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Can CRC ERRORS cause corruption to data???

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Can CRC ERRORS cause corruption to data???

I got Plusnet in for the static ip an cheep 1 meg line to comunicate with my office via vpn.
This will be live in about a week or so. But my line is getting CRC ERRORS ( 8000 in a 2 day period for example)
Can these CRC ERRORS corrupt the data ?
10 REPLIES
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Can CRC ERRORS cause corruption to data???

CRC errors mean your line is receiving corrupt data.

A CRC check is designed to check if the incoming data is valid. By appending a small checksum onto the data, the end machine can see if it is valid.

If not, you have a CRC error.
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Can CRC ERRORS cause corruption to data???

So I guess that means YES?

As I was never getting errors when conected to bt broadband. Are you saying the data is now getting corrupted due to my PlusNet connection.

If this is the case then unfortunately Plusnet will have to go. I will not take a chance with the data in my office.
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Can CRC ERRORS cause corruption to data???

I would advise you to wait a week.

There is a known problem, though tracking of it can't realy take place until tomorrow.

Where are you seeing the CRC errors? On the modem or in TCP data?

If it is the modem, this strongly sounds like a issues with the BT network.

Allthough it is the same BT network you where connected to with BT Broadband, there are a lot of different peice of equipment involved between the two ISPs, most of which is under BT's control, and not PlusNets
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Can CRC ERRORS cause corruption to data???

The Errors are shown in my routers ADSL Status (6329 for a 21 hour period up to now)

I have taken this to task with teck support over the phone. Who say "the prob is with BT, that there might have been a mistake made at the change over" Also " We can not ask bt to look at it as I am not getting disconected " ( I am now actualy starting to get discons also ).

So it looks as if I have some phone calls to make between BT and Plusnet as this is no good at all....
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Can CRC ERRORS cause corruption to data???

Line sync problems are definatly BT.

Disconnections, such that no sync is lost can be either PlusNet or BT.

PlusNet may be thinking of asking BT to rollback the 9th pipe install tomorrow morning, to see if it has introduced any problems. See if they are any better in the morning.

PlusNet also have plans for more work during the week to clear up routing problems (shouldn't be causing CRC errors) and other possible issues.

CRC problems on the router are generated either on the gateway device at PlusNet, or within the BT network. Other ISPs are seeing very simalar issues, so it is being looked at as a generic fault in the ADSL network of BT.

Getting BT to acknowledge faults can be tricky though.
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Can CRC ERRORS cause corruption to data???

Given that we can't expect 100% data integrity what should be considered reasonable in terms of dropped packets 'cause of crc failures?
Community Veteran
Posts: 6,983
Thanks: 8
Registered: 10-04-2007

Re: Can CRC ERRORS cause corruption to data???

Quote
Can these CRC ERRORS corrupt the data ?


We seem to wandering away from the original question now in this thread.

In theory the answer is no they will not cause errors as the whole idea of the CRC is to spot the error in the data and have the errored packet resent.
Having said that if a lot of errors are showing up then it is an indication that there is something wrong in the system.
In my days many years ago setting up data circuits the testing involved making a check on the number of errors in the form of "Number of errors / Thousand data bits sent" I cant remember the exact guidline figures now as it was so long ago, but the figure of 1 error per 10,000 bits seems to ring a bell as being within limits.
Ianwild
Grafter
Posts: 3,835
Registered: 05-04-2007

Can CRC ERRORS cause corruption to data???

Hiya,

Yep, a small number of CRC errors (Maybe 2 or 3 in a 24 hour period) might be considered normal. That amount of errors is not normal, but the CRC checking occurs within your private BT circuit and if there is a problem here it is occuring well before it hits our network.

We do need to log this as a fault with BT for you and if you could raise a ticket using link:Contact Us and email me the ticket number (iwild@plus.net) I will ensure this gets dealt with promptly.

Regards,

Ian
Simon_M
Grafter
Posts: 684
Registered: 05-04-2007

Can CRC ERRORS cause corruption to data???

Note to Plusnet Support staff.

Intertex have Firmware v 2.06 in beta test for their IX-66 router. This firmware is reporting a high number of CRC errors. This is thought to be a bug in the firmware rather than an indication of a sudden rise in actual errors.

As far as I know, all users of this version of the firmware are aware of the problem, so it is unlikely to be reported to you, but if you get a report of CRC errors with no other apparent explanation, it might be worth "eliminating from your enquiries".

Simon
Ianwild
Grafter
Posts: 3,835
Registered: 05-04-2007

Can CRC ERRORS cause corruption to data???

Thanks for that Simon....