[j-nsp] local switching l2circuit not passing traffic

[sthaug at nethelp.no]

> > I have what I thought was a pretty simple config - Two VLANs on two GigE 
> > interfaces, on a MX240 running 9.4R2.9 which are cross-connected within 
> > the MX using a l2circuit.
> > 
> > If I remove the 'vlan-ccc' encap from the units and assign an IP, we can 
> > ping to something on the other end - So at least we know end-to-end 
> > works on both interfaces. Once it's reassembled as a l2circuit, there is 
> > no connectivity between the two end points. I'm sure it's something 
> > pretty elementary, but I can't determine what it is. Is there a way to 
> > sniff or capture traffic on the l2circuit to see what is going on?
> > 
> 
> The VLAN numbers at both ends of the l2circuit need to be the same for 
> it to work.
> 
> This is a very poorly documented limitation of the l2circuit feature.

With MX you have ample possibilities to push/pop/rewrite VLAN tags, so
VLAN IDs at each end do *not* need to match given a suitable rewrite.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no