/0/5

switchport trunk allowed vlan 106

switchport mode trunk

interface FastEthernet0/6

description QinQ_Vlan_to_huawei-CX-300A-Ethernet3/0/7

switchport trunk allowed vlan 106

switchport mode trunk

#####################################################################

SW3 configs - Huawei CX300A

interface Ethernet1/0/10

description XXX

port link-type dot1q-tunnel

port default vlan 106

trust 8021p

qos queue be cir 80 pir 90

qos queue af1 cir 80 pir 90

qos queue af2 cir 80 pir 90

qos queue af3 cir 80 pir 90

qos queue af4 cir 80 pir 90

qos queue ef cir 90 pir 100

qos queue cs6 cir 80 pir 90

qos queue cs7 cir 80 pir 90

interface Ethernet3/0/7

description to-cisco-2960

port link-type trunk

port trunk allow-pass vlan 106

trust 8021p

qos queue be cir 80 pir 90

qos queue af1 cir 80 pir 90

qos queue af2 cir 80 pir 90

qos queue af3 cir 80 pir 90

qos queue af4 cir 80 pir 90

qos queue ef cir 90 pir 100

qos queue cs6 cir 80 pir 90

qos queue cs7 cir 80 pir 90

Looks fairly straight forward. What exactly isnt working? Do you see mac addresses in the 2960 and in the remote Huawei?

can you span fa0/4 and fa0/6 on the cat2960 (making sure you capture vlan tags) while you ping end to end from your laptops?  so we can sure that the double tag imposed by huaweii switch is compliant with specs.

Riccardo