Cisco 7600: How to extract inner vlans from q-in-q vlan?

Unanswered Question
Sep 21st, 2009

Hello.


I've got a 10GE trunk interface from our partner. One vlan (id 1149) that comes on this port is a q-in-q vlan carring four inner vlans. How can I extract them?


Current interface configuration:


interface TenGigabitEthernet3/4

description XXXXXXX

switchport

switchport trunk encapsulation dot1q

switchport trunk allowed vlan 1140-1150

switchport mode trunk




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rducombl Mon, 09/21/2009 - 23:47

Hi,


I am not sure I understand exactly.

But if you are receiving double tag traffic with 1149 as outer dot1q and let's say vlan x,y and z as inner vlan.


You need to select one output port to which you will send the traffic.


If this port is on a regular lan line card (any Ws-X67xx) for example you can configure that port as Dot1q tunnel port :

interface gig 1/1

description XXXXXXX

switchport

switchport mode dot1q-tunnel

switchport mode access vlan 1049


--> with that config we will remove vlan 1049 from each packet incoming on the ten gig int with vlan 1049 and sends only the inner vlan out on gig 1/1 for example.

config guide for dot1q tunneling is at : http://www.cisco.com/en/US/partner/docs/routers/7600/ios/12.2SR/configuration/guide/dot1qtnl.html





If your egress line card would be an Es-20, Es+ or sip-400, you may do the same with EVC config using service instances. Some info on service instance can be found in :

http://www.cisco.com/en/US/partner/docs/routers/7600/install_config/ES40_config_guide/es40_chap4.html



Roland

osenevp Tue, 09/22/2009 - 02:14

Hi Roland,


Yes vlan 1149 used as outer dot1q and vlan 143,156,841 as inner vlan.


In my setup there's no ES20 card, so I have to follow your sugesstion with the output port. Thanks for configuration example!


Is there any possiblity to remove the outer dot1q vlan on 7600's SVI?

rducombl Tue, 09/22/2009 - 05:36


hi,


No on SVI on 7600 you cannot do that.

Actually you cannot even route a double tagged packet on an SVI.

if you only have LAN line card I fear you are limited to the dot1q tunnel access port.


Roladn

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