Do you care about "gray" failures? Can we (network academics) help? A 10-min survey

Saku Ytti saku at
Thu Jul 8 12:29:38 UTC 2021

On Thu, 8 Jul 2021 at 15:00, Vanbever Laurent <lvanbever at> wrote:

> Detecting whole-link and node failures is relatively easy nowadays (e.g., using BFD). But what about detecting gray failures that only affect a *subset* of the traffic, e.g. a router randomly dropping 0.1% of the packets? Does your network often experience these gray failures? Are they problematic? Do you care? And can we (network researchers) do anything about it?”

Network experiences gray failures all the time, and I almost never
care, unless a customer does. If there is a network which does not
experience these, then it's likely due to lack of visibility rather
than issues not existing.

Fixing these can take months of working with vendors and attempts to
remedy will usually cause planned or unplanned outages. So it rarely
makes sense to try to fix as they usually impact a trivial amount of

Networks also routinely mangle packets in-memory which are not visible
to FCS check.


More information about the NANOG mailing list