Topic 'Re: [Connectivity] Net Drops Constantly' in forum 'Comcast HSI' - dslreports.com

Re: [Connectivity] Net Drops Constantly

Sat, 15 Dec 2012 13:46:54 EDT

owlyn posted : 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.

Re: [Connectivity] Net Drops Constantly

Sat, 15 Dec 2012 13:18:42 EDT

SallyWingles posted : 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.

Re: [Connectivity] Net Drops Constantly

Fri, 14 Dec 2012 07:37:40 EDT

SallyWingles posted : 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.

Re: [Connectivity] Net Drops Constantly

Fri, 14 Dec 2012 01:53:19 EDT

NetFixer posted :

said by 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?

The Comcast CSR was probably confusing the Online indicator with the Link indicator.

[att=1]

[att=2]
--
We can never have enough of nature.
We need to witness our own limits transgressed, and some life pasturing freely where we never wander.

Re: [Connectivity] Net Drops Constantly

Fri, 14 Dec 2012 00:51:47 EDT

SallyWingles posted : 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?

Re: [Connectivity] Net Drops Constantly

Fri, 14 Dec 2012 00:02:17 EDT

EG posted :

said by NetFixer:

Cable modems are not expensive cable line testers, and their line level readings are not to be taken seriously.

Yes !!Exactly !! Perhaps that is why some posters should not constantly and automatically say that "50 dB is fine" ?

Re: [Connectivity] Net Drops Constantly

Thu, 13 Dec 2012 23:48:52 EDT

telcodad posted : 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)

Re: [Connectivity] Net Drops Constantly

Thu, 13 Dec 2012 22:47:34 EDT

NetFixer posted :

said by telcodad:

While I'll agree that "very high" might have been a little too much, if some people are saying that they have had issues when their upstream levels hit 50 dBmV, then it is more than just "marginal." You also have to allow for a few dB of "headroom," given the normal, daily fluctuations most HFC systems experience.

I have stress tested my current SB6121 by moving it from its normal -3.5 db splitter leg to a -7 db splitter leg. When on the -3.5 db leg, my upstream levels read ~-45-48 dBmV. When on the -7 db leg, my upstream levels read ~-49-52 dBmV. I have left it on the -7 db leg (with at least one upstream channel at the -52 dBmV level) for multiple days, and my connection remained solid.

I have also tested my old (backup) D-Link DCM202 modem in a similar fashion, and its upstream level readings consistently read ~ 3 dBmV lower on either splitter leg than my SB6121. So, if my old D-Link had started failing at the -50 dBmV reading, would it really have failed at -50 dBmV, or would it have failed at -53 dBmV, or perhaps both of my cable modems are so far off in their readings that it would have actually failed at -55 dBmV ?

Cable modems are not expensive cable line testers, and their line level readings are not to be taken seriously. At best, the day to day readings on the same cable modem on the same connection, are good as a relative measure of conditions on a day to day basis for that specific modem on that specific connection. Those readings bear no real or reliable relationship to actual values measured with a high quality tester.
--
We can never have enough of nature.
We need to witness our own limits transgressed, and some life pasturing freely where we never wander.

Re: [Connectivity] Net Drops Constantly

Thu, 13 Dec 2012 22:05:22 EDT

owlyn posted : I've lost bonding at 50.25 (50 was the highest working level). At 53, I get disconnected.

Re: [Connectivity] Net Drops Constantly

Thu, 13 Dec 2012 21:54:58 EDT

telcodad posted :

said by NetFixer:

said by telcodad:

said by gar187er:

50 is fine.

Oh geez, we're not going to start another debate about what the maximum recommended upstream power level should be, are we? »Re: I think my signals are a little out of wack

I don't know, are we?

said by ExoticFish:

I would agree that 50-51 is too high. At 50 I had issues.

Well, it's starting to look that way! :)

said by NetFixer:

said by telcodad:

Well, while your modem downstream power levels and SNRs look fine, the upstream levels are very high.

Re: [Connectivity] Net Drops Constantly

Thu, 13 Dec 2012 21:45:22 EDT

ExoticFish posted : I would agree that 50-51 is too high. At 50 I had issues.
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Re: [Connectivity] Net Drops Constantly

Thu, 13 Dec 2012 21:29:34 EDT

NetFixer posted :

said by telcodad:

said by gar187er:

50 is fine.

Oh geez, we're not going to start another debate about what the maximum recommended upstream power level should be, are we? »Re: I think my signals are a little out of wack

I don't know, are we?

said by telcodad:

Well, while your modem downstream power levels and SNRs look fine, the upstream levels are very high.

Personally, I would have used the term "marginally high" or "potentially high", not "very high". Especially since the values shown in a typical cable modem's line stat page are not necessarily accurate.
--
We can never have enough of nature.
We need to witness our own limits transgressed, and some life pasturing freely where we never wander.

Re: [Connectivity] Net Drops Constantly

Thu, 13 Dec 2012 20:47:53 EDT

telcodad posted :

said by gar187er:

50 is fine.

Oh geez, we're not going to start another debate about what the maximum recommended upstream power level should be, are we? »Re: I think my signals are a little out of wack

Re: [Connectivity] Net Drops Constantly

Thu, 13 Dec 2012 18:50:28 EDT

gar187er posted : 50 is fine.

Re: [Connectivity] Net Drops Constantly

Thu, 13 Dec 2012 18:29:03 EDT

SallyWingles posted : 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.

Re: [Connectivity] Net Drops Constantly

Thu, 13 Dec 2012 16:49:02 EDT

telcodad posted :

said by SallyWingles:

Location - Barnegat, NJ
Issue - Constant Connection Drops every few minutes. Mainly noticed while online gaming, viewing movies from service, private network chats, and also Skype.

Cisco DPC3008 DOCSIS 3.0 Cable Modem (Rev 1.0) Bootloader Revision 2.3.1_r3 - d3000-v302r125532-120517a-L2VPN-CMCST.bin - Firmware build date May 17 11:31:04 2012
:
I recently received this modem as the old modem from Comcast was not allowing full speeds. The modems "online light" is always flashing Amber, and I was told by phone tech, this was normal. They said all looks fine on their end. My signals to them are just fine. They suggest it is a router issue.
:
Does anyone have any suggestions or ideas as to why this is happening? Here are the details you may require.
:
Now, we did flood here with Superstorm Sandy. I had to remove all of the insulation under my house, replacing it this weekend. I do run cat cables under the house. I had someone look at the wires, and they said they looked okay. HOWEVER, this problem started a month or two before the storm hit.
I would rather try to make sure there are no KNOWN issues first, then try replacing cat cables, router, and modem last.

If anyone can help shed some light on this I would greatly appreciate your help. Ideas, suggestions, tips, tools, links you name it I'm looking for it!

My Modems Info:

Model: Cisco DPC3008
Vendor: Cisco
Hardware Revision: 1.0
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

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: 0.7 dBmV 39.6 dB
Channel 2: 1.1 dBmV 39.5 dB
Channel 3: 1.3 dBmV 39.6 dB
Channel 4: 1.4 dBmV 39.6 dB
Channel 5: 0.9 dBmV 39.4 dB
Channel 6: 0.7 dBmV 39.4 dB
Channel 7: 0.3 dBmV 39.2 dB
Channel 8: 0.2 dBmV 39.5 dB

Upstream Channels
Power Level:
Channel 1: 50.5 dBmV
Channel 2: 49.8 dBmV
Channel 3: 51.0 dBmV
Channel 4: 0.0 dBmV

Well, while your modem downstream power levels and SNRs look fine, the upstream levels are very high. They should not exceed +50 dBmV for a D3 modem with multiple, bonded upstream channels.

Your problem sounds similar to another poster's who also had high upstream levels: »[Connectivity] Motorolla Surfboard SB5100 keeps resetting

You might want to check the condition of all cables/connectors and splitters that lead up to your modem. The modem should be connected to one output of a high-quality 2-way splitter (or maybe the -3.5dB output of a high-quality, unbalanced, 3-way one) connected to the cable as it first comes into your home. See: » Do I need to get an amplifer and active return? and »4 TVs & modem...how to run

A poor-quality splitter can have higher loss in the 5-42 MHz return (upstream) path, so replacing one with a high-quality one could help reduce those high upstream power levels. See: »Re: [Connectivity] Recommended splitter

[Connectivity] Net Drops Constantly

Thu, 13 Dec 2012 15:03:15 EDT

SallyWingles posted : Location - Barnegat, NJ
Issue - Constant Connection Drops every few minutes. Mainly noticed while online gaming, viewing movies from service, private network chats, and also Skype.

Cisco DPC3008 DOCSIS 3.0 Cable Modem (Rev 1.0) Bootloader Revision 2.3.1_r3 - d3000-v302r125532-120517a-L2VPN-CMCST.bin - Firmware build date May 17 11:31:04 2012

Belkin F5D8236-4 v1 Router 1.00.02 (Jul 31 2008 22:32:30)

The "routers" Internet flashes amber and goes back to solid blue. It will flash amber on average for 50 seconds, then go back to blue and stay blue on average for up to three to five minutes (this is not exact times) but it is the average.

I recently received this modem as the old modem from Comcast was not allowing full speeds. The modems "online light" is always flashing Amber, and I was told by phone tech, this was normal. They said all looks fine on their end. My signals to them are just fine. They suggest it is a router issue.

Sure, I can bypass the router all together, but my modem will NOT allow me to see any logs to know the issue is happening on their end. I've read many people replaced their routers and still have the same issue, so I want to try my hand at some Tech help before I spend money to replace my router that may not have a problem to begin with. Is there a way for me to collect data on my connection when I bypass the router? I see a login username and password for my modem, but I do not have access to this. Is there a log somewhere?

I've reset both Modem and Router. Comcast phone tech did his magic on his end as well. I've made sure my connection was set to Dynamic. My router/security log does not offer up anything at the times this happens, but I do see several listings for "sending OFFER to a local IP of one of our laptops, but this does not match the times the router net light goes amber.

Just while typing this up, my Internet icon flashed to amber for about 40 seconds, and went back to blue. It did this nine times while typing up this message.

Does anyone have any suggestions or ideas as to why this is happening? Here are the details you may require.

Windows 7 Pro 32bit

My Routers WAN is set to obtain from ISP
My Routers UPNP is Enabled

NVIDIA nForce Networking Controller. Driver claims its up to date 1.0.1.211
My networking controller properties are as follows:
Flow Control - Disabled
Interrupt Moderation - Enabled
Network Address - Not Present (radio dial selected)
Priority & VLAN - Priority Enabled
Speed/Duplex settings - Auto Negotiation
VLAN Id - value 1
Wake on Magic Packet - Enabled
Wake on Pattern Match - Enabled
The Power Management for this controller is set to
Allow the computer to turn off this device to save power (CHECKED)
All this device to wake the computer (CHECKED)
Only allow a magic packet to wake the computer (CHECKED)

Now, we did flood here with Superstorm Sandy. I had to remove all of the insulation under my house, replacing it this weekend. I do run cat cables under the house. I had someone look at the wires, and they said they looked okay. HOWEVER, this problem started a month or two before the storm hit.
I would rather try to make sure there are no KNOWN issues first, then try replacing cat cables, router, and modem last.

If anyone can help shed some light on this I would greatly appreciate your help. Ideas, suggestions, tips, tools, links you name it I'm looking for it!

My Modems Info:

Model: Cisco DPC3008
Vendor: Cisco
Hardware Revision: 1.0
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: 0.7 dBmV 39.6 dB
Channel 2: 1.1 dBmV 39.5 dB
Channel 3: 1.3 dBmV 39.6 dB
Channel 4: 1.4 dBmV 39.6 dB
Channel 5: 0.9 dBmV 39.4 dB
Channel 6: 0.7 dBmV 39.4 dB
Channel 7: 0.3 dBmV 39.2 dB
Channel 8: 0.2 dBmV 39.5 dB

Upstream Channels
Power Level:
Channel 1: 50.5 dBmV
Channel 2: 49.8 dBmV
Channel 3: 51.0 dBmV
Channel 4: 0.0 dBmV

Here is the ping info, but I did not notice the net drop while this happened.

Target Name: download.cnet.com
IP: 64.30.224.58
Date/Time: 12/13/2012 2:00:52 PM

1 0 ms 0 ms 0 ms 0 ms 0 ms . [192.168.2.1]
2 70 ms 69 ms * * 21 ms [**.**.***.*]
3 7 ms 9 ms 8 ms 8 ms 39 ms te-1-2-ur02.manahawkin.nj.panjde.comcast.net [68.85.77.25]
4 12 ms 12 ms 12 ms 11 ms 12 ms xe-9-0-1-0-ar03.plainfield.nj.panjde.comcast.net [68.85.35.97]
5 N/A N/A N/A N/A 15 ms te-0-3-0-0-cr01.atlanta.ga.ibone.comcast.net [68.86.91.237]
6 13 ms 13 ms 12 ms 13 ms 14 ms xe-11-1-0.edge1.NewYork2.Level3.net [4.71.186.13]
7 12 ms 13 ms 15 ms 17 ms 12 ms vlan51.ebr1.NewYork2.Level3.net [4.69.138.222]
8 18 ms 18 ms 17 ms 18 ms 16 ms ae-3-3.ebr2.Washington1.Level3.net [4.69.132.89]
9 24 ms 19 ms 28 ms 18 ms 18 ms ae-62-62.csw1.Washington1.Level3.net [4.69.134.146]
10 18 ms 49 ms 19 ms 48 ms 48 ms ae-61-61.ebr1.Washington1.Level3.net [4.69.134.129]
11 46 ms 32 ms 29 ms 31 ms 30 ms ae-2-2.ebr3.Atlanta2.Level3.net [4.69.132.85]
12 50 ms 50 ms 48 ms 49 ms 50 ms ae-7-7.ebr3.Dallas1.Level3.net [4.69.134.21]
13 54 ms 51 ms 60 ms 51 ms 49 ms ae-83-83.csw3.Dallas1.Level3.net [4.69.151.157]
14 49 ms 49 ms 49 ms 49 ms 50 ms ae-81-81.ebr1.Dallas1.Level3.net [4.69.151.150]
15 83 ms 81 ms 82 ms 83 ms 83 ms ae-1-8.bar1.Phoenix1.Level3.net [4.69.133.29]
16 98 ms 81 ms 84 ms 99 ms 81 ms ae-0-11.bar2.Phoenix1.Level3.net [4.69.148.114]
17 124 ms 83 ms 80 ms 83 ms 81 ms ae-5-5.car2.Phoenix1.Level3.net [4.69.148.121]
18 85 ms 84 ms 83 ms 85 ms 96 ms CBS-CORPORA.car2.Phoenix1.Level3.net [4.53.106.146]
19 83 ms 86 ms 84 ms 84 ms 85 ms ae2-0.io-phx1-ex8216-2.cnet.com [64.30.227.118]
20 84 ms 82 ms 83 ms 85 ms 84 ms phx1-rb-gtm2-tron-xw-lb.cnet.com [64.30.224.58]

Ping statistics for download.cnet.com
Packets: Sent = 5, Received = 5, Lost = 0 (0.0%)
Round Trip Times: Minimum = 82ms, Maximum = 85ms, Average = 83ms

Here is some smokeping data (about 30 minutes worth)
»/r3/smokeping.···d66faf97