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Low download speed with Docsis 3.1

Frequent Visitor

Low download speed with Docsis 3.1

I subscribed to docsis 3.1 1 month ago in Miami, FL. I have been unable to achieve download speeds above 450 Mbits. COmcast does not know what is going on and has a maintenence ticket open for 3 weeks now. It seems that comcast cannot support a service it offers to clients.

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Frequent Visitor

Re: Low download speed with Docsis 3.1

Anyone in Miami able to get 990+ Mbits download with Arris SB8200?

Problem Solver

Re: Low download speed with Docsis 3.1

How do your signal stats look like? You can get to them by going to http://192.168.100.1
New Poster

Re: Low download speed with Docsis 3.1

Having similar issues:

 

Was on prior XFinity eMTA/GW with Blast consistently reliable and speed consistant at 180Mb/sec down, and 12Mb/up. Today finally (after talking to no less tha 12 folks at ComcastSmiley Happy got the new ARRIS SB8200 modem installed and operational. However, only one blue light is solid (downstream), and the upstream is green solid light. What is odd is the upstream speed has gone from 12Mb to 41Mb/sec - yet the light indicates the upstream never changed to DOCSIS 3.1 so I don't understand that at all. The problem is actually on the downstream side. I cannot get a speed test past 500. The results of tests tonight have been all over the place:

 

Test cases: direct connection to CAT6 ports via Cisco Layer 2 switch, static IP, no routing. High end PC. I work in IT and have worked on networks for past 25 years. I have a mini-datacenter in my basement with 100Gb ethernet, 10Gb ethernet, and 1Gb/100Mb ethernet, and have tested the PC I am using up to 1Gb internally and the PC is capable of driving that much data off of the PCIe SSD.

 

Tests run approximately ever 15-20 minutes (not on the dot though):

 

Test 1: 554Mb/43Mb  (some spikes in the tool to 750ish) - begin around 10:30PM

Test 2: 583Mb/38Mb  (some spikes in the tool to high 600's) (about an hour past test 1)

Test 3: 378Mb/43Mb  (no spikes apparent)

Test 4: 160Mb/37Mb  (no spikes apparent)

Test 5:  69Mb/35Mb   (no spikes apparent)

Test 6:  73Mb/38Mb   (no spikes apparent)

Test 7:  60Mb/41Mb   (no spikes apparent)

Test 8:  65Mb/39Mb  (no spikes apparent)

Test 9:  61Mb/44Mb   (no spikes apparent)

Test 10: 59Mb/41Mb  (no spikes apparent)

Test 11: 183Mb/45Mb  (no spikes apparrent) (at 2:00AM)

 

These tests are all over the place, and Blast never did this. Blast always was within 180-210Mb 100% of the time. The upstream is solid as a rock (despite not having the blue light on for the upstream side).

 

If anyone has any ideas (especially the Comcast Engineers) on how to fix this and a) get closer to 1Gb, and b) get more consistency in the speed - especially as you can see during the tests, I dropped to around 60Mb for a significant period of time. 

 

Here is the status of the modem:

 

21 Locked QAM256 663000000 Hz 2.9 dBmV 38.7 dB 0 0
1 Locked QAM256 543000000 Hz 3.5 dBmV 39.6 dB 0 0
2 Locked QAM256 549000000 Hz 3.2 dBmV 39.7 dB 0 0
3 Locked QAM256 555000000 Hz 2.9 dBmV 39.4 dB 0 0
4 Locked QAM256 561000000 Hz 2.9 dBmV 39.3 dB 0 0
5 Locked QAM256 567000000 Hz 2.9 dBmV 39.2 dB 0 0
6 Locked QAM256 573000000 Hz 2.8 dBmV 39.2 dB 0 0
7 Locked QAM256 579000000 Hz 3.0 dBmV 39.2 dB 0 0
8 Locked QAM256 585000000 Hz 3.0 dBmV 39.2 dB 0 0
9 Locked QAM256 591000000 Hz 3.0 dBmV 39.1 dB 0 0
10 Locked QAM256 597000000 Hz 3.2 dBmV 39.2 dB 0 0
11 Locked QAM256 603000000 Hz 3.1 dBmV 39.0 dB 0 0
12 Locked QAM256 609000000 Hz 3.1 dBmV 38.9 dB 0 0
13 Locked QAM256 615000000 Hz 3.0 dBmV 38.9 dB 0 0
14 Locked QAM256 621000000 Hz 2.9 dBmV 38.8 dB 0 0
15 Locked QAM256 627000000 Hz 2.8 dBmV 38.8 dB 0 0
16 Locked QAM256 633000000 Hz 2.9 dBmV 38.8 dB 0 0
17 Locked QAM256 639000000 Hz 2.7 dBmV 38.7 dB 0 0
18 Locked QAM256 645000000 Hz 2.6 dBmV 38.6 dB 0 0
19 Locked QAM256 651000000 Hz 2.5 dBmV 38.6 dB 0 0
20 Locked QAM256 657000000 Hz 2.8 dBmV 38.8 dB 0 0
22 Locked QAM256 669000000 Hz 2.9 dBmV 38.6 dB 0 0
23 Locked QAM256 675000000 Hz 2.6 dBmV 38.6 dB 0 0
24 Locked QAM256 681000000 Hz 3.0 dBmV 38.8 dB 0 0
159 Locked Other 702000000 Hz 5.5 dBmV 38.2 dB 74 0

 

 
Upstream Bonded Channels
Channel Channel ID Lock Status US Channel Type Frequency Width Power
1 1 Locked SC-QAM 36500000 Hz 6400000 Hz 37.8 dBmV
2 2 Locked SC-QAM 30100000 Hz 6400000 Hz 38.3 dBmV
3 3 Locked SC-QAM 23700000 Hz 6400000 Hz 37.8 dBmV
4 4 Locked SC-QAM 17300000 Hz 6400000 Hz 38.3 dBmV

 

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