ASR9001 conslole messages

[nenadl]

Hi all,

does enyone know meaning of this messages on ASR9001:

devc-conaux[56]: %MGBL-ST16550-3-ISR_MSR_ERR : Too many console line state change interrupts

Regards,

Nenad

[Nikhil Kapoor]

Hello Nenad, 

Based on the error logs. I am suspecting a bad console cable connected to 9k?

1. Please check if console cable is connected to 9k, If yes then please remove it and check if you still see the error logs. 

2. Also please check these error logs are causing any CPU hog?

I am assuming that dis-connecting the console cable would resolve the issue. 

HTH,

Nikhil 

[xthuijs]

this message is seen when the UART (the serial controller chip) is experiencing too many receive interrupts.

ASYNC communication is tricky because every char received will result in a receive interrupt that a driver will need to take of that receive queue for handling.

The UART may generate too many of those interrupts when the line is noisy, or when there are voltage fluctuations on the other side resulting in 1/0 transitions generating a perceived (but not real) START sequence for receiving new bits.

Another reason could be that when you have say a 2500 series router or any cisco ios based console server with exec enabled, this means that both ends are speaking to each other generating back and forth character sending resulting in an excess trigger of sesions on both end.

So check console cable, line noise, no-exec on the console server line side as a start.

regards

xander