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CRC Errors on Downstream

zombies
Grafter
Posts: 29
Registered: 07-08-2008

CRC Errors on Downstream

We (like many others) recently had issues with severe lightning - it managed to kill the modem on my Netgear DGND3300v2 router, so much so that it never tries to sync and never tries to do anything, but the rest of the router seems to work OK.
I swapped that router out with the old and trusty Netgear DG834GT and we had internet service once again.
I ordered a replacement router - the Asus DSL-N66U, it's configured and all working fine.
After running a speed-test or 2 I notice my throughput has gone from an average of 4.3Mbps to 5.3Mbps - so I was a happy bunny.
I accidentally rebooted the router (turning off the wrong plug in a bank) - upon reconnection and looking at the DSL Log section of my router, I noticed some CRC Up and CRC Down errors.
I'll admit I hadn't noticed these previously, so simply watched them for a while - whilst I surfed.
I noticed that my throughput had dropped down to around 3.2Mbps and everything was taking an absolute age to load up.
I powered off the router, disconnected the microfilter, reconnected and powered it back up.
As before the previous reboot - fast speeds again and things seemed to be working well.
So I'm not sure where the issue actually is, prior to the lightning our internet was at least usable, it had it's moments where it would stall a little but nothing like how it was using the 31.185.197.146 IP address (and probably different gateway too?).
Speedtest.Net tests:
#1 - 15/1/2014 19:10 GMT 87.112.120.96 5.30 Mb/s (Didn't spot any CRC errors)
#2 - 15/1/2014 20:59 GMT 31.185.197.146 3.66 Mb/s 0.36 Mb/s (Spotted many CRC errors in the 10K range on CRC Down)
#3 - 15/1/2014 21:24 GMT 87.113.239.209 5.01 Mb/s 0.36 Mb/s (No CRC errors)
Here is what the router is currently showing me in the DSL Log:
DSL Driver Version FwVer:5.4.11.21_A_TC3095 HwVer:T14.F7_0.0  
DSL Link Status up  
DSL Uptime  0days 0hours 1minutes 33seconds  
DSL Modulation ITU G.992.1(G.DMT)  
Annex Mode ANNEX_A  
SNR Down 2.5 dB  
SNR Up 17.0 dB  
Line Attenuation Down 40.0 dB  
Line Attenuation Up 19.0 dB  
Data Rate Down 6656 kbps  
Data Rate Up 448 kbps  
MAX Rate Down 6304 kbps  
MAX Rate Up 960 kbps  
POWER Down 20.0 dbm  
POWER Up 12.5 dbm  
CRC Down 0  
CRC Up 0  
Not sure if the problem is in my line, my exchange, plusnet or my new router.
Does anyone have any ideas here? I'm reluctant to reboot the router in-case it goes 'bad' again.
Could someone from Plusnet take a look at my connection statistics over the last 2 hours to see if they are seeing CRCs as well?
Update: I now recall that after around 10K CRC down errors, it dropped my connection and I couldn't connect to any websites at all, had to reboot the router (as the router seems to have no 'disconnect' and 'connect' buttons similar to the Netgear routers I've owned)
2 REPLIES
Plusnet Alumni (retired) orbrey
Plusnet Alumni (retired)
Posts: 10,540
Registered: 18-07-2007

Re: CRC Errors on Downstream

Hi there,
Going by what you said, and on checking your connection logs, you have had a very intermittent connection indeed:
<img src="http://community.plus.net/visualradius/generated/image13898782431667.png"/>

I strongly suspect damage following the storm, to be honest. There's no way a new IP or gateway will make your connection drop, that's entirely between the exchange where the signal is generated and your premises and the wiring between.
I can see you've started raising a fault, please pop back to http://faults.plus.net and make sure you've answered all the questions or that'll get closed after 48 hours. If you follow it through as a dropping connection, once the questions are all answered it'll be passed through to our faults team who'll get things sorted out for you.
zombies
Grafter
Posts: 29
Registered: 07-08-2008

Re: CRC Errors on Downstream

Matt,
Thank you for your prompt reply - I have finished filling out the Broadband fault ticket and have pasted in the original content as well just in-case that gets deleted.
If you need me to do anything more, please let me know.  Smiley