  Monitoring streams of packets at 100~Gb/s and beyond requires using compact
and efficient hashing-techniques like HyperLogLog (HLL) or Count-Min Sketch
(CMS). In this work, we evaluate the uses and applications of Count-Min Sketch
for Metro Networks employing P4-based packet-optical nodes. We provide
dimensioning rules for CMS at 100~Gb/s and 400~Gb/s and evaluate its
performance in a real implementation testbed.
