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rocca
Start.ca
Premium
join:2008-11-16
London, ON
kudos:23

3 edits

3 recommendations

FAQ: Trouble-shooting (Cable)

Here are a few helpful tips for trouble-shooting cable internet issues:

Factory resetting your cable modem

To factory reset your modem, hold the 'reset' pin in on the back of the modem for 30 seconds or until all the lights flash and the modem begins to reset itself. This does much more than just 'rebooting' the modem as it causes all the memory from the prior configuration to be erased, rescans the channels on the node for the best set and requests a new copy of the profile to be sent down to it.

Modem signal levels

To get your modem details open »192.168.100.1 in your browser and go to the diagnostics, signal or statistics page. There you will see a grid showing which channels and frequencies are being used by the modem. Your receiving (forward) signal should be between -11 and +11 dBmV, and the transmission (return) signal level should be between +35 and +52 dBmV, and the BER (bit error rate) should all be 0%. If you have poor signals check the physical connectors that they are tight and remove any additional splitters that may be in the path. If the signals don't improve and you're able to connect the modem to the cable where it comes in your building that will help determine if the issue is with the outside or inside wiring. If you change the physical setup, it's best to make sure you label which cables went where so you can put things back afterwards.

Speed issues

The first step is always to factory reset the modem. If the problem still occurs after this it is important to remove the router/wifi from the equation. Testing over wifi or a handheld device is never accurate as you have to contend with interference from other wireless devices, cordless phones, baby monitors and even your microwave. Even just using a wired connection to your router does not eliminate all problems such as routers not capable of higher speeds because of CPU limits, QoS settings, memory leaks or other people on your network using the connection during your testing.

The second step is to make sure that you close down any software from your now directly connected computer, including background updates, backups, etc that could be using your connection in the background. Additionally some anti-virus and firewall software can sometimes be the source of the problem, try temporarily disabling it.

The third step if the problem persists is to check your physical setup, ie try replacing the network cable if you have a spare, or using a different computer to see if you have a problem with the network card on it.

If you're not able to resolve it please call us and we'd be happy to trouble-shoot with you and put in a ticket if there is an issue with your line.

Latency issues

Before testing specifically for latency issues it's important to reset your modem and do the same testing for speed issues as above, ie removing the router from the network while trouble-shooting. If speeds are good, but latency exists then there are a few additional steps to take.

First, it's important to determine what type of latency you're experiencing. It can either be a constant (ie high latency for minutes at a time) or intermittent (ie a few high latency packets intermixed with regular latency). It can also be related to time of day (ie happens any time during the day vs only happens during peak periods).

Second, it's important to determine where the latency is, ie to test your local node you should ping the gateway of your connection and if you experience the latency on that first hop then the following grid is the typical reason for the latency:

Constant or intermittent at peak: Node congestion. A factory reset of the modem might pick up a better channel set that is less congested.

Constant off-peak: Something on your system is saturating your upload, hunt it down and turn it off. If nothing really is running (check byte counters on your network card interface), then either an equipment or line failure.

Intermittent off-peak: Equipment or line failure.

If there is no latency on the first hop but exists further down, then use »WinMTR.net and run a 10 minute test to determine where the problem exists.

Splash screen

If you get a splash screen showing the incumbent cable carriers logo, that means that your modem is not properly registered or you are using a different modem than has been registered with us. If the later, reconnect the registered modem. If that is not the problem please verify the MAC address on the label matches the status screen at »192.168.100.1 and let our support team know the details.

jimmyfogg

join:2010-12-30

Re: [INTERNET] FAQ: Trouble-shooting (Cable)

This deserves a Sticky.


rocca
Start.ca
Premium
join:2008-11-16
London, ON
kudos:23
Already requested.

System

(topic move) [INTERNET] FAQ: Trouble-shooting (Cable)

Moderator Action
The post that was here, has been moved to a new topic .. »[Cable] Trouble-shooting re levels


New2Start

@start.ca
reply to rocca

Re: [INTERNET] FAQ: Trouble-shooting (Cable)

Shouldn't the "forward" signal be between -11 and 11 dBmV? I believe the SNR is measured in dB and should be 33 dB or higher with a DOCSIS 3 modem??


rocca
Start.ca
Premium
join:2008-11-16
London, ON
kudos:23
Yes thanks, typo. Fixed.

geokilla

join:2010-10-04
North York, ON
Start. Why you so awesome?


rocca
Start.ca
Premium
join:2008-11-16
London, ON
kudos:23
So we get the best customers!


DrugTito

join:2013-01-17
canada
hahahaha, good one.

londoner1

join:2007-04-26
London, ON
reply to rocca

Re: FAQ: Trouble-shooting (Cable)

On the SB6120 there isn't a physical reset button. To reset go to 192.168.100.1 Configuration and click Reset All Defaults


TypeS

join:2012-12-17
London, ON
kudos:1
Reviews:
·TekSavvy DSL
·TekSavvy Cable
said by londoner1:

On the SB6120 there isn't a physical reset button. To reset go to 192.168.100.1 Configuration and click Reset All Defaults

Add all Motorolas to that, SB5101N, SB6120 and SB6121 all have software factory reset methods.

Something else to add as well, a quirck with cable modems I have come across when troubleshooting. When switching devices connected to the WAN Ethernet port on a modem, logic dictates you power cycle the device after it , but I find power cycling the modem works best when swapping between router and a computer for troubleshooting. If trying with a 3rd device, a factory reset is often needed to clear the MAC address table as often CMs will limit to remembering only 2.


rocca
Start.ca
Premium
join:2008-11-16
London, ON
kudos:23
Good point, small correction is that it's the CMTS that prevents handing out a 3rd IP to the CM, which is why a reset clears that out.


rocca
Start.ca
Premium
join:2008-11-16
London, ON
kudos:23
Speed issues trouble-shooting (continued)

One of the biggest causes of intermittent speed complaints, particularly on the lower speed packages such as the "Legacy Basic 6/0.256" plan, is that when the upload traffic is at capacity you'll experience poor performance surfing and speed tests will show practically nil for the upload and well below your download capability even if you're not downloading anything.

The reason for this is due to the way TCP/IP works with acknowledgement packets not being able to leave your connection because the upload capacity is being saturated doing other things such as file transfers, cloud backup, posting videos online or interactive video chat/conferencing. The article at »www.cyberconnect.co.za/blog/mark···rade-off does a great job explaining the technical reasons why saturating your upload will cause poor download speeds and while it references ADSL the exact same behaviour applies to any type of internet service where the upload speed is much slower than the download speed.

If you have QoS capabilities in your router then you can improve download performance by setting the upload rate to just below what your maximum speed is so that at least the acknowledgement packets aren't held up, however the only real solution is to ensure you have a package adequately sized to handle all your upload and download needs.
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