Is your service assurance really service assurance?? (Part 6)

Seems this post from last week has triggered some really interesting debate – Is your service assurance really service assurance?? (Part 5). It was a post that looked into collecting end-to-end service metrics rather than our traditional method of collecting network device events/metrics and trying to reverse-engineer to form a service-level perspective.

Thought I’d give you an update. I’m thinking along the following lines, but admit that I don’t have it all worked out by any means yet:

  1. We need to concept of span like OpenTelemetry does between microservices (in a way, it’s like nearest-neighbour of where each packet is getting pushed).
    Note that for us a span is on a service-by-service basis between nodes, not just a network link-by-link basis between nodes
  2. We need to be able to measure the real-time metrics of the performance of each span as well as any events/faults impacting them
  3. One challenge (one of probably many) is how to avoid flooding the data/management planes. Possibly a telemetry beacon at each node that’s aggregating performance/events of each packet passed for each service?? But what aggregation-window / cache-size to use? Still too impossibly huge to process except with ridiculously low sampling rates??
  4. By chaining the spans we get a real-time, end-to-end trace of services and the performance (and real-time snapshot of service-by-service resource usage in a packet-switched network)
  5. How to efficiently get the beacon data to a centralised logging/management point? Send beacons via management plane? Send via data plane? Take an approach similar to Netflow / IPFIX-style protocols?
  6. How to store data for a short period (ie for real-time analysis/reporting) as well as for long periods. Due to volumes, we’d have to apply aging policies to the data, but it would still be valuable for the purpose of mid and long-term SLA, network health, optimisation, capacity management, etc

As you can see, there are still so many wide-open questions about the feasibility of the concept. But getting feedback from multiple very clever people who read this blog is definitely helping! Thank you!!

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