Dynamic range window violation

Dynamic Range Window violations won't directly cause uncorrectable errors on your channels, but an overall problem might cause both DRW violations and uncorrectable errors. Uncorrectable errors are a downstream data transmission issue.

A dynamic range window violation is an upstream problem that happens when your modem sends a ranging request and then gets back a power level request for a channel is more than 12 dBmV above the lowest power level in the upstream channel set.

Basically, at least 2 times per minute, your modem asks the Cox system "how loudly should I transmit on each channel?" If Cox comes back with numbers like 45, 44, 43, 41 then that's all good. But if it comes back and asks for numbers like 38, 36, 52, 39 that would be a dynamic range window violation because the highest value (52) is more than 12 above the lowest value (36).

I've tried to get someone to give me more information but so far I've had to learn all of this on my own while trying to troubleshoot my own problems. I don't know how bad a DRW violation is overall but it does seem like upstream data like video calls will glitch momentarily when a DRW violation happens. I think the DRW violation itself is probably caused by a momentary spike of noise on one of the upstream channels. Like I said I don't know this for sure but this makes sense based on what I've been learning.

When my connection was working well I would get two or three DRW violations per week at most. Then when my connection started to go bad, I was getting up to 40 DRW violations per hour. Now I'm getting T3 timeouts which is a more serious type of upstream issue that causes a complete interruption of data for a short time.

No one has been able to provide any real information about how serious DRW violations are, but I think of them as an early warning of problems that are going to get worse later.

I'll also say that two of your channels are at the highest recommended power level for 4 bonded channels (51 dBmv). Even though that's technically within spec, it leaves no room for error. Any little thing is going to send the power level above the recommended range. It's hard to get techs to understand that because they only look at the raw number, but that high of an upstream power seems like a developing problem. Some techs will also quote the highest power for a single channel which is 61 dBmV but if you're only using one channel you aren't getting your full upload speed so for the real modern world 51 dBmV is the maximum.

@Peterrockinit, The modem was recently reset about 5 hours ago and I am not seeing any errors now. Are you currently experiencing any issues with the internet service? -Allan, Cox Support Forums Moderator