US Cable Support > Comcast HSI > [Connectivity] Net Drops Constantly

[Connectivity] Net Drops Constantly

My TV started acting up, pixels, stuttering, going very fast, and then slow. I called Comcast, to tell them my upstream info, along with what I've mentioned above and they are sending someone out this Sunday. I will use this information when the tech arrives. I am thinking there is damage from the flooding we had with Superstorm Sandy.

Please feel free to offer anymore advice or tips because I really hope to see positive results when the tech is done.

reply to telcodad
50 is fine.

reply to SallyWingles
I would agree that 50-51 is too high. At 50 I had issues.
--
»www.VAJeeps.com
»www.BronzedBod.com

reply to NetFixer

reply to NetFixer
I've lost bonding at 50.25 (50 was the highest working level). At 53, I get disconnected.

reply to telcodad

Given the variations in the architectures of and equipment used in the various HFC systems Comcast has cobbled together over the years, I would think it is also possible that in some systems (like yours), upstream power levels of 51 dBmV or slightly more may not be a problem, while in other systems (like in ExoticFish 's and owlyn 's), levels that high do cause issues.

The differences between different brands/models of modems can also enable some of them to perform OK at >50 dBmV levels.

Like they say - YMMV.

EDIT: Looks like the upstream power limit is determined by the modem and, as some posters have stated before, the number of upstream channels. From page 3 of the data sheet for the Moto SB6121 (»www.motorola.com/staticfiles/Sup···heet.pdf ):

Upstream Operating Level Range Level range per channel:

(Multiple Transmit Channel mode disabled, or only Multiple Transmit Channel mode enabled with one channel in the TCS)
TDMA
Pmin to +57 dBmV (32 QAM, 64 QAM)
Pmin to +58 dBmV (8 QAM, 16 QAM)
Pmin to +61 dBmV (QPSK)

Level range per channel (two channels in the TCS)
TDMA
Pmin to +54 dBmV (32 QAM, 64 QAM)
Pmin to +55 dBmV (8 QAM, 16 QAM)
Pmin to +58 dBmV (QPSK)

Level range per channel (three or four channels in the TCS)
TDMA
Pmin to +51 dBmV (32 QAM, 64 QAM)
Pmin to +52 dBmV (8 QAM, 16 QAM)
Pmin to +55 dBmV (QPSK)

reply to NetFixer

reply to SallyWingles
I was just reading about this modem at the Cisco website. Here is a quote that caught my attention. It reads as follows.

This article will show you what to do if the Online LED of your cable modem is blinking. A blinking Online LED means that your modem is unable to access the network. To resolve this, follow the steps below:

Checking if the cable modem is registered
Checking the modems physical connections
Powercycling the modem

When I spoke to the Comcast Tech on the phone, I did tell him I had concerns about the modems Online link was always blinking amber. I was told correct and NORMAL to do that. However, the Cisco website is not agreeing with the Comcast Tech. Can anyone confirm which is the correct status of this modems Cisco DPC3008 DOCSIS 3.0 online status light?

reply to SallyWingles
Can someone that understands the smokeping readings, let me know their thoughts? I've been running it for almost 24hrs. The link is in my OP, at the bottom.

Thank you in advance.

OKay, today I got so sick of it so tried again (bypassing the router). Unplugged the router, plugged my modem cable into my PC, and using a cat6 cable.

So far its been going very well, but I cannot say for sure if the modem has dropped connection for a few seconds here and there because I cannot actually see more detailed LOGS for my modem. I wish I could

BTW, here is my current readings from my modem:

Model: Cisco DPC3008
Vendor: Cisco
Hardware Revision: 1.0
Serial Number: 244591653
MAC Address: bc:c8:10:2d:de:24
Bootloader Revision: 2.3.1_R3
Current Software Revision: d3000-v302r125532-120517a-L2VPN-CMCST
Firmware Name: d3000-v302r125532-120517a-L2VPN-CMCST.bin
Firmware Build Time: May 17 11:31:04 2012
Cable Modem Status: Operational
Wireless Network:


Cable Modem State
DOCSIS Downstream Scanning: Completed
DOCSIS Ranging: Completed
DOCSIS DHCP: Completed
DOCSIS TFTP: Completed
DOCSIS Data Reg Complete: Completed
DOCSIS Privacy: Enabled

Downstream Channels
Power Level: Signal to Noise Ratio:
Channel 1: 0.6 dBmV 39.6 dB
Channel 2: 1.0 dBmV 39.8 dB
Channel 3: 0.9 dBmV 39.5 dB
Channel 4: 1.0 dBmV 39.5 dB
Channel 5: 0.5 dBmV 39.3 dB
Channel 6: 0.5 dBmV 39.2 dB
Channel 7: 0.2 dBmV 39.2 dB
Channel 8: 0.0 dBmV 39.4 dB

Upstream Channels
Power Level:
Channel 1: 50.8 dBmV
Channel 2: 50.0 dBmV
Channel 3: 51.0 dBmV
Channel 4: 0.0 dBmV

Just to note, I did see an upstream level yesterday of 52, but its been average of 50-51.

My Router is the Belkin F5D8236-4 v1 Wireless N and I've ran this router without any problems for the last three years. I am very curious as to what can cause issues suddenly come up with a router. Can routers go bad in such a short time? I take great care of my electronics, its has not been dropped, hit, or anything like that. Nothing new has been added either. Can anyone enlighten me?

I would like to understand this issue before I go out and spend $100+ on a new router? I have a large family, and with all the laptops, gaming systems, phones, tablets in this house I really need a router... but making sure this current router is actually on the fritz is my main concern at the moment. Just to clarify ... I myself use a hardwired PC, it was the entire network losing Internet (both hardwired and wireless)

I do have a Comcast tech coming out tomorrow, and this is mainly because we had flooding in the crawl space, all the way up to the flooring, and the insulation was soaked, we removed it all, and will be adding new insulation this weekend, so its perfect timing for the tech to come here. I have great concerns for the splitter/cable work the tech did under my house years ago. The way I see is we might as well have them do it now, and not have to call them out later.

So, in the meantime, I am trying to educate myself on what can cause a router to drop net connection up to 40 times and hour? The only changes here was a new modem (docsis 2 to docsis 3) and the flooding from Superstorm Sandy here in the Barnegat area.

I'm hopeful someone can offer some ideas while I wait.

Your upstream is at the upper end of acceptable and is very likely responsible for your problems. The Comcast tech should be able to determine where the problem is occurring.