Troubleshooting slow network speeds (FTTH)

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Thread Starter
Dec 6, 2018

I got my Fiber line installed about 2 months ago. The offer I pay for says 1Gbits/s down and 200Mbits up. Naturally, I've never even gotten close to those speeds. At first, when the guy did his thing, I didn't have an Ethernet cable on hand (despite being a network and IT student...I know, the irony), so I used the router's Wifi. I was averaging 70 Mbits down. At first, I was thinking, 'this seems a bit low'...for fibre of course). I went into lectures the next day and people said, you may need to wait for your line to be properly activated...this seemed plausible, so I waited. The next week I stuck an RJ45 on some CATVE and immediately went to average 500Mbits/s (688Mbits/s record). Now, this is great, but it's still half of what I'm paying for.

However, for the past 2 days, I've been having problems. My Desktop (after coming out of sleep) always has the yellow triangle symbol over the wireless icon (faulty ethernet cable so was back to WiFi). I disconnect and reconnect to find the same problem. I restart the wireless on the router, to find the problem is persisting. Only after 3-5 tries does it work. My phone too has been having trouble connecting to WiFi (Authentification problem).

The original CAT5 cable has since 'developed' a problem and has been changed. The Pc hasn't been having the connection problem out of sleep, but Chrome is very slow to do anything. Youtube loads every other time, social media too. I did a speed test and shocked to find speeds of 50 Mbits/s down and 80Mbits/s UP???

On, under Fiber, I noticed this:

Optical signal strength received -21.28 dBm

Optical signal strength transmitted 2.99 dBm

Anything strange with these numbers? I haven't been a student long enough to know if these are standard or not.

I live in France, so I don't know if anyone is familiar with SFR RED. They are my ISP. Some clients under the same package have complained in the past of being capped at 100 Mbits/s...this was on a 1 Gbit/s offer earlier in the year, and SFR RED might have changed some stuff since, so take that info for what it's worth. The LAN ports are by default caped at 100 Mbits/s...I have since changed them to 1000Mbits/s.

I cannot see what the problem is.

ANY help is GREATLY appreciated.



PS: these are my speed test results since installation:



Mar 26, 2002
It's been a long time since I have worked at an ISP (5 years) but I think the recieved signal is low. Is that SNR or TX?

Do you have more than one computer that you can test to ensure that your computer is not the issue?

Also I noticed that some of your speed difference tends to hit when what I consider peak times so it's possible that the connection is getting saturated when others are online, although that shouldn't happen with fiber.

Industry standards (at least in the US) is anything less than 80% is a problem so your ISP needs to look deeper.

When I did troubleshooting for the ISP, i focused on the CPEs first (customers equipment) then work my way back to the service.. so check with other devices, then replace the modem, then at that point it's the service.
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