06-22-2012 02:18 PM
My cable modem (BEFCMU10 ver.3) started loosing connection to CMTS every morning. The pattern is quite predictable: the connection is down when I first check it around 8 AM and powercycling or full reset will not restore it; then between 11 AM - 12 PM the connection comes back. When it comes back, speed tests consistently show about 21 Mbps on download and 4.5 Mbps on upload - normal for my XFINITY Internet Performance level in Northeast Philadelphia, PA.
My cable modem was very stable for several years. I can't imagine that this predictable pattern of downtime has anything to do with either line signal quality or problems with my modem.
A few weeks ago, I got a letter from Comcast saying "that the cable modem you are using to access the Internet is an older device and may not be able to receive the full range of speeds available with XFINITY Internet". I have ordered a new DOCSIS 3.0 certified modem (Motorola SB6121) but have not received it yet.
I wonder if Comcast disrupts service every morning to remind me to upgrade my modem. Any thoughts?
06-22-2012 02:27 PM
What do the modem's signal stats look like ? Get them here; http://192.168.100.1
Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.
06-22-2012 02:38 PM
This is a snapshot taken a minute ago - the connection works fine now, at 2:35 PM.
Acquire Downstream Channel 651000000 Hz Locked
Connectivity State Operational Operational
Boot State OK Operational
Security Enabled BPI+
Lock Status Locked
Channel ID 1
Symbol Rate 536.0537 Ksym/sec
Downstream Power -3.7 dBmV
SNR 34.3 dB
Lock Status Locked
Channel ID 3
Symbol Rate 2560 Ksym/sec
Upstream Power 46.0 dBmV
06-22-2012 02:42 PM - edited 06-22-2012 02:43 PM
O/k At that moment you don't appear to have an RF signal / connection quality issue provided that the stats are remaining stable. SNR is a bit low however. Do they stay within 3-4 dB when things are bad ?
06-22-2012 02:57 PM
I don't think I was able to get to the modem "status" page when connection was down (and the "cable" LED was flashing). If the downtime pattern does not change and the connection is down again tomorrow morning, I'll try again.
When the service was on in the past couple days (in the afternoon), the SNR was between 32 dB and 35 dB. I read somewhere that cable operators adjust downstream power to keep SNR above 30 dB - which seems to be my case.
06-22-2012 03:14 PM - edited 06-22-2012 03:17 PM
Some makes and models of modems do need to be in "sync mode" with the system in order to be able to access their user interfaces. We would just be trying to see any possible fluctuations by getting samples at various times. The modem still needs to be swapped out, just trying to see if you have a "doubleheader" issue going on here.
Adjustments to the power levels by them are not and can not be made on the fly.
06-27-2012 12:20 PM
The same pattern (cable modem can't connect in the morning until about 11:30 AM - then connection is stable until late at night) continues for a week and a half. I have had two tech visits: one changed a splitter, the other replaced a piece of coax cable near the pole - but neither repair fix the original problem.
I have been monitoring the cable modem (BEFCMU10 ver.3) status page and the only meaningful difference between the time if works and the time it does not (the "cable" LED flashing) is in the security line:
Security Enabled BPI+ (when it works)
Security Disabled Disabled (when it does not work)
The downstream and upstream signal levels and SNR are pretty much the same - whether connection is established or not.
©2011 Comcast | Investor Relations | Press Room | Corporate Blog | Privacy Statement | Visitor Agreement | Comcast.com Feedback | Site Map