ipman
join:2010-08-31
San Jose, CA | What speed should 768kbps subscriber get? I am visiting a senior's home and they have subscribed to the lowest tier of DSL service. I believe the 768kbps down/384kbps up plan. I see from the wireless gateway (2-wire 2701HG), it says 1536kbps down/384kbps up. Maybe this is the line rate? Anyway, their phone bill says 768kbps so it can't be wrong.
However, speed test shows that their speed tops off at 680kbps/340kbps. This is less than 90% of the advertised speed. I tried using 2 PCs and results are very similar. One of the PC is connected directly to the gateway. I also checked the statistics on the gateway and error counts are very low, mostly zeros.
Is this what one should expect for traditional DSL service? Only 85-90% of the advertised bandwidth? |
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 wayjacPremium,MVM
join:2001-12-22
Indy
kudos:1 | said by ipman:I see from the wireless gateway (2-wire 2701HG), it says 1536kbps down/384kbps up. Maybe this is the line rate? Anyway, their phone bill says 768kbps so it can't be wrong The figures can be called "line rate" I prefer to call them sync rates
You should expect about 80% of the
sync rate for the pppoe dsl service?
If the sync rates are 768/384 that is the basic speed plan
The basic plan is the slowest speed plan
If the sync rates are 1536/384 that is the express speed plan |
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Reviews:
 ·Millenicom
 ·AT&T Southeast
·Verizon Wireless..
| reply to ipman
In the FCC Broadband Report, »transition.fcc.gov/cgb/measuring···Full.pdf, you can find in Chart 11 that DSL does not deliver the full speed advertised. It is below advertised by 10% to 20%. In my personal experience using testmy at »testmy.net/ for data rate checking I have found that I get 97% to 103% of the advertised 6.0 Mbps download I am paying for. The upload advertised data rate of 512Kbps is not achieved. I usually get about 87.5% or 448Kbps. |
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NormanSPremium,MVM
join:2001-02-14
San Jose, CA
kudos:4 Reviews:
·SONIC.NET
·Pacific Bell - SBC
| reply to ipman
»AT&T Midwest/Ameritech FAQ »I never see the speed I ordered on speed tests. What a ripoff!!!!
Some DSL providers compensate for ATM overhead by "oversyncing" to bring the throughput up to the advertised speed. AT&T is not one of them.
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Norman
~Oh Lord, why have you come
~To Konnyu, with the Lion and the Drum |
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Reviews:
·DSL EXTREME
| reply to ipman
said by ipman:Is this what one should expect for traditional DSL service? Only 85-90% of the advertised bandwidth?
Yes. |
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ipman
join:2010-08-31
San Jose, CA | Thanks. I did have a small mix up on the DSL modem. I went back to check and it is indeed 768kbps/384kbps. It sucks to learn that only getting 85% of the advertised speed is the norm. I wonder how AT&T got away (from FCC) with it. |
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NormanSPremium,MVM
join:2001-02-14
San Jose, CA
kudos:4 Reviews:
·SONIC.NET
·Pacific Bell - SBC
| Not just AT&T: SBC before them, and probably 75% of all other U.S. DSL providers. As long as them modem shows sync at the advertised speed, the customer is getting what he paid for.
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Norman
~Oh Lord, why have you come
~To Konnyu, with the Lion and the Drum |
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Reviews:
·Millenicom
·AT&T Southeast
·Verizon Wireless..
| reply to ipman
Because they use the words "up to" when describing data rates and they warn that the subscriber may not see the advertised rate. Remember the old Cancer Treatment Centers of America ads that had the disclaimer type saying the happy results shown were not typical and that you should not expect the same result? The same disclaimer applies to ISPs. |
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| reply to NormanS
said by NormanS:Not just AT&T: SBC before them, and probably 75% of all other U.S. DSL providers. As long as them modem shows sync at the advertised speed, the customer is getting what he paid for.
The main source of overhead is that ADSL uses the Asynchronous Transfer Mode (ATM) protocol. This protocol breaks the data into 53-byte "cells", with each cell having 5 bytes of header. That is 5/53 = 9.4% overhead right there. |
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NormanSPremium,MVM
join:2001-02-14
San Jose, CA
kudos:4 Reviews:
·SONIC.NET
·Pacific Bell - SBC
| said by CharlesH1:The main source of overhead is that ADSL uses the Asynchronous Transfer Mode (ATM) protocol. This protocol breaks the data into 53-byte "cells", with each cell having 5 bytes of header. That is 5/53 = 9.4% overhead right there.
Do check out the link I posted. It does cover that; and more. The actual overhead an end user can expect is closer to 15% for reasons provided in that link.
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Norman
~Oh Lord, why have you come
~To Konnyu, with the Lion and the Drum |
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 DavidNow accepting new patientsPremium,VIP
join:2002-05-30
Granite City, IL
kudos:70
·AT&T Southwest
 ·DIRECTV
·AT&T Midwest
 ·Google Voice
| reply to ipman
The IPDSL dslams will correct this problem as most end users get maybe 5% max off by what the speeds they purchase. it's a lot closer than the 15-20% you can be off on speed tests.
Most IPDSL customers are just about at the exact speeds.
Most of the ATM is eliminated except between you and the IPDSLAM.
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If you have a topic in the direct forum please reply to it or a post of mine, I get a notification when you do this.
Koetting Ford, Granite City, illinois... YOU'RE FIRED!!
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1 edit | reply to NormanS
Agreeing with NormanS. Just pointing out that the big chunk is the ATM header overhead. As noted, by the time you add in the Ethernet headers, TCP/IP headers, and the PPOE header, you are up to the observed 15%.
Maybe some DSL providers sync at a higher rate to compensate for this overhead, but I think at&t is known to not be one of them. |
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 Wily_OnePremium
join:2002-11-24
San Jose, CA | reply to ipman
said by ipman:It sucks to learn that only getting 85% of the advertised speed is the norm. LOL, you don't remember the dial-up days, do you? 56K line and lucky to get over 28.8 - 31.2 was a rare gift! 
This is why all such services have the qualifier "up to". You can get "up to 768K". What you really get depends on line quality, the wiring inside your house, cosmic rays, etc. |
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DavidNow accepting new patientsPremium,VIP
join:2002-05-30
Granite City, IL
kudos:70 Reviews:
·AT&T Southwest
·DIRECTV
·AT&T Midwest
·Google Voice
| said by Wily_One:LOL, you don't remember the dial-up days, do you? 56K line and lucky to get over 28.8 - 31.2 was a rare gift!
I agree, I don't know how much money I kerplunked on dial up modems and just to find out I wouldn't get higher than 28.8kbps cause I was on a t1 fed pair gain switch.
When DSL made it to the apt. complex I was overjoyed when I was getting speeds of 140kbps. Made my 28.8 feel slow.
Today, I have a 6mbps connection at the house and it feels just right.
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If you have a topic in the direct forum please reply to it or a post of mine, I get a notification when you do this.
Koetting Ford, Granite City, illinois... YOU'RE FIRED!!
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