I've spent countless hours troubleshooting our Xfinity Internet, including multiple customer calls and a technician visit. We have the 1000Mbps service with unlimited data.
Here are the symptoms:
I am a software engineer, so it was natural for me to try various setups and process of elimination to see where the problem is. Before I present my findings, a couple of things to note:
Here is a summary of trying different scenarios:
|Modem Used||Modem Used||Modem Used||Modem Used|
|4-way 5-1002MHz splitter, modem downstairs||Occasional packet loss (always)||Extreme packet loss (December)||Not tested||No issues|
|4 way 5-1002MHz splitter, modem upstairs||Occasional packet loss (always)||Not tested||Not tested||No issues|
|4 way 5-2500MHz splitter + MoCA filter, modem upstairs behind MoCA||Severe packet loss and disconnects (February)||Not tested||Severe packet loss (February)||No issues|
|No splitters, modem upstairs||Severe packet loss and disconnects (February)||Not tested||Severe packet loss (February)||No issues|
On the cable configuration:
On the modem used:
Further, here are the signal levels as reported by SB8200 right at the cable coming into the house (yeah, I moved my modem and router down there just to test that.)
OK, next, a few more observations:
Alright, now we can try to logically figure out what's going on here:
So at this point I have several different hypotheses:
If Comcast and I can't work together to fix this issue, I'd have to sadly go back to 100Mbps plan and use an old modem 😞
What do you guys think?
@realyc Hello, and thank you for taking the time to reach out regarding your connection issue. I appreciate all the research and information you provided and I want to help in any way I can, I'd like to get your account pulled up to see what the signals look like on our end.
Please send me a private message and include your first and last so I can assist you. To send me a Private Message, please click my name “ComcastAbbie” and click “Send a message”
You need to get the techs re-involved. There is a severe amount of cable *tilt* with your connection (15 dB). That is the amount of power rolloff / difference between the lowest and the highest downstream channel frequencies. This can not be fixed remotely. It will take * boots on the ground* to fix this.
Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home.
Good luck !
Thanks @EG!! That's a very nice catch!! Do you have any tips on how to escalate properly so I can get someone who is knowledgeable enough to take a look? It would be a waste of time if another technician comes on site, looks at his iPad and tells me all the signals are green 🙂
Quite welcome ! The employee @ComcastAbbie that responded to you can get the ball rolling. Did you send the requested private message? If not, please do so.
Good luck with it !
Thanks @EG. Yeah I have been in contact with the Comcast agent via private message, but it is going rather slowly and a different person responds every time. I'm not giving up hope yet as we're still working through the basics, but yeah, it's slow.
OK, I have some updates. Comcast sent another technician (a very nice guy!) who checked the line at the ground block, two different coax sockets in the house (upstairs and downstairs), and also the tap on the street. If I remember things correctly, his discoveries were:
Note that the tap was very close; there was only one house between the tap and my house, and if I saw correctly, the tap had six connectors plugged in.
Here are some more things we discussed:
Here's what I plan to do:
Also something to note:
@EG What do you think? Does the packet loss difference between the tap and the house (which I estimate to be about 100ft of cable length) seem normal to you? Thanks 🙂