[j-nsp] MPLSoMPLS - horrible?

[Dale Shaw]

Hi Alexandre,

On Thu, Sep 30, 2010 at 7:17 PM, Alexandre Snarskii <snar at snar.spb.ru> wrote:
>
> Right question would be 'How do you exchange labels with your NSP?'.
> Because if there are no such exchange your NSP will not know what to
> do with MPLS packet entering his network and will just drop it at
> ingress.
>
>> Is it too horrible to even contemplate?
>
> It's hardly possible without setting CsC with your NSP.

Right. Yes, I hadn't appreciated that the carrier's PE would need to
handle labelled packets. It seems obvious now :-)

> With L3VPN all you have is IP[v6] connectivity between your CE routers,
> so the only way to run MPLS without NSP support is to run GRE tunnels
> between your CE's and then run MPLS over these GRE tunnels. And, yes,
> it is horrible: ethernet frame passing your pseudowire will become
> ethernet over MPLS over GRE over IP over MPLS over ethernet with terrific
> overhead and lots of MTU issues :)

OK, yeah. It sounds .. sub-optimal .. but now that I have some more
key words / concepts to search for, I'm getting the impression it's
not an uncommon configuration, especially as it seems J does not
support L2TPv3.

Cheers,
Dale