Preparations for the SC22 demo.

Succesfully tested flow and packet marking with XRootD 5.5.0 and the latest version of Flowd. Packet marking was performed by flowd via eBPF-TC (so external process was marking packets for xrootd). Verified that flow label is set in all packets (so both experiment and activity can be retrieved per packet). 

Flowd can now expose all netlink related infromation (per flow) via Prometheus client (statistics related to TCP/IP, e.g. retransmits, retransmits timeout, RTT stats, PMTU/MSS observed , pacing/delivery rate, congestion window, bytes sent/acked/received, segs in/out, TCP options, congestion algorithm, RCV queue size, time w/o outstanding data, etc.)

We plan to also use CERN P4 setup to collect flow label statistics directly on the network equipment (to showcase possible implementation for the R&E networks).

Meeting notes: flowd works out of box with recent version of XRootD, deployment activities in the UK and plan to extend that to the US after SC22. Still too early for massive deployment that should aim for DC24, documentation comes later and currently involved only active participants RNTWG.