On 1/18/22 16:28, Saku Ytti wrote:
2) MPLS-TTL expires in transit 2a) generate TTL exceeded and put it back to tunnel, sending it to egressPE, which is guaranteed to know how to return to sender
This is what we run - our core is BGP-free (LDP), so the traceroute value customers see will be the egress PE router.
2nd best is to tunnel, but the RTT will confuse uneducated, or as it may be, hjghly educated, users.
It is very confusing, even for some educated users. It's become less of problem, as years of educating users seems to have bedded in.
We could implement something like https://ytti.github.io/icmp-eo-timestamp/draft-ytti-intarea-icmp-eo-timestam... to offer correct forward latencies to P/LSR in 2a scenario.
I recall you and I chatted about this some 3 or so years ago. Do you know if anyone of the (un)usual suspects have implemented? Mark.