We just upgraded our Xfinity internet plan from 75Mbps to 1000Mbps last Thursday. After reactivating our modem, we see a boost on our download speed, but the upload speed is still similar to before, and it seems to be capped at 6Mbps. From the website, the 1000Mbps plan is supposed to have 35Mbps upload speed. And, the modem we are using can support up to 151Mbps upload speed. I was wondering if Xfinity is still in the process of upgrading my internet? Or, this is an issue with the equipment and the cable connection?
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Thanks for the detailed information. I wish Xfinity can put this list in the Xfinity support document that one can found easily.
My modem is Arris SB6183. I know it is running on DOCSIS 3.0 and can only reach like ~400Mbps, not 1Gbps download, but I thought it won't matter for upload speed too much since SB6183 can reach 40Mpbs without problem on other cable providers (from several Amazon reviews and tests). I have also reset my modem. So it looks like Xfinity cap the upload speed on their end.
@louis925 wrote: ... Arris SB6183. ... I thought it won't matter for upload speed too ...
The SB6183 isn't approved for Gigabit service. In order to get the 35 Mbps upload that Gigabit provides, you need to have an approved DOCSIS 3.1 device. See https://www.xfinity.com/support/devices/.
Using devices that are not approved for your speed tier tends to produce unpredictable results.