Cable modem errors

What can cause high cable modem errors,( both corrected and uncorrected) within a short period of time. The drop line is new and appears to be properly buried. The event log states OFDM issues codes 16/24 multiple times, before anyone jumps to any conclusions, the usual culprits have been previously investigated and addressed. My troubleshooting is leaning to Xfinity equipment within the plant area…any constructive ideas or possible solutions would be appreciated and just to add to this the cable modem is a Netgear CM2500 with the Gigabit internet plan. My apologies if the tone seems less than pleasant but this is getting old. Thank you for the time.

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BruceW

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26.7K Messages

3 days ago

... Netgear CM2500 with the Gigabit internet ...

The CM2500 is not compatible with Gigabit internet service. Comcast/Xfinity rates it for wired download speeds "Up to 936 Mbps". Follow the "See all modems" link near the bottom of https://www.xfinity.com/support/internet/customerowned, Then under the "Compatible modems for enhanced speeds" or "All compatible modems by brand" heading click the Netgear list. Using devices on Internet speed tiers for which they are not approved tends to produce unexpected results, often speeds well below the ones you are paying for.

AFAIK Comcast/Xfinity has never said how they provision devices operating on speed tiers they're not approved for. All I can tell you is that many customers who tried it have reported that they don't get full speed. There's a tendency to think the device will operate at the maximum speed it is capable of, but that doesn't seem to be the case.

You need to either get a device compatible with Gigabit, or drop back to a plan speed for which the 2500 is compatible.

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user_xxlt6b

7 Messages

@BruceW The issue was not actually speed related as I am aware that the CM2500 isn’t rated for Gigabit, the problem is excessive errors ( uncorrectable) and the ODFM codes16 / 24. With a new buried drop installed, in a conduit no less, I would think that there should be all zero,s in both the columns. I believe there could be equipment ( Xfinity) issues somewhere within the plant in this area, considering how much I invest in Xfinity , I think things should be good,,,,however such is not the case. Would it be that big an issue to have it looked into.

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3 days ago

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user_xxlt6b

7 Messages

3 days ago

I thought I would mention the CM2500 is on the 500 Megabit plan, so plan speeds are not a problem.

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XfinityDilary

Official Employee

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2.6K Messages

2 days ago

Thanks for posting on our Community Forums, user_xxlt6b. I'm sorry to hear about the modem errors you've been experiencing. I know it can be frustrating, and we'd like to help get this resolved once and for all. What troubleshooting steps have you taken so far?

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user_xxlt6b

7 Messages

I have inspected all the coax cable connections , factory reset my cable modem, I am using only 2 Antronix 2 way splitters,,,one under my house feeding the main bed room tv box and the other to the second splitter to my cable modem and the other end to the cable box. The down stream signal levels are well within the 3 dB of each other ,the upstream shows all 5 channels within 1 dB. The signal quality shows approximately 42.5 to 42.9 for all the downstream channels. ODFM has the normal high correctables but the uncorrectables is quite high where it should be zero. This all combines to have very high error rates (multiple thousands) in most of the downstream channels. I believe something is not quite right…

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1 day ago

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XfinityThomasA

Official Employee

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2.7K Messages

Thank you for performing those troubleshooting checks, user_xxlt6b. Let's dig a bit deeper and troubleshoot this issue together. If you could please send a direct chat message with your full name and complete service address to “Xfinity Support”, I'd be happy to look into this with you. To do so, click on the chat icon located at the top right of this forum's page.

Here are the detailed steps to direct message us:

• Click "Sign In" if necessary

• Click the "Direct Message” icon (upper right corner of this page)

• Click the "New message" (pencil and paper) icon

• Type "Xfinity Support" in the to line and select "Xfinity Support" from the drop-down list

• Type your message in the text area near the bottom of the window

• Press Enter to send your message

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1 day ago

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user_xxlt6b

Cable modem errors

BruceW

Please be aware that there are 2 kinds of responses in this Forum: Replies and Comments. When you Comment on a post by scrolling down to "Comment on this post here...", I am notified of your response. But if you select Reply, I am NOT notified and may not be aware of your response.

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