Hitron CODA, upload speeds intermittently fluctuating

I talked to another live agent. Received more credit. Thanks. They strongly recommended I schedule another technician appointment. This time with the so called "advanced technical team" because I don't think the "advanced technical team" has visited yet. Fine. I scheduled another technician appointment.

After 3 weeks of using the Xfinity Gateway CGM4981COM XB8 to troubleshoot, I'm going to swap it back with the Hitron CODA. I want to simplify my infrastructure, and it's annoying having to be aware that, when the XB8 is serviced in such a way that disables bridge mode, the XB8 can steer my Xfinity cameras away from the network I want my cameras to be on. The CODA performs slightly better too, for whatever reason.

Here's a summary of the current status. I have two open tickets. A maintenance ticket open for the network team, and a ticket open for the backend team. I have an advanced technician appointment scheduled one week from now. It is my understanding that the network/maintenance team with tier 2 resources have tried to address the issue. I requested details about what the root cause might have been (for my own curiosity, or if I need to take any action), but they do not share detailed information to tier 1 agents or to customers (which I'm fine with). I requested the tickets remain open however. I will test across one work week. If it is stable for one work week, I will cancel my advanced technician appointment, request all my tickets to be closed, and mark my solution here, closing this thread.

Got a message from Xfinity assistant asking me to confirm if my internet service is restored. First of all, thanks. Since the problem is intermittent, I need one work week to test if it is stable. I will report it at the end of the work week if it is. If it is, I will request all my tickets/threads to be closed, and cancel any technician appointment I have scheduled. Otherwise, I will report degradation immediately. Thanks again.

Ran into this today:

* **Today, 9:26 AM**
  * Download: 152 Mbps
  * Upload: 49.8 Mbps
* **Today, 9:28 AM**
  * Download: 357 Mbps
  * Upload: 40.8 Mbps
* **Today, 9:31 AM**
  * Download: 357 Mbps
  * Upload: 16.3 Mbps
* **Today, 9:32 AM**
  * Download: 357 Mbps
  * Upload: 16.5 Mbps
* **Today, 9:33 AM**
  * Download: 356 Mbps
  * Upload: 19.9 Mbps
* **Just now**
  * Download: 361 Mbps
  * Upload: 69.7 Mbps

This is the 8th technician to visit. I said, "A live agent promised they would send an advanced technician. You are that advanced technician". They chuckled and said nothing. They said they could not see anything on their cable meter, which is what I expected. All other technicians have said the same. They said it might be my router. Again, the problem is intermittent. I wired my laptop into my modem when the technician was here. I could not reproduce it. The technician leaves. I run speedtest again on my laptop wired directly into the modem. I got 320/63 and 355/74, which reproduces the service degradation I am seeing now. This proves that the speedtests being executed directly on my router (not a device wirelessly connected to my router), via the TP-Link Deco app, is giving me valid speedtest results. I will continue performing speedtests on the TP-Link Deco app. It is a pain to power cycle my modem, move the ethernet cable to my laptop, and bind my public IPv4 to my laptop's MAC address just to get internet on there in order to do a speedtest.

Saw my upload speed drop to 20 Mbps on the TP-Link Deco app's built-in speedtest. Power cycled the modem. Rewired the ethernet cable to my laptop so that my laptop leases the public IPv4 instead of my Deco router. Ran speedtest.net. Got 312/7 with Comcast, Santa Clara, CA endpoint, and 311/12 with Comcast, San Francisco, CA endpoint. Ran fast.com next. Got 240/14 with Santa Clara (San Jose), CA endpoint. Note that upload speed is at the 10-20 Mbps range. Again, expecting 100 Mbps. Again, it's hours after the technician appointment window that I see this.

The only way that I can think of building a case for this is to use a tool that monitors a wider capture window across multiple days. A technician using a cable meter a few times in one narrow cluster is unlikely to see the intermittent degradation.

Speedtests from earlier:

Getting 360/105 now. Starting confirmation testing now and for the rest of the week. 235-350 download, 80-120 upload (upper 1/3).

I'm going to rework my test criteria.

From what I understand, the reality and expected behavior is that upload speeds can fluctuate with high volatility, probably the full 0-120 Mbps. The CMTS is currently not precise enough to handle congestion in a way that guarantees upload speed has a well defined lower bound under normal operating conditions. It's not well defined or well documented really.

Furthermore, technicians are simply unable to test for intermittency. They don't have tooling that allows them to capture/monitor a wide duration. If I were to go through this again, I would try harder to reschedule my technician appointments in such a way where there's a good chance they'll see the degradation reproduced (provided that, of course, I cannot deterministically reproduce intermittent external network degradation, and I'm often in the middle of work).

For these reasons, instead of testing that upload speed stay within a certain range (for example, +/-20 Mbps surrounding 100 Mbps), I will try to test for the frequency of intermittent upload speed degradation. That is, the more infrequent or short lived upload speed degradation is, the better. I don't really have an exact metric for this, but if I were to schedule a technician appointment right now, it is likely they would not see anything wrong, which is a good sign.

The network/backend/maintenance team definitely stabilized something recently to cause the intermittent degradation to be less frequent though. Thanks.