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Author Topic: Upstream - why so bad / good  (Read 2210 times)

Weaver

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  • Retd s/w dev; A&A; 4x7km ADSL2 lines; Firebrick
Upstream - why so bad / good
« on: February 01, 2018, 03:33:42 AM »

Upstream

am wondering why my lines’ upstream performance is so bad or good?

I has been like this for a couple of years
   line a.1   560k - 570k
   line a.3   440k - 450k
   line a.4   450k - 500k

( line 4 was usually around the 500k mark, recently dropped by 45k suddenly which is unusual.)

a.1 and a.3 share the same drop cable, a.4 is on its own.

Line 1 is the mystery - why has it so good, it has always been 22-29% better than line 3 _and_ usually 10% better than line 4?

Line a.3 why so bad relatively- so much worse usually than line 4 and, leaving aside the recent blip, a lot worse than line a.4 which is usually around ~500k as opposed to line a.3’s constant 440k-450k.

I wonder what I can do to improve line a.3?
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kitz

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Re: Upstream - why so bad / good
« Reply #1 on: February 03, 2018, 12:59:41 PM »

a.3 - could it be crosstalk from a.1 with them being in the same pair?   Not sure  :-\

The sudden drop on the upstream on a.4 could be an emerging HR fault. 
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Weaver

  • Senior Kitizen
  • ******
  • Posts: 11459
  • Retd s/w dev; A&A; 4x7km ADSL2 lines; Firebrick
Re: Upstream - why so bad / good
« Reply #2 on: August 02, 2018, 03:40:21 AM »

Since changing to the ZyXEL VMG1312-B10A modems, my upstream speeds have been
line cwcc@a.1 500k
line cwcc@a.3 440k
line cwcc@a.4 440k
so significantly worse than with the DLink modems, which is really bad news.

I took a look at the bits-per-bin loading on the upstream of lines cwcc@a.1 vs cwcc@a.3m shown below. (These two lines are the two pairs within one drop cable.)

Code: [Select]
Bits per bin upstream of modem on line cwcc@a.1 vs line cwcc@a.3
bin# bits freq    bits
0 0 0.0000  0
1 0 4.3125  0
2 0 8.6250  0
3 0 12.9375  0
4 0 17.2500  0
5 0 21.5625  0
6 0 25.8750  0
7 8 30.1875  8
8 9 34.5000  9
9 10 38.8125  9
10 10 43.1250  9
11 10 47.4375  9
12 9 51.7500  9
13 9 56.0625  8
14 9 60.3750  8
15 9 64.6875  8
16 8 69.0000  7
17 8 73.3125  7
18 8 77.6250  7
19 8 81.9375  6
20 7 86.2500  6
21 7 90.5625  6
22 7 94.8750  6
23 7 99.1875  6
24 7 103.5000 5
25 6 107.8125 5
26 6 112.1250 5
27 6 116.4375 5
28 6 120.7500 4
29 5 125.0625 4
30 5 129.3750 4
31 0 133.6875 0
32 0 138.0000 0
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