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mrcutter

join:2012-12-29
Cleveland, OH
reply to mrcutter

Re: [Line Problem] Bizzare DSL problem - some sites load, others

Just did a little searching - am I correct that the 6dB downstream noise margin is "really bad" and that the 17.4dB of output power means that the DSLAM is effectively "screaming" to try and hit my modem?



d_l
Barsoom
Premium,MVM
join:2002-12-08
Reno, NV
kudos:7

said by mrcutter:

Just did a little searching - am I correct that the 6dB downstream noise margin is "really bad" and that the 17.4dB of output power means that the DSLAM is effectively "screaming" to try and hit my modem?

Correct, but that shouldn't cause site loading problems UNLESS you were having heavy CRC errors. Sites that have a lot of advertisements pulling in from advertising servers around the country could have troubles loading.

Alternatively your traffic to the problem sites might be having problem with the servers and backbone in between.

Ping problems would tend to favor the latter suggestion. Tiny pings usually aren't affected by CRC errors. They slip through.

Try tracerts to the sites and compare the routs of the good with the bad.
--
TCE Weather -- Mt. Rose Cam

mrcutter

join:2012-12-29
Cleveland, OH

DL - when I look at my details log for the broadband connection I see zeros across the board and no indication of a real communication problem. I am increasingly convinced there is a problem with AT&T's network in Cleveland, and it's an insidious one at that.

I use the term "insidious" because I think a lot of people are used to the network status as a one or a zero - it works or it doesn't. When some sites work and others don't, it gets put into an odd area in between. Some users may, by luck, never see this problem, and others may see if all the time.

I am hoping to gather more information, then make my case to AT&T over in the direct forums. I appreciate the complexity of networking, and want to provide time to gather information that may be able to assist AT&T's technicians and engineers.



nwrickert
sand groper
Premium,MVM
join:2004-09-04
Geneva, IL
kudos:7
Reviews:
·AT&T U-Verse
reply to mrcutter

said by mrcutter:

Just did a little searching - am I correct that the 6dB downstream noise margin is "really bad" and that the 17.4dB of output power means that the DSLAM is effectively "screaming" to try and hit my modem?

It's been a while since I was on regular ADSL.

6dB s/n is usable.

As I recall, I had an attenuation around 56dB, so I was near the end of the line. The output power was usually in the 12-14 range. So, yes, the high output power in your case hints at a noisy line and an attempt to drown out the noise.
--
AT&T Uverse; Zyxel NBG334W router (behind the 2wire gateway); openSuSE 12.2; firefox 17.0