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Arbies
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16 Messages

Wed, Oct 14, 2020 2:00 PM

Troubleshooting 1G+. Sanity check on signal strength.

This started when I tried to enable LAGG on my modem. I was able to enable it and get it communicating but could never get an IPv6 address assigned. Obviously not a big deal as service is working and decent speeds, but I have heard rumors and I am chasing the 20% overprovision 1.2Gig here I come.

Tried all kinds of combinations of setting and configurations. I have found that LAGG enabled with only one Ethernet cable plugged in or LAGG disabled both work fine.
If I plug in the second cable after getting fully connected I keep the IPv6 address, but if I reboot or release/renew it will not get the IPv6 address or in some cases any address. So I left the second cable out for now in case of a power or network outage.

IPv6 should not be a big issue, and the internet does work. But, some webpages have to be reloaded a few times and a lot of smart tv apps do not work. As soon as I get an IPv6 address everything is fine.

Saw this post, someone at the very end claimed the same, but it was not the focus of the thread so looks to be unanswered. https://forums.xfinity.com/t5/Your-Home-Network/Link-Aggregation-SB8200/td-p/3348468

My setup
I think there is a comcast owned repeater in my yard (small green cylinder). Coax cable run under and above ground through the yard straight shot but rugged terrain, maybe a few hundred feet. Coax pops out on the side of the house. Service loop and into a ground block. Coax enters the house 20ish feet. Passes through a Belkin power strip with surge protection for coax. Coax enters a Extreme 5 port amplifier. From an amped output into an MB8600 modem(self-owned).
Ethernet out of the modem 6 feet to a PFSense (self-owned) Cat7 cable. PFSense has 10Gig Ethernet ports, the WAN port negotiates to 1Gig
Ill stop there as I know the rest is my network and is highly dependent on my equipment.

Running a SpeedTest CLI on my PFSense I get between 300 and 700, I have see as high as low 800s.

Selecting best server based on ping...

Hosted by Windstream (Atlanta, GA) [29.44 km]: 13.277 ms

Testing download speed................................................................................

Download: 693.36 Mbit/s

Testing upload speed......................................................................................................

Upload: 32.69 Mbit/s

 

Looking into Modem signal levels I get the below, but I am not sure what I am looking at. I have called the 1800 before but hit a hard wall when they see I own my modem/router. I have not called specifically about the this LAGG issue. Hoping for better liuck here.

I did bypass the surge protector and amplifier and got -4db across the board on the downstream so the amp seems to working as advertised.

I have not tried bypassing my home completely and going straight to the service loop, but might try that this weekend.

Can someone look and tell me if I am on the right path here or if the signal is good and I need to look at the other side (my network) of the modem.

 

Thanks

Arbies_0-1602712478894.png

 

Responses

Arbies

Frequent Visitor

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16 Messages

7 m ago

I have been googling around and found a handfull of refernces on the r/Comcast/Xfinity reddit. Specifically around the MB8600 and the "Configuration File". Mine is currently blank. In the references I found it was either blank or stuck on a lower teir after upgrade.

Arbies_0-1602898153860.png

 

I had cut it off in my screenshot previously b/c I was focused on signal strength. (Which I still think is a little off).
One post recomended
""factory default" stage and will force any new firmware updates along with forcing a new boot-file to be loaded. If the billing codes are correct, you should get the" file.
I will also try that this weekend.

CCAndrew

Diamond Problem Solver

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25.9K Messages

7 m ago

You should also be focused on signal strength of the upstream. All four are too high and out of spec. Any splitters that you can remove to help lower that?
Arbies

Frequent Visitor

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16 Messages

7 m ago

I'll plug the modem straight into the service loop outside my house this weekend and see if that helps the upstream.

CCAndrew

Diamond Problem Solver

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25.9K Messages

7 m ago

You didn’t answer the splitters question. What’s your cable setup?
Arbies

Frequent Visitor

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16 Messages

7 m ago

My current set up is in the original post. The one splitter/amp has a forward gain of 4db and a reverse gain of -11db.

Arbies

Frequent Visitor

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16 Messages

7 m ago

Alright, spent some time on it this morning. I took the modem and an extention cord and moved from place to place. I had a laptop with a NIC that supports 1G hooked directly to the modem.

ChannelModulationChannel IDFreq. (MHz)Pwr (dBmV)At the Service loop outside my houseAt the input to the surge protector
At the input to the Amp/Splitter
 "-3.5db Voip/Data Output""+4db Outout"
1OFDM PLC193690 -3.8-6.6-6.8 -10.7-3.1
2QAM2561465 -4.7-6.6-6.9 -10.3-3.1
3QAM2562471 -4.6-6.6-6.9 -10.3-2.9
4QAM2563477 -4.1-6.1-6.4 -9.8-2.3
5QAM2564483 -4.1-6.1-6.4 -9.8-2
6QAM2565489 -3.9-5.9-6.3 -9.7-1.7
7QAM2566495 -4.3-6.3-6.6 -10.1-1.9
8QAM2567501 -4.2-6.2-6.5 -10-1.7
9QAM2568507 -4.3-6.4-6.6 -10.2-1.9
10QAM2569513 -4.3-6.3-6.6 -10.2-1.9
11QAM25610519 -4.6-6.6-6.9 -10.5-2.2
12QAM25611525 -4.6-6.7-7.1 -10.6-2.4
13QAM25612531 -4.5-6.6-7.1 -10.6-2.3
14QAM25613537 -4-6.3-6.7 -10.1-2
15QAM25614543 -3.8-5.9-6.5 -10-2
16QAM25615555 -3.5-5.6-5.9 -9.9-2.1
17QAM25616561 -3.6-5.7-6 -10-2.2
18QAM25617567 -3.6-5.8-6 -10-2.5
19QAM25618573 -3.8-6-6.2 -10.2-2.8
20QAM25619579 -4-6.3-6.5 -10.1-2.9
21QAM25620585 -4.2-6.4-6.7 -10.3-3.2
22QAM25621591 -4-6.4-6.8 -10.2-3
23QAM25622597 -3.9-6.4-6.9 -10.3-3.1
24QAM25623603 -3.6-6-6.5 -9.9-2.5
25QAM25624609 -3.6-6-6.5 -9.9-2.4
26QAM25625615 -3.1-5.5-5.9 -9.4-1.9
27QAM25626621 -3-5.6-5.8 -9.3-1.5
28QAM25627627 -3.3-5.8-6 -9.6-1.8
29QAM25628633 -3.8-6.3-6.4 -10.2-2.1
30QAM25629639 -3.8-6.3-6.5 -10.2-2
31QAM25630645 -4-6.4-6.8 -10.6-2.3
32QAM25631651 -4.3-7-7.5 -11.1-2.5
33QAM25632657 -4.8-7.4-8 -11.5-3.1
    AVERAGE-3.990909091-6.245454545-6.581818182 -10.16969697-2.342424242
    MIN-4.8-7.4-8 -11.5-3.2
    MAX-3-5.5-5.8 -9.3-1.5
           
1SC-QAM135.6  4344 47.353
2SC-QAM229.2  43.843.8 46.853.8
3SC-QAM322.8  42.842.8 46.552.8
4SC-QAM416  42.342.3 4652.3
    AVERAGEoops, missed these42.97543.225 46.6552.975



Arbies

Frequent Visitor

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16 Messages

7 m ago

I did a factory reset of my modem (holding the reset button and then powering off for 5 min). After powering it back on ti took longer than usual to boot and the LAGG: Enabled was disabled again. So I assume the factory reset went well.
After booting, the configuration/boot file is still blank.

Configuration FileOK 
 

 

 

I spent some time on the phone with customer service.
I was told there is an outage in my area (odd b/c my Internet is working fine) and that due to the outage the system would not let him run any remote diagnostics.
I mentioned the missing config file, after a brief hold, I was told all of my equipment is provisioned correctly. I asked how he checked since the outage was preventing remote diagnostics, but he did not give me a response.
He did tell me that he would put in a level 2 ticket. I am not sure if I am expecting to get a call or if they will look into without my assistance.

 

I might try reddit next, seems as they have helped people with their missing config file in the past. Most threads end up with 'Please send us a mod mail and we will try and help resolve the issue', then the thread gets locked and no solution is posted.

EG

Expert

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86.5K Messages

7 m ago

FWIW, the config file indicator is not "blank". It says "ok" which means that a config file is indeed present / loaded in. It's only "blank" in the sense that it doesn't reveal the naming convention of the file. Some models of modems do, some do not. It couldn't be online at all without there being a config file installed.

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!tick
Arbies

Frequent Visitor

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16 Messages

7 m ago

Understood. Maybe I am chasing a ghost there, but it would give me the warm and fuzzies to see something like
d11_m_mb8600_gigabit_c01.cm

as I have seen screenshots of others that did have a file name and not a blank.

EG

Expert

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86.5K Messages

7 m ago


@Arbies wrote:

Understood. Maybe I am chasing a ghost there, but it would give me the warm and fuzzies to see something like
d11_m_mb8600_gigabit_c01.cm

 


Understood !

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!tick
Arbies

Frequent Visitor

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16 Messages

7 m ago

Hey @CC Do the numbers shed any light?
Dose the -11db reverse gain in the splitter/amp mean that on the street side (Comcast) will be seeing ~53-11 = ~42db? That would be more inline witht the modem connected to the line with no splitters/amps.  So even though it seems high if you account for the 11db drop it would be within spec? Still trying to interperate these numbers.
I am guessing that at the recieveing end Comcast wants a specific range and if its to high/low it can negoatiateg with my modem (as lng as the modem can support the request). Further my modem can't negotiate the other way b/c that change in signal would affect my neighbors. Trying to learn.

Thanks,

Arbies

Frequent Visitor

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16 Messages

6 m ago

Little update: Got a hold of a mod on the reddit channel

He was able to poll the diagnostics from your MB8600 and did see the proper bootfile in place.
I still do not see anything in the Comment filed but as was said here that might not be a problem as its just a comment.

 

Note: Logging into my modem asked me to set a new admin password and the GUI has changed (menus on the left not top), from some googling (https://www.dslreports.com/forum/r32907776-MB8600-New-software-GUI) this seems to be due to a software upgrade to 8600-19.3.15. So i am guessing he did something to push that update.

Did a little testing, using pfsense and running the speedtest.net command line interface tool, I am getting high 700s -low 800s consistently
Download: 801.84 Mbit/s
Uploads typically always hitting 40s
Upload: 41.65 Mbit/s

 

I am still seeing the same isue with LAGG. The modem and pfsense are both set up for LAGG but I just have 1 cable plugged in for now.

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