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Beginner

Cisco IP Phones goes into Preservation Mode.

Hello Experts,

 

 I am facing one issue. We have CUCM servers and IP Phones in same LAN but stills Cisco IP Phones gets unregistered for 30 to 45 seconds when phone in idle mode. And in ongoing calls, phone goes in preservation mode. This is happening with any random IP Phone.

CUCM Ver is 10.5.

 

Can someone help out here?

 

Thanks in advance.

1 ACCEPTED SOLUTION

Accepted Solutions
Cisco Employee

Re: Cisco IP Phones goes into Preservation Mode.

I would still ask you to check your network. Switches, routers, firewall if any on the path.
Check if their is a monitoring system on your network that does polling during the time when the phones un-register.

Nipun Singh Raghav
"We cannot solve our problems with the same thinking we used when we created them"
9 REPLIES
Cisco Employee

Re: Cisco IP Phones goes into Preservation Mode.

Check your switchports for any errors. If there is a pattern, look into the cabling.

Nipun Singh Raghav
"We cannot solve our problems with the same thinking we used when we created them"
Beginner

Re: Cisco IP Phones goes into Preservation Mode.

Thanks Nipun,

 

But I don't see any errors on switchports and also desktops are connected to PC ports of IP Phones are working fine.

Most of the time IP phones works but users are facing this problem 4 5 times in day.

Cisco Employee

Re: Cisco IP Phones goes into Preservation Mode.

Get a SDL trace for a couple of timestamps. The trace should be starting at a time when phones are registered and end when they re-register.

Nipun Singh Raghav
"We cannot solve our problems with the same thinking we used when we created them"
Beginner

Re: Cisco IP Phones goes into Preservation Mode.

Hi Nipun,

 

I have collected packet capture of Phone and I found some logs as follows.

 

<Enum name="ReasonForOutOfService">10</Enum>

&

<Enum name="ReasonForOutOfService">23</Enum>

 

code 10 ==The TCP connection to the Cisco Unified Communication Manager experienced a timeout error

Code 23 ==The device closed the TCP connection due to a restart command from the Cisco Unified CM

 

But can you tell me possibilities  of why CUCM experienced a timeout error?

 

Regards,

Mangesh

Cisco Employee

Re: Cisco IP Phones goes into Preservation Mode.

I would still ask you to check your network. Switches, routers, firewall if any on the path.
Check if their is a monitoring system on your network that does polling during the time when the phones un-register.

Nipun Singh Raghav
"We cannot solve our problems with the same thinking we used when we created them"
Beginner

Re: Cisco IP Phones goes into Preservation Mode.

Hello Guys,

 

 

  We found the root cause of this issue. We observed that CPU utilization of Access layer switches was more than 97% which was causing disconnection between CUCM and IP phone.

 

Regards,

Mangesh

Beginner

Re: Cisco IP Phones goes into Preservation Mode.

 
Beginner

Re: Cisco IP Phones goes into Preservation Mode.

Why can't you check cucm server clusters mgcp or cvp servers with rtmt logs, always saying that switches, routers , link, firewall, I'm asking one question , getting preservation mode related to call preserve or phone preserv

Re: Cisco IP Phones goes into Preservation Mode.

so what was the issue and what is the solution?  I have this issue as well.  We haven't had any issues with our system or any end points for over 4 years, but this year we are replacing switches and have two different admins managing the system with different sets of knowledge and different ways of doing the same thing.  Looking for what the solution was to make it stop.

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