802.1Q Tunneling (Q-in-Q) Configuration Example

Lessons Discussion
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This topic is to discuss the following lesson:

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Great post mate.

First came across this trying to get a CCIE lab set up. Was very useful for that.

Is this still a tech widely used in service providers ?

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Thanks Richie,

I havenā€™t seen it on a real network before and I doubt that itā€™s still used a lot. A lot of service providers use MPLS which can also transport L2 if you want.

Rene

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Great post.

Thanks

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Great siteā€¦to learn new thingsā€¦

Thanks for sharing your knowledgeā€¦

Take care

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You are welcome.

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excellent post. tx alot.

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You are welcome.

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Nice articleā€¦ thanks so much

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Excellent post! I like the simple flow with which you explained it.
Thank you!

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Glad you like it!

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I have a question.

What if I want to have WAN ports in between the customer sites. I mean, image SW3 is not there and fa0/19 of SW1 and fa0/21 of SW2 are replaced with WAN ports. How do we implement QinQ? Is that possible and accepted?

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You canā€™t do it with Q-in-Q because itā€™s not available on the switches, you could however use something like any transport over MPLS to get your VLANs from one side to the other.

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But I have topology something like this.

Router1 (F1) ------ (F3) Router2 (F8) -------- (F4) Router3 (F3) ---------- (F1) Router4

In above topology,

F1 from Router1 and Router4 are switchports.
F3 from Router2 and Router3 are switchports.
F8 from Router2 and F4 from Router3 are WAN ports.

Configured ā€˜dot1q-tunnelā€™ at F3 of Router2 and Router3.
Configured 'encapsulation dot1q ā€™ at F8 of Router2 and F4 of Router3. (The only difference from your above post. Instead of trunk between Router2 and Router3, I have WAN with encapsulation dot1q config.)

Also I have bridged the F8 and Vlan35 under F3 of Router2 and also F4 and Vlan35 of F3 of Router3.

Ping is failing from Router1 to Router4. This I expect to work. :slight_smile:

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So nobody knows answer for the above question? Even to say it right or wrong!!!

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Rene,
Great article, but you might want to edit this little typo as Fa0/20 is not in your example diagrams:

SW3(config)#interface fastEthernet 0/20  
SW3(config-if)#switchport trunk encapsulation dot1q 
SW3(config-if)#switchport mode trunk

I knew what you meant, though, and again, great article!

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Thanks Matt, I just fixed it :slight_smile:

Rene

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Dear Rene!,

you deserve thanks from me. one of our customer in France ordered EVPL link but due to miss understanding of our project team, they configured MPLS L2 VPN. however, our customer requirement is EVPL which they are sending touble tags and they also want their other end End-user to see the inner tag here in Saudi arabia.
The issue came to me and still working on QnQ. However, after studying your topin, i am more than clear now and i belive i can solve their issue tommorow.

Thank you so much.

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Hi Rene,
In frame, Next to source mac will it be customer vlan tag or isp vlan tag?
Router R1 and Router R2 near customer site is bit confusing , my understanding is router terminates all broadcast traffic. How come traffic for the same vlan goes through router to the other side of customer site ?
Please correct me or point me to some links explain about these metro ethernet concepts in detail.
Thanks,
Srini

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Hi Srini,

I used routers just to have some ā€œcustomerā€ device that could do tagging for me in this example. In a real network, you would use customer switches instead.

The tag on the left side is the tag from the ISP, I should probably have used the same color for the customer tag.

Rene