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Very slow upload speed on HFC NBN 100/40 plan

I'm in Thornleigh, NSW area and recently I got constant very slow upload speed on HFC NBN 100/40 plan. now only around 2-3Mbps. I tested many times in different time. Even in off peak time, I still got the same result. 


As a professional network engineer for more than 10 years, I have checked my home network, router and other devices and can be sure that it is not an issue in my home devices. It is definitely a throttle on Optus side. 


Tried to contact Optus, but the response is way too slow and after waited hours, the message I got just suggest me to reboot he router/modem. That really sounds like a suggestion from a non-technical person.


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Honoured Contributor
Honoured Contributor

Re: Very slow upload speed on HFC NBN 100/40 plan

Hi, I'm an engineer too (although not a professional one). Unfortunately the upload speeds you are seeing is likely the result of congestion and of the technological choices the nation made in installing the NBN. What it isn't is Optus throttling and checks will show that the NBN is working as expected.

So a mix of various things:

1) The HFC technology has a weakness for handling uploads.

2) NBNCo has been prioritising bandwidth for downloads. So there is a very small allocation of upload bandwidth for a given area. If more than a couple of houses near you are trying to upload anything then it will overload that allowance and upload speeds crash for all.

3) There's usually no RSP promises on upload speeds (Optus is required to provide around 80Mbps download speeds most of the time, but there's no such promise that uploads will be the same)

Obviously a lot of people are now uploading from home and while FTTP would have handled all this with ease, HFC doesn't. For the time being there is likely nothing you can do as far as Optus and NBNCo are concerned the system is working as well as it can.