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Callmanager MWI Question !!!

When the wireless IP phone is powered OFF, the phone is unregistered with the Callmanager. A VM message is left for the subscriber. Unity traces show that the subscriber has a new voice message and the MWI activation request is sent to CCM and status of subscriber MWI on Unity is ON.

Now after Unity instructs Callmanager to dial MWI for the particular extension, (note that the extn or phone is unregistered), ......

1)Will Callmanager send a MWI ON message to the unregistered phone? Or, does the Callmanager wait until the phone gets registered again? Or, does it just discard the MWI message seeing that the phone is not registered?

2)Where is the MWI status of the IP phone stored, on the Callmanager or on the IP phone itself?

When the phone is powered ON later, there is no MWI light on the phone indicating a new voice message.

Please help on the two questions !!!



Community Member

Re: Callmanager MWI Question !!!


I've come across similar situation and I Re-Sycn WMI in Unity.

I'm enclosing the MWI URL. Go to Switch portion and at the bottom you'll see Re-sync.

Please let me know hot it goes.



NYC, Department of Correction


Re: Callmanager MWI Question !!!

Thanks Raj. If I Resynch, I get the correct status on phone. What I am interested in knowing is the answer to the two questions I asked earlier. I need to know how Callmanager reacts to MWI messages for a device that is unregistered.


Cisco Employee

Re: Callmanager MWI Question !!!

I'm a developer who works on the part of Unity that interfaces with CallManager (AvSkinny.TSP). I don't the exact internal workings of CallManager, but I'll explain Unity's role in this, and my best guess at what CallManager does.

When Unity sends an MWI request to CallManager, it does not get any response code from CallManager about whether the phone is registered or even if it's an extension in the CallManager's database. In other words, if we send an MWI request for extension 1000 and the CallManager doesn't even have an extension 1000 (or in your case, 1000 is unregistered), CallManager doesn't give us a different response than it does in the case where 1000 is a valid, registered IP phone. Unity has to rely on CallManager to do the right thing with the MWI request - in other words, to tell the IP phone to turn it's MWI on or off.

Now, as to your questions:

1) CallManager doesn't have any way of communicating with an unregistered phone, so it can't send an MWI request to it. As for what CallManager does with the MWI request, I'm not exactly sure. My understanding (and again, I work on Unity, not CallManager, so I could be wrong here) is that CallManager has an internal database that contains the MWI status for each extension, and it updates that database when Unity tells it to. I think the problem you're running into happens because when a phone registers with CallManager, CallManager does not send it an updated MWI status, so the phone assumes its MWI should be off.

2) Again, I'm not a developer for CallManager or the phones, but my understanding is that the IP phones are for the most part stateless, meaning they don't keep track of their MWI status and such between reboots/re-registers. They rely on CallManager to tell them their status. So, in the case of MWIs, if a phone is registered when Unity tells CallManager to change the MWI status, then the phone's MWI status is updated correctly, but if they are unregistered, they will not get the updated MWI status when they do finally re-register.

Again, as I've said a few times, I'm not a developer for CallManager, so this is only my best understanding of how things work, but it does seem consistent with the behavior you're seeing.


Re: Callmanager MWI Question !!!

Thanks for your response, it sure makes sense to me, and helps too.



Community Member

Re: Callmanager MWI Question !!!

tested on CCM 3.3.2 with 7960 phone. Unplugged a phone that had no messages. Called and left message. Plugged phone in, registered with CCM and MWI is on.

What version of CCM do you have and what is the wireless IP phone (7920?)

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