said by xShades :
Shaw runs a network that it sells to its customers.
If that network is in part or fully overloaded in that it causes high latency high jitter communications it will have 2 effects.
1. A huge increase in support calls. Support calls cost money.
2. People will leave and try another service.
I'm giving Shaw the opportunity to retain my business by fixing my issue. If they wont or cant then I move on, no big deal.
In my instance I believe its just some EMI or mis-configured modem that's causing the random jitter. My bandwidth is fine, if it was an over loaded core router I would expect to see a reduction of bandwidth along with the jitter, that is not the case.
DOCSIS 3 modems up-channels are notoriously difficult to tune for a clean signal. I'm hoping the tech that comes today can clean up mine and get rid of this nasty jitter.
I still think you should look into bufferbloat as it sounds a lot like your situation with uploading and jitter/ping time.
Today's Security Now episode (twit.tv) had a Q&A section covering this exact scenario.
Have you tried testing it with your modem/router in bridged mode and directly connected?