mrenglishman
join:2007-04-29
Greece
| Hi,
First post in here and naturally, I am starting with a problem with which I need you help =). I will try to make my post as detailed as possible. So here we go
I have a US Robotics 9108A router and a 4mbit dsl line. From the moment I was connected with my ISP, I have been facing the following problem: When I am downloading something (e.g. a file from an FTP or HTTP - let's say Rapidshare) at the maximum speed that my connection can provide -that is around 410-420kb/s- the router almost EVERY time loses the synchronization with the DSLAM and either tries to resync or remains "dead" until I phone my ISP's support and get them to fix the problem from their side.
The above problem does not appear when I am just browsing the web but only when I am "pushing" the connection to it's limits. Please note that I use a download manager (Flashget) which opens multiple connections when I'm downloading something.
The first thing that came to my mind is that there is too much noise in my DSL line. Indeed, the USR9108A stats say that the Attenuation is at 54/32.4 dB (Downstream/Upstream respectively) and the Signal-to-Noise Ratio (SNR) is at 16.6/9.7 dB(Downstream/Upstream respectively). As you can see, those numbers are disappointing but not high enough to fully justify the dropping of the connection every time. Furthermore, if the problem solely relied on the line noise, wouldn't the synchronization problem appear in any case and not only when I'm downloading at high speeds?
Now let's get to the most interesting and strange part: When I tried a DIFFERENT router (a SpeedStream 4200) on the SAME dsl line, the Attenuation and SNR levels -as reported by the router's config pages- dropped significantly! The Attenuation was now at 40.1/25.3 dB(Down/Up) and the SNR at 10.1/7.3 dB (Down/Up). Remember that this router is on the SAME line as the US Robotics was previously! And of course all stability problems disappeared.
Please note that both routers were working in ADSL2+ mode and trying to change the modulation to G.DMT or ADSL2 on the USRobotics did not result to any significant difference (a minor +-1dB change occurred between the different modulations).
So, what do you think is going on? Is there a problem with the US Robotics router? Do you think it can be fixed somehow or should I exchange it for a new one since it is covered by the guarantee? I do not want to bridge the two routers (use the SpeedStream for the connection and the USR for the routing).
Thank you in advance for your time and your help. It's great to be here.
Best regards,
Constantinos |
