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Help with Erratic Gigabit speeds with SB8200

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Official Employee

Re: Help with Erratic Gigabit speeds with SB8200

 

phistyle, let's take a look at your speed concerns. Please send me a private message with your full name, address and phone number tied to your residential services for help. Just click my name and then click private message me.

Diamond Problem Solver

Re: Help with Erratic Gigabit speeds with SB8200


@phistyle wrote:

He said both send receive lights are supposed to be blue, but what I've read online, only the receive "downstream" light is supposed to be blue and the send light is supposed to be green.   


You are correct because Comcast doesn't yet support DOCSIS 3.1 for the upstream / return path. 

 

https://www.midco.com/contentassets/21f126b6721648ae910ae0af1328e9ff/arris-sb8200-user-guide_2017-08...

Frequent Visitor

Re: Help with Erratic Gigabit speeds with SB8200

Update:  tech came by and said it is due to a "bad modem".  He said both send receive lights are supposed to be blue, but what I've read online, only the receive "downstream" light is supposed to be blue and the send light is supposed to be green.  He said my line was fine, but I don't know what to believe so I have another sb8200 modem coming in today and we'll see if it's the modem that's the problem.  These techs that they send out don't really seem like they know what they are talking about sometimes. 

Expert

Re: Help with Erratic Gigabit speeds with SB8200

Hi @phistyle,

Your upstream power levels are pretty low. There isn't anything you can do about it, a premise tech will have to get the repair process started by escalating the issue to the proper department. You are on the right path to get this fixed. Please keep us updated! 

 

PS: After it is fixed you can ask for a credit for the time when you first reported the issue until it is resolved. 


I am not a Comcast employee, just a moderator. Pls observe Wheaton's Law.
Frequent Visitor

Help with Erratic Gigabit speeds with SB8200

I just upgraded to gigabit in Houston, TX and bought a new Arris SB8200 and having been getting inconsistent speeds.  I used a bunch of different speed test sites and the numbers are all over the place.  The only site that I was able to get 900 Mbps was the comcast speed test site.  Other sites, i would get 700 Mbps or sometimes even 200 Mbps.  Not sure if this is normal either, but everytime I reset my modem, I get like low 20 Mbps that last like 10 - 15 min before it goes up.  I never had that problems on other speed tiers when reseting my modem.  I have a tech coming out on Tuesday to check my line, but I want to get some other opinions on my status.  I'm connected to a router, but speeds were the same even directly connected to the modem. 

 

Connection

The status listed show the connection state of the cable modem. They are used by your service provider to evaluate the operation of the cable modem.

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 657000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Configuration File OK  
Security Enabled BPI+
DOCSIS Network Access Enabled Allowed  

 
Downstream Bonded Channels
Channel ID Lock Status Modulation Frequency Power SNR/MER Corrected Uncorrectables
29 Locked QAM256 657000000 Hz 2.9 dBmV 40.2 dB 0 0
1 Locked QAM256 489000000 Hz 2.1 dBmV 40.0 dB 0 0
2 Locked QAM256 495000000 Hz 3.5 dBmV 40.7 dB 0 0
3 Locked QAM256 501000000 Hz 4.0 dBmV 40.6 dB 0 0
4 Locked QAM256 507000000 Hz 4.2 dBmV 40.8 dB 0 0
5 Locked QAM256 513000000 Hz 4.3 dBmV 40.8 dB 0 0
6 Locked QAM256 519000000 Hz 4.2 dBmV 40.9 dB 0 0
7 Locked QAM256 525000000 Hz 4.1 dBmV 40.8 dB 0 0
8 Locked QAM256 531000000 Hz 3.8 dBmV 40.7 dB 0 0
9 Locked QAM256 537000000 Hz 3.8 dBmV 40.6 dB 0 0
10 Locked QAM256 543000000 Hz 3.5 dBmV 40.1 dB 0 0
11 Locked QAM256 549000000 Hz 3.6 dBmV 40.4 dB 0 0
12 Locked QAM256 555000000 Hz 3.7 dBmV 40.6 dB 0 0
13 Locked QAM256 561000000 Hz 3.9 dBmV 40.6 dB 0 0
14 Locked QAM256 567000000 Hz 3.9 dBmV 40.4 dB 0 0
15 Locked QAM256 573000000 Hz 4.0 dBmV 40.7 dB 0 0
16 Locked QAM256 579000000 Hz 3.9 dBmV 40.5 dB 0 0
17 Locked QAM256 585000000 Hz 4.1 dBmV 40.5 dB 0 0
18 Locked QAM256 591000000 Hz 3.8 dBmV 40.4 dB 0 0
19 Locked QAM256 597000000 Hz 3.8 dBmV 40.4 dB 0 0
20 Locked QAM256 603000000 Hz 3.6 dBmV 40.1 dB 0 0
21 Locked QAM256 609000000 Hz 3.5 dBmV 40.3 dB 0 0
22 Locked QAM256 615000000 Hz 3.5 dBmV 40.4 dB 0 0
23 Locked QAM256 621000000 Hz 3.4 dBmV 40.2 dB 0 0
24 Locked QAM256 627000000 Hz 3.4 dBmV 40.3 dB 0 0
25 Locked QAM256 633000000 Hz 3.2 dBmV 39.9 dB 0 0
26 Locked QAM256 639000000 Hz 3.3 dBmV 40.1 dB 0 0
27 Locked QAM256 645000000 Hz 3.2 dBmV 40.2 dB 0 0
28 Locked QAM256 651000000 Hz 3.1 dBmV 40.3 dB 0 0
30 Locked QAM256 663000000 Hz 2.8 dBmV 40.0 dB 0 0
31 Locked QAM256 669000000 Hz 2.8 dBmV 39.9 dB 0 0
159 Locked Other 732000000 Hz 7.1 dBmV 36.5 dB 162231 0

 
Upstream Bonded Channels
Channel Channel ID Lock Status US Channel Type Frequency Width Power
1 7 Locked SC-QAM 23000000 Hz 6400000 Hz 28.3 dBmV
2 5 Locked SC-QAM 36100000 Hz 6400000 Hz 28.3 dBmV
3 6 Locked SC-QAM 29600000 Hz 6400000 Hz 28.8 dBmV
4 8 Locked SC-QAM 16500000 Hz 6400000 Hz 27.8 dBmV

 

Event Log

The table below contains the log of events that the SB8200 has detected. This log can be important to the service provider to help diagnose and correct problems, if any should occur.

Time Priority Description
6-14-2018, 0:29:56 Warning(5) "Dynamic Range Window violation"
1-1-1970, 0:0:42 Notice(6) "Honoring MDD; IP provisioning mode = IPv6"
1-1-1970, 0:0:33 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=3c:04:61:ff:4b:d1;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
6-12-2018, 18:26:13 Critical(3) "Resetting the cable modem due to docsDevResetNow"
1-1-1970, 0:0:33 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=3c:04:61:ff:4b:d1;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
6-12-2018, 18:9:43 Critical(3) "Resetting the cable modem due to docsDevResetNow"
1-1-1970, 0:0:33 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=3c:04:61:ff:4b:d1;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
6-12-2018, 18:2:36 Critical(3) "Resetting the cable modem due to docsDevResetNow"
1-1-1970, 0:0:33 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=3c:04:61:ff:4b:d1;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
1-1-1970, 0:0:29 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=3c:04:61:ff:4b:d1;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"
1-1-1970, 0:0:32 Critical(3) "Telnet user logged in from IP address 192.168.100.10."
1-1-1970, 0:0:29 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=3c:04:61:ff:4b:d1;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;"