Vlan translation and Swapping

[Asemmoqbel]

Heey, all

As an ISP provider, We are trying to connect Multiple customer sites via our Mpls core.

our plan to give each customer site a different vlan ( c-vlan) and then translated to S-vlan to transport the frames through our network. we know about vlan map as we map each customer vlan to s-vlan but this is Symmetrica operation which I read on cisco article

(On an interface configured for VLAN mapping, the specified C-VLAN packets are mapped to the specified S-VLAN when they enter the port. Symmetrical mapping back to the customer C-VLAN occurs when packets exit the port.)

But this won't work in our design because we want to assign a different vlan at each customer site. 

I read on junpier articles they have a technology vlan swapping which swap c-vlan with new s-vlan by discarding the c-vlan tag and adding a new s-vlan tag.

This is written in juniper article:

(VLAN translation (swapping) replaces an incoming C-VLAN tag with an S-VLAN tag instead of adding an additional tag. The C-VLAN tag is therefore lost,)

Is there any similar technology in cisco?

Thanks

[Francesco Molino]

Hi 

Before talking about configurations, did you tried with EVC (service instance configuration)?

[Asemmoqbel]

Hi,

To be clear on our needs in here, I attach a design explains how we want our design.

I read about EVC but I couldn't have solid understanding to apply in my design. if it will meet my requirment Can you please explain it to me.

I will be very thankful.

[Francesco Molino · Accepted solution]

Hi

On your PE1, the config should looks like:

interface g0/1

 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan none
 switchport mode trunk
 service instance 1 ethernet
   encapsulation dot1q 2150
   rewrite ingress tag pop 1 symmetric

   xconnect x.x.x.x 1 encapsulation mpls

On PE2, it will be:

interface g0/1

 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan none
 switchport mode trunk
 service instance 1 ethernet
   encapsulation dot1q 123
   rewrite ingress tag pop 1 symmetric

   xconnect x.x.x.x 1 encapsulation mpls

The frame arrives to your PE1 tagged and when sending out through xconnect, the tag will be removed. A new tag will be added on PE2 with the vlan configured under the service instance. This behaviour of tag removing is done by rewrite ingress tag pop 1 symmetric

Does that help?

I'm sorry, I was planning to connect on 1 of my routers to make some wireshark and show the different frames but didn't had time for that.

Thanks

[Asemmoqbel]

It really seems to work in this kind of logic. I wish I could practice this lab on simulator but no hope since this commands are not avaiable inn GNS3.

Thanks,,

[Francesco Molino]

Hi,

Yeah it will works for sure and this is quite simple and standard design for ISPs.
With GNS3, it won't work, perhaps with IOU images you can have a try but not sure.
Maybe with Virl it will works.