DSL state machine process High CPU

[Joris Deprouw]

Hello,

We have a Cisco 886 configured with two WAN's (ATM0 connected to a DSL line and Fa3 connected to a CMTS modem).

We're running  DMVPN over the Cable network and GetVPN over the DSL line. When the DSL line is down we see a lot of CPU peaks up to 90%.

The CPU peaks are caused by the process "DSL state machine". As soon as the DSL line has sync and the ATM0 interface goes UP the CPU peaks disappear. What we'd like to know is if this constant extra CPU load will have an impact on other resources like normal routing & switching or more specific IPSEC handling. Is it for example possible that establishing an IPSEC tunnel will fail because of the CPU peaks?

Thanks,

Best Regards,

Joris

[paolo bevilacqua]

Which exact IOS are you running ?

[Joris Deprouw]

Hi,

I'm running version 15.1(2)T0a.

[paolo bevilacqua]

Update to 15.0(1)M4 or 15.1(2)T2a.

If still troubles, contact the TAC.

[Joris Deprouw]

Thanks Paolo,

I'll try that. Is there a know bug in my current IOS?

Best Regards,

Joris

[paolo bevilacqua]

IOS has always many bugs. Update and report here.

[Joris Deprouw]

Paolo,

Can the high CPU affect other processes like IPSEC?

I suppose it does.

At this time we didn't experience any problems like that.

Thanks,

Joris

[Richard Burts]

Joris

While CPU spikes will have some impact on other processes that use the router CPU I doubt that the CPU spikes up to 90% that you describe would have a serious impact on processes like IPSEC. And I certainly do not think that it would be serious enough for an IPSEC connection to fail, or fail to establish.

HTH

Rick

[Joris Deprouw]

Hi,

Too bad. The upgrade didn't work.

We have upgraded to version 151-3.T . But we can see the same CPU elevation when the ATM interface goes down. However, no other processes are impacted at this time.

Other suggestions?

Thanks,

Joris

[Leo Laohoo]

When the DSL line is down we see a lot of CPU peaks up to 90%.

And how often does the DSL line go down?

I'd ignore this because if your DSL line is OK. 

[Joris Deprouw]

Hi,

The DSL line is not often down. So the CPU peak is not a common situation. But we are worried that when the DSL goes down, the high CPU peak will cause other processes to block.

That's why we would like to have this issue solved.

Thanks,

Best Regards,

joris

[paolo bevilacqua]

Please try one of the two images I've recommnded above.