| [Speed] somewhat shaky speeds ever since upgrade to 100m hey folks. i've had the "business-class" Comcast internet service in Nashville, TN for about a year. No problems to speak of, the only issue is actually when Comcast called me because, apparently, my modem was disconnecting/reconnecting for short periods. I never noticed any issues, but they came out and replaced my first one anyway. Both models are SMCD3G's. Initially I was on the 50/10 tier, and speeds were great; super consistent all around.
I recently upgraded to the 100/20 service as it was the same price. Now, speeds seem a bit less consistent; overall tests from speedtest.net are usually around 105, but sometimes 102 to 98, and during the test the speed sometimes drops to ~92-93. As well, occasionally the test will drop entirely for about 1.5 seconds. The same thing happens on any file download that is rare enough to max out the full 100 megs. Pingest.net never reports any packet loss, although during an unrelated suppport call the tech mentioned that she was getting packet loss inside this modem...
All testing for this purpose has been done from my laptop directly into the modem, configured with my static IP (not for too long, for safety's sake). I don't think it's the router, as this behavior is identitcal with or without it. No network issues are noted on the laptop, which regularly sends/receives >100GB a day on the LAN.
Is this normal, can Comcast not always handle 100mbps reliably? I would think they could... |
|
|
|
| I was under the impression most setups running 100 for Comcast had 8 downstream channels for the modem, but yours only shows 4. Power is a bit high on that last channel but if that's the highest upward swing then that shouldn't be a problem. |
|
| hmmmm.... on the day that I upgraded the service, I do know that it took about 3.5-4 hours for the modem to come back online.... it just kept resetting itself the whole time. multiple unplugs/replugs didn't change anything. finally it came back online. idk if that might signify anything.... |
|
 Chris 313Come get somePremium
join:2004-07-18
Houma, LA
 ·Vonage
 ·Comcast
·Comcast Digital ..
 ·AT&T U-Verse
4 edits
recommend1 | said by train_wreck:hmmmm.... on the day that I upgraded the service, I do know that it took about 3.5-4 hours for the modem to come back online.... it just kept resetting itself the whole time. multiple unplugs/replugs didn't change anything. finally it came back online. idk if that might signify anything....
Your DS power levels are at the high end of being acceptable. Another thing to think about, is the possible issue of the almost 3 dBmV distance between 2 of the channels. Channel bonding has issues the further apart the channels slide from each other. You really want no more than 2 dBmV between channels.
See here: »Comcast High Speed Internet FAQ »What should my Signal Levels be?
And the modem you use for Biz class, while capable of 105/20 no problem, is only a 4x4 model. You may want to consider buying one of these (not to mention it was recently approved for Biz class use, and you could save yourself rental fees)
»www.amazon.com/ARRIS-Motorola-Su···ola+6141
You can find this modem at Best Buy and they price match with Amazon for best price. It's also an 8x4 modem vs the 4x4 model you have now.
Do you use the SMCD3G as a router too? If so and you decide to buy the modem I listed, you'll need to get your own separate router. These are 3 good models I've seen:
»www.amazon.com/ASUS-Dual-Band-Wi···+RT-N66U (A friend has one of these and raves about it. It can do 105/20 no problem)
»www.amazon.com/RT-N66U-Dual-Band···+RT-N66U (I have one of these, with no complaints of speed or performance. I use Blast at 50/10 and get 65/11 with the Moto 6141 and Asus RT-N66U combo)
»www.amazon.com/RT-AC66U-Dual-Ban···+RT-N66U (The successor to the model I have.)
Also: Out of curiosity, what OS are you using?
Hope this helps you begin to solve your problem. If you have any questions or need help, come back and ask away. |
|
| said by Chris 313:said by train_wreck:hmmmm.... on the day that I upgraded the service, I do know that it took about 3.5-4 hours for the modem to come back online.... it just kept resetting itself the whole time. multiple unplugs/replugs didn't change anything. finally it came back online. idk if that might signify anything....
Your DS power levels are at the high end of being acceptable. Another thing to think about, is the possible issue of the almost 3 dBmV distance between 2 of the channels. Channel bonding has issues the further apart the channels slide from each other. You really want no more than 2 dBmV between channels. See here: » Comcast High Speed Internet FAQ » What should my Signal Levels be?And the modem you use for Biz class, while capable of 105/20 no problem, is only a 4x4 model. You may want to consider buying one of these (not to mention it was recently approved for Biz class use, and you could save yourself rental fees) » www.amazon.com/ARRIS-Motorola-Su···ola+6141You can find this modem at Best Buy and they price match with Amazon for best price. It's also an 8x4 modem vs the 4x4 model you have now. Do you use the SMCD3G as a router too? If so and you decide to buy the modem I listed, you'll need to get your own separate router. These are 3 good models I've seen: » www.amazon.com/ASUS-Dual-Band-Wi···+RT-N66U (A friend has one of these and raves about it. It can do 105/20 no problem) » www.amazon.com/RT-N66U-Dual-Band···+RT-N66U (I have one of these, with no complaints of speed or performance. I use Blast at 50/10 and get 65/11 with the Moto 6141 and Asus RT-N66U combo) » www.amazon.com/RT-AC66U-Dual-Ban···+RT-N66U (The successor to the model I have.) Also: Out of curiosity, what OS are you using? Hope this helps you begin to solve your problem. If you have any questions or need help, come back and ask away. Hey thanks for the info... im not sure theres much i can do about the power levels, is there? Also in regards to the modem, i have a static ip, and according to comcast i cannot use my own modem. I have to use theirs.
My router is a linux pc w/multiple gigabit NICs, and i never have had any issues with it. My testing has been done on linux & win7. No discernable difference. |
|
Chris 313Come get somePremium
join:2004-07-18
Houma, LA Reviews:
·Vonage
·Comcast
·Comcast Digital ..
·AT&T U-Verse
recommend1 | said by train_wreck:said by Chris 313:said by train_wreck:hmmmm.... on the day that I upgraded the service, I do know that it took about 3.5-4 hours for the modem to come back online.... it just kept resetting itself the whole time. multiple unplugs/replugs didn't change anything. finally it came back online. idk if that might signify anything....
Your DS power levels are at the high end of being acceptable. Another thing to think about, is the possible issue of the almost 3 dBmV distance between 2 of the channels. Channel bonding has issues the further apart the channels slide from each other. You really want no more than 2 dBmV between channels. See here: » Comcast High Speed Internet FAQ » What should my Signal Levels be?And the modem you use for Biz class, while capable of 105/20 no problem, is only a 4x4 model. You may want to consider buying one of these (not to mention it was recently approved for Biz class use, and you could save yourself rental fees) » www.amazon.com/ARRIS-Motorola-Su···ola+6141You can find this modem at Best Buy and they price match with Amazon for best price. It's also an 8x4 modem vs the 4x4 model you have now. Do you use the SMCD3G as a router too? If so and you decide to buy the modem I listed, you'll need to get your own separate router. These are 3 good models I've seen: » www.amazon.com/ASUS-Dual-Band-Wi···+RT-N66U (A friend has one of these and raves about it. It can do 105/20 no problem) » www.amazon.com/RT-N66U-Dual-Band···+RT-N66U (I have one of these, with no complaints of speed or performance. I use Blast at 50/10 and get 65/11 with the Moto 6141 and Asus RT-N66U combo) » www.amazon.com/RT-AC66U-Dual-Ban···+RT-N66U (The successor to the model I have.) Also: Out of curiosity, what OS are you using? Hope this helps you begin to solve your problem. If you have any questions or need help, come back and ask away. Hey thanks for the info... im not sure theres much i can do about the power levels, is there? Also in regards to the modem, i have a static ip, and according to comcast i cannot use my own modem. I have to use theirs. My router is a linux pc w/multiple gigabit NICs, and i never have had any issues with it. My testing has been done on linux & win7. No discernable difference. You're welcome for the info, but you're right. Your set up is more then likely ok and it is a Comcast issue on their end that has to be looked at if the channels are spread out more then is ideal and causing you problems on your end. And you're right as well, if you have Statics, you have to use Comcast provided hardware. Why that is, I'm sure the reason is ridiculous. But it could be worse. Just ask 99% of Comcast phone users about them needing to use Comcast provided hardware. (I used to be in that boat.)
Other then that, I'm not sure what else can be done to help you from this end. It's on Comcast to unscrew whatever it is. |
|
| reply to train_wreck
the problem is on 4 channels theres only 160mbits of bandwidth, if theres another user on your node (on mine theres around 450) with a higher tier using the same channels and happens to be using it, 160mbits can get clogged easily |
|
| reply to Chris 313
word.
anyone know if comcast provides any modem at all that is capable of 8 channel bonding? |
|
Chris 313Come get somePremium
join:2004-07-18
Houma, LA Reviews:
·Vonage
·Comcast
·Comcast Digital ..
·AT&T U-Verse
| said by train_wreck:word.
anyone know if comcast provides any modem at all that is capable of 8 channel bonding?
Maybe. I'm not too familiar with the modems they carry these days. As Jason says here: »[Speed] Heads-Up: Time to Replace Your DOCSIS 2.0 Modem
There are very few pure modems carried by Comcast these days. These days, they're shifting to Gateway devices that do modem/router/phone all in one. And come with all the problems a combo device brings when something goes wrong or is not as flexible as a user would like settings wise.
According to here: »mydeviceinfo.comcast.net/ Comcast does have some pure modems on the list, see for yourself. Residential, Extreme 105, and show only latest models (Docsis 3 and above)
But that is residential, not Biz, which you have, and only only shows 2 modems (Modem/router devices like you already have)
When shopping for any modem, or getting swapped, you want one that's 8x4 or better. Comcast is beginning to roll out units that are between 8x4 and 24x8. Be a fun next couple years.
Sorry I can't help you more. |
|
 Anonymous_AnonymousPremium
join:2004-06-21
127.0.0.1
kudos:2
·Time Warner Cable
| reply to Chris 313
said by Chris 313:said by train_wreck:hmmmm.... on the day that I upgraded the service, I do know that it took about 3.5-4 hours for the modem to come back online.... it just kept resetting itself the whole time. multiple unplugs/replugs didn't change anything. finally it came back online. idk if that might signify anything....
Your DS power levels are at the high end of being acceptable. Another thing to think about, is the possible issue of the almost 3 dBmV distance between 2 of the channels. Channel bonding has issues the further apart the channels slide from each other. You really want no more than 2 dBmV between channels. ou have any questions or need help, come back and ask away. 22.7 =36.8db
29.5 =38.5db
36.3= 39.2db
also the down stream is
channel 2
channel 1
channel 3
channel 4
You are just looking at is incorrectly....
sometimes modems do not connect in a very specific order
i.e
1 Locked QAM256 5 687000000 Hz -0.9 dBmV 35.4 dB
2 Locked QAM256 1 663000000 Hz -0.6 dBmV 35.7 dB
3 Locked QAM256 2 669000000 Hz -1.1 dBmV 35.4 dB
4 Locked QAM256 3 675000000 Hz -0.9 dBmV 35.4 dB
5 Locked QAM256 4 681000000 Hz -1.1 dBmV 35.2 dB
6 Locked QAM256 6 693000000 Hz -1.0 dBmV 35.2 dB
7 Locked QAM256 7 699000000 Hz -1.2 dBmV 35.1 dB
8 Locked QAM256 8 705000000 Hz -1.2 dBmV 35.0 dB |
|
Chris 313Come get somePremium
join:2004-07-18
Houma, LA Reviews:
·Vonage
·Comcast
·Comcast Digital ..
·AT&T U-Verse
| said by Anonymous_:said by Chris 313:said by train_wreck:hmmmm.... on the day that I upgraded the service, I do know that it took about 3.5-4 hours for the modem to come back online.... it just kept resetting itself the whole time. multiple unplugs/replugs didn't change anything. finally it came back online. idk if that might signify anything....
Your DS power levels are at the high end of being acceptable. Another thing to think about, is the possible issue of the almost 3 dBmV distance between 2 of the channels. Channel bonding has issues the further apart the channels slide from each other. You really want no more than 2 dBmV between channels. ou have any questions or need help, come back and ask away. 22.7 =36.8db 29.5 =38.5db 36.3= 39.2db also the down stream is channel 2 channel 1 channel 3 channel 4 You are just looking at is incorrectly.... sometimes modems do not connect in a very specific order So? What does that have to do with anything? My modem's set up similarly with the channels all over the place as well |
|
