  In the current Internet, there is no clean way for affected parties to react
to poor forwarding performance: when a domain violates its Service Level
Agreement (SLA) with a contractual partner, the partner must resort to ad-hoc
probing-based monitoring to determine the existence and extent of the
violation. Instead, we propose a new, systematic approach to the problem of
forwarding-performance verification. Our mechanism relies on voluntary
reporting, allowing each domain to disclose its loss and delay performance to
its neighbors; it does not disclose any information regarding the participating
domains' topology or routing policies beyond what is already publicly
available. Most importantly, it enables verifiable performance measurements,
i.e., domains cannot abuse it to significantly exaggerate their performance.
Finally, our mechanism is tunable, allowing each participating domain to
determine how many resources to devote to it independently (i.e., without any
inter-domain coordination), exposing a controllable trade-off between
performance-verification quality and resource consumption. Our mechanism comes
at the cost of deploying modest functionality at the participating domains'
border routers; we show that it requires reasonable processing and memory
resources within modern network capabilities.
