bluesrhythm's profile

Contributor

 • 

15 Messages

Mon, Aug 3, 2020 10:00 AM

Re: daily restart of modem

I have a similar circumstance - started a few weeks ago when I upgraded to 1Gbps plan (our promotional plan expired and this was a nearly cost-equivilant switch) and a new Xfinity-owned XB6 gateway (hw details below).  After install we couldn't get anywhere near the plan speeds (we'd get about 30Mbps down, 40Mbps up), had many chats with tech support, and eventually after they pushed a refresh started getting 300Mbps down consistently, and up to 700Mbps down (all speeds measured via direct ethernet connection to the gateway).  But at that point, started seeing intermittent disconnects throughout the day. 

 

Tech came out, verified in-house wiring, modem install itself, and the wire to the pole are all fine, and was going to have line techs examine further (I don't know if that has happend).  Of course the day he was here we were pretty stable and fast.  🙂  After that though, it's a bit random - if I'm getting high speed, I get drops.  If I reboot, I may get high speed (and continue drops), or back to 30Mbps but fairly stable.  And when very I'm lucky, I'll get both (right now I'm at 293Mbps down and no connection errors for 4 hours), but it'll last a day at most before starting to drop intermittently again.  A reboot (or 2 or 3) gets me back in business for about another day.

 

I've taken to monitoring the connection status from a Linux box that's directly connected to the gateway and also connected to my internal wireless (so I can get to it even if the gateway is down/rebooting).  "ping -i 10 -f -n -4 www.google.com" does a nice job - just leave it in a window, it'll ping Google every 10 seconds and print a dot, and then erase that dot as soon as the response comes in.  Ideally you get nothing but a blank screen - when the intermittent connection drops hit, it leaves a dot on the screen for every dropped ping.  No timestamping with this, but it does a nice job of showing when things have gone downhill, and I can correlate that it's not just google having an issue (when dots start appearing, all internet traffic is pretty much deceased).

 

The XB6 doesn't have nearly the detailed log folks are showing above (only seeing radio harvester thread start notices and my admin signons).  I can try posting downstream/upstream/CM error info if helpful although it doesn't grab as nicely as above.

 

HW details on the XB6:  under the hood it's a Technicolor XB6 version 2.2, BOOT Version:S1TC-3.49.18.14, Core Version:1.0, Model:CGM4140COM, Product Type:XB6, Download Version:Prod_18.1_d31 & Prod_18.1

 

Any hints, suggestions, or help would be very much appreciated!  

Responses

EG

Expert

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88.1K Messages

1 y ago

Quite welcome !

Contributor

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15 Messages

1 y ago

EG, thanks lots for the help you've already given me for helping route this, I really appreciate it.

XfinityAmir

Official Employee

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6.4K Messages

1 y ago

Hello bluesrhythm, I'd be happy to look into your signal levels to see what's causing your problem. To begin our journey please send me a private message with your full name and street address by clicking on my name (ComcastAmir) and then click "Send a message".

Contributor

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15 Messages

1 y ago

Thanks ComcastAmir, I sent you my details by private message (yesterday?) - any help would be much appreciated!

 

Still seeing a lot of dropping, and noticing that the modem keeps losing the lock on the OFDM downstream channel.  Sometimes it will re-establish on its own, sometimes a reboot required to reset everything.  I noticed that the power levels on all the downstream channels are noticably higher than they were on a prior post - not sure if that's just because of the splitter reconfiguration I did (replaced 3-way to modem/dvr/tv with 2-way to modem/another 2-way to dvr/tv) or if Comcast adjusted an amplifier somewhere.  The SNR still looks about the same.

Downstream Bonded Channels
ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectables
1LockedQAM25637675000000 Hz4.5 dBmV39.8 dB00
2LockedQAM2569507000000 Hz2.6 dBmV40.1 dB00
3LockedQAM25610513000000 Hz2.6 dBmV40.1 dB00
4LockedQAM25611519000000 Hz2.7 dBmV40.2 dB00
5LockedQAM25612525000000 Hz2.8 dBmV40.3 dB00
6LockedQAM25613531000000 Hz2.7 dBmV40.3 dB00
7LockedQAM25614537000000 Hz2.5 dBmV40.2 dB00
8LockedQAM25615543000000 Hz2.1 dBmV40.1 dB00
9LockedQAM25616549000000 Hz2 dBmV40.1 dB00
10LockedQAM25617555000000 Hz1.8 dBmV39.9 dB1424
11LockedQAM25618561000000 Hz1.9 dBmV39.9 dB2013
12LockedQAM25619567000000 Hz1.9 dBmV39.8 dB1718
13LockedQAM25620573000000 Hz2.4 dBmV40.1 dB3936
14LockedQAM25621579000000 Hz2.8 dBmV40.2 dB2746
15LockedQAM25622585000000 Hz2.9 dBmV40.2 dB3616
16LockedQAM25623591000000 Hz3 dBmV40.1 dB00
17LockedQAM25624597000000 Hz3.1 dBmV40.1 dB00
18LockedQAM25625603000000 Hz3.1 dBmV40 dB00
19LockedQAM25626609000000 Hz2.8 dBmV39.8 dB00
20LockedQAM25627615000000 Hz2.4 dBmV39.5 dB00
21LockedQAM25628621000000 Hz2.2 dBmV39.5 dB00
22LockedQAM25629627000000 Hz1.8 dBmV39.3 dB00
23LockedQAM25630633000000 Hz1.7 dBmV39.2 dB00
24LockedQAM25631639000000 Hz1.6 dBmV39.1 dB00
25LockedQAM25632645000000 Hz1.7 dBmV39.1 dB00
26LockedQAM25633651000000 Hz1.5 dBmV39 dB00
27LockedQAM25634657000000 Hz1.8 dBmV39.2 dB00
28LockedQAM25635663000000 Hz2.5 dBmV39.5 dB00
29LockedQAM25636669000000 Hz3.4 dBmV39.8 dB00
30LockedQAM25638681000000 Hz5.2 dBmV40.4 dB00
31LockedQAM25639687000000 Hz5.1 dBmV40.4 dB00
32LockedQAM25640693000000 Hz3.5 dBmV39.9 dB00
 
Upstream Bonded Channels
ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower
1LockedATDMA15120 Ksym/sec36500000 Hz44.5 dBmV
2LockedATDMA25120 Ksym/sec30100000 Hz45 dBmV
3LockedATDMA35120 Ksym/sec23700000 Hz45.5 dBmV
4LockedATDMA45120 Ksym/sec17300000 Hz45 dBmV
5Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
6Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
7Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
8Not LockedUnknown00 Ksym/sec0 Hz0.0 dBmV
 
Downstream OFDM Channels
ChannelLock
Status
Modulation /
Profile ID
Channel
ID
FrequencyPowerSNR /
MER
Active Subcarrier
Number Range
Unerrored
Codewords
Correctable
Codewords
Uncorrectable
Codewords
1Locked0159702000000 Hz0.6 dBmV40.5 dB1546 ~ 254939407719450
2Not Locked000 Hz0 dBmV0.0 dB0 ~ 4095000
 

Contributor

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15 Messages

1 y ago

Just circling back with everyone - it looks like local support got this fixed up even before ComcastAmir and I were able to start working on it together.  Last Friday I was pretty dead in the water from a connection standpoint - a ton of drops, very unreliable connection speeds.  About noon there was a tech working at the pole right outside the house - not a lot of improvement when he was done, but I noticed upstream power levels had climbed a touch and the downstream levels had dropped but also flattened.  However, there were other trucks working nearby in the neighborhood so I figured work was continuing.  Overnight we dropped completely for quite a while - then came back up, and by about 11am Saturday we were clocking in at about 400Mbit/s and, much more important of late, no noticeable connection drops at all.

 

Since then (it's now Tuesday morning) I've seen just a sprinkle of connection drops, and only on my ping monitors - I haven't actually noticed any outage.  Speed remains consistently high - from what I can tell I'm actually hitting performance limits on the test gear now, so I may be getting even higher speed at the modem itself.

 

So, tl;dr - problem was definitely outside the house and, it appears, probably beyond our pole as well, and Comcast got me back in action.  

 

Thanks to everyone who contributed on this thread - I learned a bunch, and I'm sure some of the work we did helped improve in-house performance too, so it was time well spent.

XfinityAmir

Official Employee

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6.4K Messages

1 y ago

Thanks for the update Chris, I am overjoyed that we were able to get this issue resolved for you. Feel free to reach back out to me here or create another post if you need anything else in the future. Have a good day and thank you for being a member of the Comcast family 🙂 

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