| Blast 16/2 running at half speed I just got comcast's Blast service but from all the tests I've run I only seem to be reaching 8Mbps. I've googled variations of this problem but have not been able to find either a solid solution or explanation.
My tests have been a consistant:
I also tried downloading three large files from fast servers using a bandwidth meter to monitor my speeds but it peaked at about 11Mbps.
I'm in the southern part of San Francisco; the modem I'm using is the RCA DCM425. I tried both my laptop and my desktop PCs hooked directly into the cable modem but got the same results.
Is this just the nature of the Blast service? |
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1 edit | You don't have anything listed here about your setup or your levels, outside of the model of your modem...
I didn't get speed test results that were consistent with 16/2 until I did a firmware update on my older Linksys router. Of course, I didn't both to try that until I had confirmed that my Scientific Atlanta DPC2100 had the right bootfile. |
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| reply to iamdak
As I stated; I tried both my desktop and and laptop directly connected via ethernet to the modem itself. They both reported 8Mpbs with about 3Mbps up consistently. As per the diagnostics of my modem:
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Forward Path:
Signal Acquired at 723.000 MHz
SNR: 34.7 dB
Received Signal Strength: -8.7 dBmV
Bit Error Rate: 0.000 %
Return Path:
Connection: Acquired
Frequency: 32.0 MHz
Power Level: 47.3 dBmV
Channel ID: 7
Modulation: 16 QAM |
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| My bad, it was more of a passing mention and it didn't really stand out when I looked over what you'd posted.
I'd definitely try and check your config file, or what the modem reports the speed caps at. |
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|  Honestly... it took me a bit to find where I typed it also; something that important should probably stand out better 
I'm not exactly sure which config file you're refering to. If I missed a link to something explaining this I'd appreciate that very much. The diagnostics page of the modem isn't very informative beyond what I pasted above but from poking about the web I believe the modem goes up to 32Mbps (though I could be dreadfully mistaken  ). |
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| Ok -- so I did some extra digging and was able to get my modem to display the config file info. This is what the log showed:
SW Download INIT - Via Config file d11_m_dcm425_speedtierextr...
'speedtierextr' seems to be the config file name. |
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| Did you try rebooting the cablemodem? |
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 JohkalCool CatPremium,MVM
join:2002-11-13
Happy Valley
kudos:5 | reply to iamdak
What are the TCP settings for the PC & laptop? |
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| reply to Not a name
yup! Tried rebooting the modem and my computers. I also tried reseting the modem by tapping the reset button and by holding it down for 15-20 seconds.
I'm still getting an average down rate of 8500 kbps. |
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| reply to Johkal
The TCP settings in windows for both PCs are the standard Obtain IP and DNS automatically. Is there something more specific I can dig up?
(and I rebooted and reset everything several times  ) |
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JohkalCool CatPremium,MVM
join:2002-11-13
Happy Valley
kudos:5 | Run a tweak test on both and post results: »/tweaks |
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| Desktop:
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Receive Window (RWIN): 65535
Window Scaling: 0
Path MTU Discovery: ON
RFC1323 Window Scaling: ON
RFC1323 Time Stamping: OFF
Selective Acks: ON
MSS requested: 1460
TTL: unknown
TTL remaining: 108
TOS flags: none set
---
Actual data bytes sent: 1031301
Actual data packets: 708
Max packet sent (MTU): 1500
Max packet recd (MTU): 1500
Retransmitted packets: 5
sacks you sent: 71
pushed data pkts: 128
data transmit time: 7.072 secs
our max idletime: 235.3 ms
transfer rate: 138267 bytes/sec
transfer rate: 1106 kbits/sec
transfer efficiency: 99%
---
Minimum ping: 98.27 ms
Maximum ping: 102.79 ms
Ping stability:
99.55 99.60 102.79 100.57 99.43 98.27 99.15 101.26 102.32 99.56
:: Laptop in a min :: |
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| Laptop:
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Receive Window (RWIN): 65535
Window Scaling: off
Path MTU Discovery: ON
RFC1323 Window Scaling: OFF
RFC1323 Time Stamping: OFF
Selective Acks: ON
MSS requested: 1460
TTL: unknown
TTL remaining: 108
TOS flags: none set
---
Actual data bytes sent: 1026921
Actual data packets: 705
Max packet sent (MTU): 1500
Max packet recd (MTU): 1500
Retransmitted packets: 2
sacks you sent: 75
pushed data pkts: 95
data transmit time: 3.721 secs
our max idletime: 314.5 ms
transfer rate: 247515 bytes/sec
transfer rate: 1980 kbits/sec
transfer efficiency: 99%
---
Minimum ping: 98.57 ms
Maximum ping: 113.58 ms
Ping stability:
98.57 99.45 99.31 113.58 102.64 99.98 108.41 109.38 99.59 99.22
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Both suggest an RWIN of between 154760 and 410260. |
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 hobgoblinSortof AgoblinPremium
join:2001-11-25
Orchard Park, NY
kudos:4 | said by iamdak :
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Both suggest an RWIN of between 154760 and 410260.
You might want to do that then!
Hob
--
"A foolish consistency is the hobgoblin of little minds."
- Ralph Waldo Emerson
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| Using the suggested app I put the RWIN to 300,000. The speed tests still come out to 8500 avg.
I'll try it again though on my desktop! |
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| Tried on my desktop; no dice. Still getting 8000-8500 average. |
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 oO
@comcast.net | reply to iamdak
When did you exactly get your service? I was hitting 16mb mark the past week but it dropped to 8-9mb mark yesterday to today. I live in San Fran as well. |
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| reply to iamdak
Sounds like we may have the same problem |
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| This is the same issue in chicago. I dont think comcast has he capacity to do this yet and they just up and did it. i cant get it fixed and am ready to change providers to actually get some kind of internet. My internet isn't working well either. |
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| My internet was activated on Saturday (yesterday). I've since noticed it go as far as 11.5Mbps with the rare spike to 14, but it averages about 8.5Mbps. I feel its worth mentioning that 8.5Mbps is still fantastic, but I'm trying to gauge whether its worth getting a slower (cheaper) service instead of paying for 16Mbps and getting only 8. |
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