Lost MDD Timeout

For the past three weeks, my household has been experiencing intermittent internet drops. At first I thought it was due to the maintenance Comcast said they were doing around 12/29 in my area, but the drops persisted after the maintenance was complete.

I called Comcast and set up an appointment for a tech to come out, and he stated that the signal was strong enough and encouraged me to replace my 5 year old cable modem.

I replaced my modem, and the internet drops continued intermittently. Throughout these drops, both modems continued to report "Lost MDD Timeout" events. My family and I are frustrated by the random internet drops.

Comcast, can you please assist with some more in-depth troubleshooting?

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XfinityDuron

Official Employee

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473 Messages

15 days ago

Hello, I hope you're having a great day. I'm reaching out to see if you are still having your internet drop issues at this time?

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user_w8hezw

Visitor

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5 Messages

@XfinityDuron This past week we had one occasion where this occurred. Last week there were two occasions. Each time we got a text message stating that there was a network performance issue that xfinity was working to resolve.

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(edited)

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9 days ago

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XfinityQuemekia

Official Employee

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882 Messages

Are you also experiencing issues outside of the service interruptions @user_w8hezw? I see you mentioned the occurrences that happened recently you received the notification of the service interruption.

Here's also some great internet troubleshooting tips to check out:

https://forums.xfinity.com/conversations/your-home-network/internet-troubleshooting-tips/602dae4ac5375f08cde52ea0

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7 days ago

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user_w8hezw

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@XfinityDuron @XfinityQuemekia I suspect that I'm still having issues even outside of the "service interruptions." I'm still seeing "Lost MDD Timeout" messages in the log file of the cable modem.

In addition, several new messages have popped up, including "SYNC Timing Synchronization failure - Loss of Sync" and "No Ranging Response received - T3 time-out;"

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7 days ago

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XfinityEricB

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3K Messages

user_w8hezw Are those errors you are seeing at random occurances every so often or are they something you see frequently like within the same hour of the day?

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7 days ago

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user_w8hezw

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@XfinityEricB since 1/19/2026, there have been 18 occurrences of "No Ranging Response, at least once per day.

In the same time period, there have been 30 occurrences of "SYNC Timing Synchronization failure".

3 instances of "RNG-RSP CCAP Commanded Power in Excess of 6 dB Below the Value Corresponding to the Top of the DRW;"

4 instances of "TCS Fail on all Upstream Channels"

1 instance of "Missing Mandatory MDD TLV on primary DS Channel;"

(edited)

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7 days ago

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Your Home Network

user_w8hezw

Lost MDD Timeout

XfinityDuron

user_w8hezw

XfinityQuemekia

user_w8hezw

XfinityEricB

user_w8hezw

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