On Monday, July 12, 2021 9:46am, "Livingood, Jason" 
<jason_living...@comcast.com> said:

> I think latency/delay is becoming seen to be as important certainly, if not a 
> more direct proxy for end user QoE. This is all still evolving and I have to 
> say is a super interesting & fun thing to work on. :-)
 
If I could manage to sell one idea to the management hierarchy of 
communications industry CEOs (operators, vendors, ...) it is this one:

"It's the end-to-end latency, stupid!"

And I mean, by end-to-end, latency to complete a task at a relevant layer of 
abstraction.

At the link level, it's packet send to packet receive completion.

But at the transport level including retransmission buffers, it's datagram (or 
message) origination until the acknowledgement arrives for that message being 
delivered after whatever number of retransmissions, freeing the retransmission 
buffer.

At the WWW level, it's mouse click to display update corresponding to 
completion of the request.

What should be noted is that lower level latencies don't directly predict the 
magnitude of higher-level latencies. But longer lower level latencies almost 
always amplfify higher level latencies. Often non-linearly.

Throughput is very, very weakly related to these latencies, in contrast.

The amplification process has to do with the presence of queueing. Queueing is 
ALWAYS bad for latency, and throughput only helps if it is in exactly the right 
place (the so-called input queue of the bottleneck process, which is often a 
link, but not always).

Can we get that slogan into Harvard Business Review? Can we get it taught in 
Managerial Accounting at HBS? (which does address logistics/supply chain 
queueing).
 
 
 
 
 

_______________________________________________
Bloat mailing list
Bloat@lists.bufferbloat.net
https://lists.bufferbloat.net/listinfo/bloat

Reply via email to