3 ms·
What’s even the point of this spin-bit thing? Of what use is an estimate of my roundtrip-time to intermediaries?
by tzahola 9y ago
What’s even the point of this spin-bit thing? Of what use is an estimate of my roundtrip-time to intermediaries?
- nicky0 9y agoNetwork engineers can use it to monitor network performance.
- IshKebab 9y agoHow though, because surely it includes the time outside the observers network? And if they only want to monitor performance inside their network nothing so them from using an out of band system, or even adding their own timing footers to packets.
- nicky0 9y agoRead this comment: https://news.ycombinator.com/item?id=16696159 https://news.ycombinator.com/item?id=16696159
- erpellan 9y agoWhich they could presumably also do by injecting their own packets, not snooping on everyone else's?
- nicky0 9y agoI don't know, how would you inject packets into an encrypted end to end connection? Passive observation of traffic is a useful network performance monitoring technique.
- mhandley 9y agoKnowing the RTT seen by actual user traffic is useful because, for example, it lets you observe if that traffic is encountering excessive queuing. It's hard to know this by other means; for example you may think you can just ping the end systems, but these days ICMP is often filtered, and even it it wasn't, the test probes may be queued differently due to weighted fair queuing, or even take a different path due to equal-cost-multipath routing. In the end, the only true measure is what the traffic itself experiences. Now, whether it is necessary for operators to know if user traffic is seeing excessive queuing is open to debate. But the fact is they do currently use this as one network health measure.