I dont know your particular environment but typically a phone will have at least 2 connections as such:
1 TCP connection to a primary server (this is a fully established session) for call control
2 TCP connection to a second server (this is a fully established session) for call control
If you are lucky enough to have tertiary failover, the phone can connect to a 3rd CUCM but the session is not active and has to be fully established for failover to occur.
Your phone can also failover to an SRST router. This is similar to how tertiary failover works in most scenarios.
For you, when you see the UCM Down/Features Disabled this means the phone has lost connection to it's primary server. If this is happening frequently and your phones drop and come right back up, you should look at RTMT to see if your phones are dropping from one server and re-registering to a secondary resource (and do they stay registered or do they eventually failback to the primary). If so, you may want to check that you don't have a routing issue (i.e., flap) occurring on the network that is causing this issue. You could also do a bug scrub to make sure you aren't running into a firmware issue on a particular version of phone. However, I'd first take a look at how you have your CM groups and failover configured and look at connectivity between all voice servers and then all voice subnets (i.e., phones) to those servers. If you find that you can isolate the issue to a particular server, you may have a bad NIC or even just CPU spike. In that case, you could register phones to another server and see if the issue arises again.
Lastly, if this is on a number of phones - what I've said above would still go. If it is only one phone, I'd go simple first and check the cabling from the phone to the switch and/or the switchport on the switch itself.
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I also face the same problem.
My question is why the phone will drop the call and do a quick reboot. My understanding is when users see this error "CM down" on their phones when they are on the call, it should means call preservation is in progress while the phone actually lose the connection to the primary server. The call should not be dropped.
Hi Daniel / Esther,
Do the calls drop even when the call is within the system i.e. IP Phone to IP Phone or does this happen when the IP Phone is on a call with a PSTN party? If it happens when call is between IP Phone and PSTN, then that would ideally mean that the call preservation isnt correctly set up / enabled on the gateway.
It depends on what protocol you are using and also if you've configured things correctly for call preservation as well. There is also typically a timer for how long calls can remain in this state without being dropped. If the calls are dropping immediately then that's one thing. There are a number of things that could be at play there in additiona to the protocol and configuration as mentioned above. What are you experiencing and what are you using?
Hoping you are still active as this is an old thread. We are getting reports from a small number of users in one area which would indicate to me that it is more local to the affected individual than the Call Manager Cluster (CUCM 11.0 running on BE7KM platform supporting circa 3500 IP phones). We have huge problems with DAI, and port security which is another matter.
Really useful pointers for starters here but can I just clarify my understanding as correct:-
We are running SCCP on Cisco 7941/61s. Once a call is established between two telephone end points (IP phone to IP phone), the two end points maintain the network connectivity and the Call Manager subscriber is only involved in the initial setting and and then tearing down of the session. So even if a subscriber did fail causing the phones to register with their configured secondary or tertiary, the call itself shouldn't drop.
How can Cisco releases the CCNA Discovery and Exploration documentation with full of corrections in it. If you need proof you check my blog www.CiscoMistakes.blogspot.com. Take some necessary action. I am able to find 1 correction in 15-20 pages. Some of those are published in my blog. If you are not concerned with the documentation please report this to the concerned team or person.
This is Satya Rao (Mr. Perfectionist), a 28 year old South Indian guy, I have been taking CCNA training from the April 19th 2010, in one of the Cisco Networking Academy named IGIAT (Indo-German Institute of Advanced Technology) in Visakhapatnam, South India.
We know how important a proper documentation for any software or hardware. It should be given one of the major importance, without proper documentation the software or hardware is useless.
While I am reading your CCNA Discovery and Exploration materials I have found some corrections in the documentation. More than 300 corrections in the module 1 and 2 of CCNA Discovery and Exploration.
My correction checking includes spelling mistakes, punctuations errors, formatting errors, technical mistakes, diagrammatic error, etc.
I don’t want anyone to point out my favorite company’s documentation. Yes ordinary people may not find all of them but they will some of them.
Microsoft Windows is a 100% correction less documentation. I have studied lots of their documentation and unable to find not even a single correction, why not Cisco develops that kind of correction free, documentation to the world. Yes, it’s possible with me, the Mr. Perfectionist.
Please give me a chance to make it 100% correction less, yes the documentation is 99.999% good. But not 100%. Why should we take chance when Mr. Perfectionist is available?
Of course small punctuation corrections are not so big in terms of technical issues, but the high quality documentation must need everything to be high.
We all know that how many times it was checked before finalizing the documentation but still I found these many corrections.
If you want to test my talent or capacity give me your latest finalized version of any technical documentation and let me found the corrections in that documentation. You came to know how fast I will give you the 100% correction less out put.
Just imagine I have found these many corrections after you people done all kinds of proofreading before releasing to the world, how much useful I will be if I am in your documentation department.
I think you know, how hard it is find mistakes from a very great companies documentation like Cisco, (if not hard you would have released it 100% correction free to the world) not 5 or 10, I have found hundreds (still finding). If you really understand my talent you must give me a quality analyst job in documentation.
I know there are no vacancies but a person like me you should place me, to get better output, as the quality analysts there, unable to give the 100% quality.
I am ready to sign any kind of bond you wish.
You can fire me out at any time if you not satisfied with my work.
One of my weak point is I can’t tolerate if something is wrong or someone doing wrong. With this weak point I can easily find out mistakes in any documentation with ease at the maximum speed possible, which a computer can’t do.
Please someone recognize my work and effort and help me by providing a job with minimum possible pay. Willing to work 12 hrs a day at any time of the day.
I was worked as a proof reader in a medical transcription company for John F Kennedy hospital of California for one year.
I can give you results more than you expect from me.
Most importantly I need a job in my favorite company, Cisco. Willing to work from home too.
I think its not a big problem for a big company to give a job to a boy whose father died at his age 5.
Please give me one opportunity to prove myself.
If you came to know about this blog through an email, please forward the mail to the concerned person in the concerned department would be appreciated. (If not, humans help the humans who, will help the human kind.)
Thank you very much.
I have created one blog with some of those correction please check it.
I have not created this blog to generate some revenue, some popularity, or to point out the Cisco's mistakes to downgrade its standards. I just want to be one in the Cisco organization technical documentation team, for correction free documentation.
While that's all fine and dandy, this has nothing to do with the NetPro forums or the specific thread that you just overran with your manifesto. Please do not post this sort of rant in the technical threads.