Per-hop Interface-id

Per-hop Latency and Load


Goldman Sachs's Technology Fellow and Network Architect Mike Valentine present Path Tracing at NANOG85

Ahmed Abdelsalam of Cisco demonstrates Path Tracing: Revealing the Unknowns about ECMP

Detect blackholes

Path Tracing is capable of reporting if any paths in the network are blackholing trafic.

Detect corruptions

Path Tracing detects if there’s any unexpected forwarding path that doesn’t match the control plane.

Detect ECMP paths with incoherent latency

Measure the latency of each ECMP path in your network and report any path with a non-coherent latency with respect to the others.

Measure jitter on a per-interface/queue basis

Path Tracing delivers, for the first time in history, accurate jitter measurements in the live WAN!

Identify the trajectory and time taken for NFV processing

Path Tracing reports the trajectory (proof of transit) and the time taken overall to execute that service chain.

Path Tracing Tutorial and Demo

Path Tracing allows operators to deterministically monitor ECMP paths. It is implemented in HW at linerate, in the normal forwarding pipeline to report accurate data. Path Tracing is coupled with an SDN analytical app that analyzes the Path Tracing data, correlates it with routing information, and computes key metrics for operators to monitor the health of their network.


Path Tracing is being standardized by the IETF.

Open-source softwares supporting Path Tracing