11-18-2008 01:50 AM - edited 03-04-2019 12:23 AM
We have a Cisco 837 router at site which appears to be randomly dropping and reconnecting at various times. From looking at the logs, the downtime is only around 15 - 20 seconds, but it is causing issues for the users. I have provided the ATM debug information in a text file attached to this post and would be greatful if someone could help me understand it.
Thanks,
11-18-2008 06:04 AM
Hello Stuart,
there are two event cycles that appear multiple times and appear multiple times in your log file.
Both event cycles lead to ATM/ADSL interface change state to down
first is:
Nov 17 18:47:33.081: DSL: Defect: LOS LOF LCDf LOM: retraining
Nov 17 18:47:33.081: DSL: Received response: 0x41
Nov 17 18:47:33.769: Resetting ATM0
Nov 17 18:47:35.517: %LINK-3-UPDOWN: Interface ATM0, changed state to down
this tells that an error code has been received on the line and the interface is resetted.
second event cycle :
Nov 18 05:56:46.922: DSL: Using subfunction 0x15
Nov 18 05:56:46.922: DSL: Using subfunction 0x15
Nov 18 05:56:46.922: LOCAL:Max noise margin for power cutoff 31
Nov 18 05:56:46.922: DSL: Sent command 0x3
Nov 18 05:56:47.514: %LINEPROTO-5-UPDOWN: Line protocol on Interface ATM0, changed state to down
In this case the signal to noise ratio here the noise margin has gone under a threshold and this makes the line to be resetted to negotiate again the various line parameters.
I would suggest to ask the provider to perform some test on the line, it looks like that there can be some trouble over it.
There have been also cases where a firmware upgrade solved the issue and this can be achieved also by an IOS upgrade.
However, the line appears with troubles.
Hope to help
Giuseppe
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