mclaver
join:2001-04-28
Minneapolis, MN | SB6120 and number of Channels Bonded I have had Comcast Ultra for a week and it is great. Yesterday I was receiving over 40Mb download and my SB6120 was Bonded to three channels. Today I am only getting in the mid 20Mb range which is not bad, but I notice that my SB6120 is only bonded to one channel. What determines how many channels the SB6120 bonds too, and can the number of channels you are bonded to impact speed? Thanks!
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1 edit | What are the RF stats
at this point its just a guess but
if you are border line on the channels then its possible that 2 are dropping due to going out of range |
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mclaver
join:2001-04-28
Minneapolis, MN | Yesterday, the SNR on all three channels were between 37-39 db. Today the one channel is 37 db. My understand is that 37 db is not a bad SNR. |
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| 37DB snr is good but what are the other stats (downstream power upstream power)
(I think the differant channels might develop differant SNR's so the good one is still good but maybe the lesser ones droped) |
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| reply to mclaver
I am on an SB6120 with the ultra 22/5 tier, and I have two channels bonded. They have different SNR's on each respective channel, I think it's 35 and 34 db on mine. |
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mclaver
join:2001-04-28
Minneapolis, MN | reply to DarkLogix
Actaully, I think the other two channels had higher SNR but I did not write it down. Down load speed does not seem to be impacted that much. Here are all the values for my one channel that is still bonded.
Downstream Bonding Channel Value
Channel ID 45
Frequency 735000000 Hz
Signal to Noise Ratio 36 dB
Downstream Modulation QAM256
Power Level The Downstream Power Level reading is a snapshot taken at the time this page was requested. Please Reload/Refresh this Page for a new reading
6 dBmV
Upstream Bonding Channel Value
Channel ID 2
Frequency 32000000 Hz
Ranging Service ID 2418
Symbol Rate 5.120 Msym/sec
Power Level 39 dBmV
Upstream Modulation [3] QPSK
[3] 64QAM
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 EGThe wings of lovePremium
join:2006-11-18
Union, NJ
kudos:9
3 edits | said by mclaver:Here are all the values for my one channel that is still bonded. Whatever is worth here. One single channel can not be "bonded". There must be at the minimum two channels either per upstream or per downstream to be considered to be "bonded" channels. |
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mclaver
join:2001-04-28
Minneapolis, MN | Sorry for not being clear. My original question was why did I have three channels bonded yesterday with over a 40Mb download speed and today I have only one channel, and a download speed in the 20Mb range.
How many channels should be bonded with an SB6120 modem, what determines how many channels will be bonded, and does additional bonded channels increase download speed? |
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EGThe wings of lovePremium
join:2006-11-18
Union, NJ
kudos:9
2 edits | said by mclaver: and does additional bonded channels increase download speed? Yes. And additional bonded up/down channels increase the total bandwidth available for all subscribers on any particular node/segment so that they all may more or less equally share in the increased throughput speeds.
I'm sorry but that is the only thing that I can answer correctly as I am not a CC employee. |
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 espaethDigital PlumberPremium,MVM
join:2001-04-21
Minneapolis, MN
kudos:2 | reply to mclaver
I've noticed that if they perform maintenance on the CMTS and my modem loses sync sometimes only one channel will be locked when service returns. A powercycle of the cable modem will usually return sync to all 3 channels. |
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| reply to mclaver
each channel provides roughly 38Mbit
so on ultra you only "really" need one but if you get more then Powerboost can have more room to work
and if you only get one its easier for that one to get congested and thus see lower speeds |
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mclaver
join:2001-04-28
Minneapolis, MN | reply to espaeth
I tried what you suggested and powered down my modem. I am now bonded to three channels again and my download speeds jumped back up to 47 Mbs, my upload speeds are 12.5 Mbs. Not bad for an Ultra customer. I will have to watch this if I ever do a large download, because that made a lot of difference. Using channels 45, 46, 47 and all three channels have a 36 DB SNR. |
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| reply to mclaver
I checked and that modem can bond upto 4 channels so maybe at some point in the future you'll get 4 bonded
(I hope Comcast gets more stable and/or cable modems get more dynamic and get to the point of re-syncing on their own w/o having to power cycle)
but this might be to much to hope for(It would be great if they get this done by the time D3 getts here) |
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mclaver
join:2001-04-28
Minneapolis, MN | I thought I was on D3. That was why they installed the SB6120. I have an emta that has an Ethernet connection, but I was told for Ultra you needed D3. Also, I did not think D2 supported Bonding channels |
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| yes D3 is required for channel bondig
and you have a D3 modem and are on D3 |
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EGThe wings of lovePremium
join:2006-11-18
Union, NJ
kudos:9
2 edits | reply to DarkLogix
said by DarkLogix:each channel provides roughly 38Mbit That would be dependant on the actual width of the channel, and the particular modulation scheme being used. |
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| well of course but talking downstream 256QAM |
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mclaver
join:2001-04-28
Minneapolis, MN | I have another question. I am consistently getting over 45 Mbs on all of my computers except one. That one is only getting around 20 Mbs. It is running Win 2K. Other computers running Win 2K are getting over 45 Mbs. I ran DrTCP on that machine and it did not do anything. Any ideas of why one machine is getting only half the download speeds as another one, on the same network, with the same operating system? |
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| how is it connected (wired/wireless) and how old is it? |
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mclaver
join:2001-04-28
Minneapolis, MN | It is wired and running 100Mb / full duplex ethernet. It is not a distance issue as machines the same distance from the switch get the same speed. There are two Ethernet NICs on the motherboard, one an Nforce4 and one a Marval. They both have the problem. It is a Socket 939 motherboard so it is a couple of years old. |
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