[j-nsp] l2circuit between ASR9k and MX80

[Saku Ytti]

On (2015-07-31 12:41 +0200), Marcin Kurek wrote:

Hey Marcin,

> I wanted to ask about a particular piece of config.
> I would expect that it shouldn't work, but it works perfectly, so I'm a bit
> confused.

I'm answering for 7600/ES+ perspective (which is same as original ASR9k
linecard).
I too had similar situation and was confused why it works.

> interface TenGigE0/0/1/5.3101 l2transport
>  encapsulation dot1q 3101
>  rewrite ingress tag pop 1 symmetric

>  ge-1/0/1 {
>         description "ESXi 2 VMNIC3";
>         flexible-vlan-tagging;
>         encapsulation flexible-ethernet-services;
>         unit 3101 {
>             encapsulation vlan-ccc;
>             vlan-id 3101;

So what happens here is Cisco somehow dynamically determines what is required.
In 7600 with this config 3101 _Will be popped_ and _internal VLAN_ will be
pushed, before sending it out to MPLS network.
But as it works with you, it is probably pushing 3101 again.
Magically same config in Cisco works against untagged and tagged EoMPLS. Sadly
it's not even possible to explictly/self-documenting configure it 'correctly',
as what you'd want to configure is:

I would recommend adding to junos config output-vlan-map swap, so you can deal
with different SVLAN in each end.

-- 
  ++ytti