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Low Upload Speed but Moderate Download Speed

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Regular Visitor

Low Upload Speed but Moderate Download Speed

After upgrading my service too 600 Mbps download package I have notice extremely low upload speeds (generally <0.5 Mbps). This issue did not appear prior to this change and, in fact, did not start until after tech came by to "drop off equipment" (he did not drop off any equipment since I had already purchased and installed my own Motorola MB7621 which worked without issue). Download speeds have not been at the stated 600 Mbps at any point (typically ~200 - 250 Mbps). Checking my modem, I am seeing repeated instances of the following errors...

Warning (5)   B-INIT-RNG Failure - Retries exceeded;CM-MAC=00:40:36:65:9e:bd;CMTS-MAC=00:01:5c:96:a2:62;CM-QOS=1.0;CM-VER=3.0; 
Critical (3)   No Ranging Response received - T3 time-out;CM-MAC=00:40:36:65:9e:bd;CMTS-MAC=00:01:5c:96:a2:62;CM-QOS=1.0;CM-VER=3.0; 
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Regular Visitor

Re: Low Upload Speed but Moderate Download Speed

FYI, see channel info below...

   Upstream Bonded Channels
 

 

 
 

 


  
   Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)
1 Locked ATDMA 7 5120 23.0 47.3
2 Locked ATDMA 5 5120 36.1 47.8
3 Locked ATDMA 6 5120 29.6 47.5
4 Locked ATDMA 8 5120 16.5 46.8
5 Not Locked Unknown 0 0 0 0.0
6 Not Locked Unknown 0 0 0 0.0
7 Not Locked Unknown 0 0 0 0.0
8 Not Locked Unknown 0 0 0 0.0
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Expert

Re: Low Upload Speed but Moderate Download Speed

Also post the downstream channels.



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Regular Visitor

Re: Low Upload Speed but Moderate Download Speed

Download Channel Info...

 

  Downstream Bonded Channels
 

 

 
 

 


  
   Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB) Corrected Uncorrected
1 Locked QAM256 24 549.0 -6.1 40.4 0 0
2 Locked QAM256 25 555.0 -6.2 40.3 0 0
3 Locked QAM256 26 561.0 -6.1 40.5 0 0
4 Locked QAM256 27 567.0 -5.9 40.5 0 0
5 Locked QAM256 28 573.0 -6.0 40.3 0 0
6 Locked QAM256 29 579.0 -6.0 40.2 0 0
7 Locked QAM256 30 585.0 -6.1 40.3 0 0
8 Locked QAM256 31 591.0 -6.1 40.3 0 0
9 Locked QAM256 32 597.0 -6.2 40.4 0 0
10 Locked QAM256 33 603.0 -6.1 40.5 0 0
11 Locked QAM256 34 609.0 -6.2 40.5 0 0
12 Locked QAM256 35 615.0 -6.2 40.3 0 0
13 Locked QAM256 36 621.0 -6.3 40.3 0 0
14 Locked QAM256 37 627.0 -6.9 40.2 0 0
15 Locked QAM256 38 633.0 -6.8 40.2 0 0
16 Locked QAM256 39 639.0 -6.5 40.1 0 0
17 Locked QAM256 40 645.0 -6.7 41.7 0 0
18 Locked QAM256 41 651.0 -6.5 41.7 0 0
19 Locked QAM256 42 657.0 -6.5 42.0 0 0
20 Locked QAM256 43 663.0 -6.4 41.8 0 0
21 Locked QAM256 44 669.0 -6.6 41.8 0 0
22 Locked QAM256 45 675.0 -6.7 41.7 0 0
23 Locked QAM256 46 681.0 -6.8 41.6 0 0
24 Locked QAM256 47 687.0 -6.6 41.7 0 0
Total             0 0
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Expert

Re: Low Upload Speed but Moderate Download Speed

FWIW, this may not be the direct cause of your problem but it should be addressed nevertheless as it may be a problem just waiting to happen,

 

The downstream power is on the low side and it may be intermittently fluctuating even lowerer to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, and latency problems.

In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.



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Regular Visitor

Re: Low Upload Speed but Moderate Download Speed

Looking at my wiring, it appears that my cable is coming directly from the outside box. Could it be a modem problem? Thanks.
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Expert

Re: Low Upload Speed but Moderate Download Speed

It's more likely to be a line impairment problem.



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