About 2 weeks ago, I noticed that my computer was always humming. Turned out that DropBox was stuck trying to upload some files. The files in question still haven't uploaded.
The long and the short of it is this: I have some good ideas about what's going on but have so far been unable to get Verizon to let me communicate with someone who has hopes of having of understanding what I'd like to communicate. I probably need to talk with a L2 or L3 tech, but haven't figured out how to accomplish that, and Verizon can't seem to figure out how to fix the problem.
The problem:
- Uploads of tiny files (< 100 bytes) are likely to succeed.
- Uploads of files in the 20KB range succeed sometimes.
- As the file size approaches 1MB, the probability of success approaches 0.
- Doesn't matter how the device is connected to the router, or what site you're trying to upload to--Google Drive, DropBox, Yahoo Mail, Verizon Mail, etc.
- Our Android phones experience this when on the WiFi network, but work seamlessly when on the T-Mobile network--part of the proof that this is a Verizon network problem.
- There is a growing list of neighbors who also have FiOS Internet (some with as much as 75/35 speeds) and are experiencing the same problem. Speed tests show that the upload (and download) speeds are close to what is expected, but uploads just don't work.
- Downloads work fine, and ping/traceroute tests look good. WinMTR shows no problems whatsoever.
- But when I used wireshark to capture the packets while attempting to upload an attachment to mail.verizon.com, I could see what was happening. The TCP connection got established, but the server was sending lots of duplicate ACKs. This got out of hand as time progressed, and eventually the TCP stack on my computer gave up and shutdown the connection. It is quite likely that one of 2 things is happening. (1) Outbound packets are being corrupted and so being dropped at the receiver--the verizon mail server in this case--when the checksum fails in the TCP/IP stack. Uploads of larger files use larger packet sizes and the probability of corruption is increasing with packet size. (2) Outbound packets are being lost/dropped in the Verizon network for some reason, which again is happens with higher probability during larger uploads.
I've noticed other posts which sound similar but which do not describe how the problem was resolved:
I've probably wasted 3 to 4 hours on the phone with Verizon, as well as 5 hours at my home watching over a technician who readily admitted he hadn't a clue and failed in his effort to get connected with a network tech who was knowledgeable enough to help. The router and ONT were changed in my house. The PON card in the OLT was reset, etc. Of course, none of this helped. Who knows what other tinkering they've done. I can only say that uploads still fail just the same and now downloads seem a bit more sluggish.
Any ideas?
