Re: [mpls] Last Call: <draft-ietf-mpls-in-udp-04.txt> (Encapsulating MPL

Hi,

On 2014-1-16, at 18:06, joel jaeggli <joelja(_at_)bogus(_dot_)com> wrote:
> These tunnels are stateless
yep. (But they don't have to be.)

>  The endpoints not the encapsulators have visibility into the
> end-to-end loss latency properties of the path.
Yep. But when you tunnel some L2 in UDP, apps that were limited to L2 domains - 
where not reacting to congestion may be OK - can now go over the wider 
Internet, where this is not OK.

I'd be great if those apps would change. But in the meantime, it's the duty of 
the encapsulator - who enables this traffic to break out of an L2 domain and go 
over the wider net - to make sure the traffic it emits conforms to our BCPs.

>  the encapsulator is an intermediate hop, similar to any other router
> in the path.
It's not. For the rest of the network, that encapsulator is indistinguishable 
from any other app that sends UDP traffic.

UDP is a transport-layer protocol, and we have practices how it is to be used 
on the net. If you want to use it for encapsulation, you bind yourself to these 
BCPs.

Look at it the other way: if transport area folks would want to send MPLS 
packets into the network in some problematic way, I'm sure the routing and ops 
folks would not be amused.

Lars

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