[ ] Metric: JVM socket handles per neighbor. How these handles scale with the amount of nodes.
[ ] Metric: Initial Sync throughput with "0" latency. Sync throughput with solid latest milestones (COO unchanged) or transfer all the Txs (with changed COO address).
[ ] Metric: How long a transaction takes to travel a Neighbor chain. TCP vs UDP. Peer latency: two nodes, network latency: chain nodes.
[ ] Metric: UDP processed / dropped ratio. Processed means executed by the ExecutorService processor. Processed transaction vs broadcasted.
[ ] Metric: Network spent CPU time vs all the rest.
[ ] Metric: Amount of packets discarded at OS level / IRI.
[ ] Metric: Txs Broadcast queue vs network-transferred Txs.
if you have to evaluate metrics libraries take a look at micrometer, too. I tried it out recently and it is very easy to work with. http://micrometer.io/