Stupid Question maybe?

Thu Dec 20 18:15:45 UTC 2018

On Thu, 20 Dec 2018 at 20:07, William Allen Simpson
<william.allen.simpson at gmail.com> wrote:

> Then there were the fine vendors that conflated the link and IP headers.
> That fell apart when IEEE started assigning OUIs that began with 0x4xxxxxxx.

There is no way to know in-transit what MPLS carries. Vendors have
implemented heuristics of different complexities to try to guess what
is being carried in effort to enable services like ECMP and netflow.
In hindsight MPLS ethertype probably should tell what it carries
MPLS-IP, MPLS-ETH, MPLS-OTHER.
This is on-going problem with no obvious solution, the ECMP issue can
be largely handled by disabling payload guessing and relying on having
sufficient flow entropy in labels. But the services such as netflow
still need transit guessing.

-- 
  ++ytti