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My 2048 Kb/S ADSL connection downloads at the expected download speed 220 KB/s , but it takes too long to get to that speed, in other words the top speed is fine but the acceleration is terrible. This is not a problem with large downloads because speed eventually gets to the maximum rate. The problem is with browsing or typing through SSH, because it depends on the initial speed of the packets which could be as slow as 3 KB/s! Latency is terrible and ISP cannot understand this. Although of acceptable values for line attenuation (14.0) and SNR Margin (32.4)

No proxies used...

I cannot find similar answers on Google. Maybe I cannot descibe the problem? What is the term defining this problem (like Latency, Packets loss) I do not know. And what can I tell my ISP?

EDIT: Here is the output of traceroute google.com

laptop:~$ traceroute google.com traceroute to google.com (173.194.38.102), 30 hops max, 60 byte packets
1 192.168.1.254 (192.168.1.254) 5.538 ms 5.772 ms 12.180 ms
2 * KHANKA-R01C-C-EG (163.121.170.229) 38.951 ms 53.544 ms
3 host-163.121.211.134.tedata.net (163.121.211.134) 1022.649 ms 1157.199 ms 1171.533 ms
4 host-163.121.211.134.tedata.net (163.121.211.134) 1368.481 ms 1392.954 ms 1456.449 ms
5 host-163.121.211.125.tedata.net (163.121.211.125) 1483.733 ms 1485.976 ms 1559.233 ms
6 10.42.0.3 (10.42.0.3) 2137.709 ms 984.750 ms 1311.599 ms
7 10.32.8.107 (10.32.8.107) 1184.654 ms 1188.532 ms 1529.284 ms
8 host-163.121.215.194.tedata.net (163.121.215.194) 1537.709 ms host-163.121.209.170.tedata.net (163.121.209.170) 1525.038 ms host-163.121.215.194.tedata.net (163.121.215.194) 1784.301 ms
9 72.14.212.13 (72.14.212.13) 1779.373 ms 1863.601 ms 2083.181 ms
10 * 209.85.252.194 (209.85.252.194) 2598.120 ms 209.85.252.36 (209.85.252.36) 2643.383 ms
11 216.239.43.42 (216.239.43.42) 2670.846 ms 2674.115 ms 3114.124 ms
12 216.239.43.4 (216.239.43.4) 2970.444 ms 2983.826 ms 216.239.46.218 (216.239.46.218) 1316.574 ms
13 209.85.249.11 (209.85.249.11) 1287.924 ms 1309.304 ms 72.14.239.93 (72.14.239.93) 1309.548 ms
14 216.239.48.69 (216.239.48.69) 1327.934 ms 1333.812 ms 1418.224 ms
15 66.249.94.24 (66.249.94.24) 1426.165 ms 1435.831 ms 66.249.94.22 (66.249.94.22) 1434.125 ms
16 72.14.239.83 (72.14.239.83) 1642.336 ms 1647.606 ms 1663.440 ms
17 64.233.174.177 (64.233.174.177) 1767.621 ms 1806.839 ms *
18 209.85.255.37 (209.85.255.37) 1554.591 ms 1483.272 ms 1498.464 ms
19 209.85.251.239 (209.85.251.239) 1301.597 ms 1308.220 ms 1319.829 ms
20 nrt19s18-in-f6.1e100.net (173.194.38.102) 1321.308 ms 1323.904 ms 1338.072 ms

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1  
What is your ping delay to some major sites ? –  Gregory MOUSSAT Apr 24 '12 at 0:28
    
Google and yahoo average 1000 ms –  rahmanisback Apr 24 '12 at 0:32
1  
Is this a home environment, or are you managing a company network using a DSL uplink? –  voretaq7 Apr 24 '12 at 0:44
1  
Your problem clearly comes from your 3rd hop. You can't do anything about that, except either change ISP (only good way I think) or try to convince them to fix their network. But if they didn't detected the problem themselve, this is because they are not a good provider at all. –  Gregory MOUSSAT Apr 24 '12 at 23:41
1  
The odd thing is, when I trace that same path (but in the other direction), I get normal pings. I see about 5ms on that hop. –  David Schwartz Apr 25 '12 at 1:01
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2 Answers

up vote 3 down vote accepted

With the information present in your question, there's really no way to help you. In fact, if that's all of the information that you've gathered, you can't even help yourself. There are three rules to troubleshooting:

  1. Gather Data
  2. Gather Data
  3. Gather Data

There might be a few other rules, but they all bow in subservience to the first three. You need to be gathering as much information at the demarc point as possible. Whatever your CPE is (in your case, a DSL modem) you need to be picking as much information off of it as is possible. Poll it for SNMP information, get syslog out of it, check its manual for any special APIs, the whole nine yards.

You need to also take timed interval tests concerning latency, bandwidth, packet loss, etc. Set up SmokePing. Use a scheduled iperf script and record the pertinent information. The onus is always upon you, the customer, to prove that the ISP is the problem. You and your equipment are presumed guilty until otherwise discovered. Furthermore, the evidence that you supply to prove your innocence needs to be in triplicate with shiny graphs and perhaps intro music.

It could be as simple as some wonky congestion control (Slow-Start comes to mind). It could be bad lines to the DSLAM. It could be any number of things, but you can't know any of the possibilities until you've armed yourself with as much data from your end of the line as is humanly possible.

TL;DR

Go forth and gather data.

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1  
Say "Gather data" ten times in a row and see if it doesn't sound like the weirdest thing when you're done. –  Wesley Apr 24 '12 at 0:16
    
+1 for gathering data. Also gather some knowledge about how the internet works: Slow Start and Why high bandwidth delay product links are slow –  voretaq7 Apr 24 '12 at 0:46
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If you have bad latency there will probably be nothing you can do for ssh since speed is typically not needed for ssh, but interactivity is.

For web browsing, if you can create an established connection to a proxy where latency isn't as bad, it may improve ( if Slow-Start is the source of the issue ). At least your connection to the proxy will as fast as it can go, and you can get all your web requests queued up on the other side.

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