xFi Complete Increased Upload Speeds - NOT

@XfinityShan​ 

After a DM, 3 tech visits, 2 calls to the Denver dispatch center, 4 visits to the local Xfinity store, working with a tech on my next door neighbor's new install that is getting the faster upload speeds, a maintenance investigation and a call to the loyalty department, it looks like my problem is that I need to be moved to the Gigabit X2 plan (I'm currently on the Gigabit Extra plan).  However, my address does not even show the Gigabit X2 plan because I don't have a Sales Area Code entered into the system for my address.  My next door neighbor has a sales area code of 422 so that's what code I should have (instead of no code at all).  The Loyalty team that uncovered this, had the local store order a tech visit to determine my Sales Area Code and update the system.  However, the tech and his manager have never heard of a sales area code and certainly couldn't update it since they don't even know what it is? 

Any chance someone here could fix this? 

Someone locally was able to fix the sales area code and they signed me up for the X2 plan.  After a reprovision and a reboot, I now get fast upload speeds.  However, the download speeds have taken a hit (average half of what they should be) so I have a technician coming out to see why that is.

Hey again @user_58a5ea, thanks for reaching back out and updating us! I'm glad they were able to get the code updated for you and got a tech sent out. We appreciate all your time and help getting it fixed! We'll check in with you after your appointment to make sure everything is working well.

Hi there, @user_58a5ea I hope you are having a wonderful day! I'm just following up with you to see how your service is working?

Sorry for the delayed response.  I now have faster upload speeds but it resulted in new problems that I have been trying to resolve (including another tech visit) but have hit another dead end.

I was on the Gigabit Extra plan and used to get 1.4 Gbps down and 35-40 Mbps up, very consistently.  Like clockwork, with little to no fluctuation.  To get the faster upload speeds, I had to (happily) switch to the Gigabit X2 plan.  This plan claims 2 Gbps down and 200 Mbps up. 

I’m using the speedtest.xfinity.com web site to test my speeds.  My upload speed never goes near the advertised 200 Mbps.  It usually gets 90-110 Mbps.  My download speed fluctuates wildly.  It never finishes near the advertised 2 Gbps.  It often finishes the test around 1.0 - 1.2 Gbps but sometimes goes as low as 400 Mbps and as high as 1.8 Gbps (very rarely). 

So, it seems to me that there are potentially two different issues going on.  Something is blocking me from getting the full 200 Mbps upload (only get half that).  And something isn’t handling the 2 Gbps download very well (typically get half that with wild fluctuations). 

I first turned to my own network in case my network was crapping on the 2 Gbps download.  I have a home office where my one and only Xfinity coax connection comes directly into the XB8 cable modem.  From the 2.5 Gbps ethernet port on the modem I go into a 2.5 Gbps 8-port ethernet switch.  Each of my two computers has its own 2.5 Gbps ethernet adapter and they are running Windows 10.  I’m using all cat-6 ethernet cables. 

To test my local network, I installed iperf3 on both of my computers and I get 2.5 Gbps transfers between my two computers, in both directions, with no problems.  So it appears the problem is somewhere upstream from the modem ethernet port.  I tried direct connecting the modem 2.5 Gbps ethernet port to one of my computers with no change.  I tried swapping the ethernet cable (from one of my computers and the 2.5 Gbps switch) with the cable modem ethernet cable (from the cable modem to the 2.5 Gbps switch) with no change.

An Xfinity tech came out and the Ethernet port on his test set was limited to 1 Gbps so that test didn’t reveal anything interesting to him or me.  He used his test set to measure the coax cable speed (the coax cable that connects to the modem) and, while he measured 2 Gbps down on the cable, he saw a very large and unexpected dropout.  He called support and they told him to update the firmware on his test set.  He did that and then ran the test a few times and measured 2 Gbps down with 248 Mbps up (no dropouts).  He called the maintenance crew and they confirmed that the network was updated to support the 2 Gb / 200 Mb plan.  I showed him my iperf3 results indicating my office network was capable of supporting 2.4 Gbps.  He reprovisioned the XB8 modem and even swapped the modem out.  He said my signals at the tap and at my modem looked great, but he ordered a new drop because he didn’t know what else to try.  My RG-11 drop was pulled through an existing conduit 3 years ago so I don’t see how that will help anything, especially since my signals all look great. 

He was never able to demonstrate 2 Gb / 200 Mb out of the modem ethernet port so my concern is that there’s a missing firmware update or configuration setting, etc. that is causing my modem to not behave.  The fact that it never delivers more than half the advertised 200 Mb upload speed (while the line shows 248 Mbps) is a red flag for me.  What is the next step to resolving this issue?