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New Member

Unity looping condition

I read the forum regards the Unity looping issue but not clear yet the definition and solution. please guide me to make clear.

I'm hear looping if I configure as follows,

-CCM, #1000 fwd all to VM

-Unity, #1000, Call transfer=1000, Greeting(source=blank, after greeting=transfer to Subscriber 1000).

Is this the definition so called looping then what's solution?

Thanks in advance,

13 REPLIES
Cisco Employee

Re: Unity looping condition

Yes - that is a definition of looping. The solution is to not do that.

Having a call handler or a subscriber that has a blank greeting and an after greeting action set to go to it's own transfer rule is not a good idea. This should only be used in some very special circumstances where the phone being transfered to is not being forwarded back to Unity.

Are you having a problem with this or are you just a naturally curious person who wants to know what this is?

New Member

Re: Unity looping condition

Thanks Jeff,

Yes, not do that is the solution but practically may happen by mistake and I want to find out a solution though.

I cannot stop the looping even tried as per the recommentation the URL for Unity connection.

http://www.cisco.com/en/US/products/ps6509/products_administration_guide_chapter09186a008055703f.html#wp1043226

Is it impossible to stop the looping for my scenario or any solution to prevent?

Thanks,

Re: Unity looping condition

Hi -

Hope you don't mind me asking, but what are you trying to accomplish? It looks like you have a CTI route point in CCM, with a directory number of 1000 that forward all calls to Unity. Unity has a call handler with a directory number of 1000 which attempts to transfer to a subscriber's phone with extension 1000. You should not have both a CTI route point and a phone defined with the same extension. Outside callers are going to reach the CTI route point, not the subscriber. But perhaps if you tell us what you want to accomplish with your call flow, we can help you better :-)

Ginger

Cisco Employee

Re: Unity looping condition

yeah, knowing what you're trying to do would be good here.

Unity can detect looping if you're staying in the Unity system - but since you're forcing us to transfer out and then the call comes back in as new and then you're forcing us to then transfer again, there's no way we can detect and stop this.

This isn't likely to happen by accident - gotta say in the 8+ years or so we've been shipping product like this (same problem can be inflicted on just about any voice mail system or IVR with an auto attendant if you try hard enough) I've never seen a case come to us where someone "slipped" and set this up by accident.

New Member

Re: Unity looping condition

Hi Jeff,

you say Unity can detect Routing loops within the system. Is this default or does it need to be configured/enabled? If so, where can I do this?

Thanks and Kind Regards,

Markus

Cisco Employee

Re: Unity looping condition

If you loop a call handler back to itself, for instance (which can happen by accident due to a configuration error), Unity will detect the same object being loaded a number of times and will kill the call. I believe the number has changed but it should be around 20 regardless of version. This isn't something you can turn off.

You can fool it if you try hard enough - if you loop a "chain" of handlers in a circle then Unity does not detect that the same, say, 7 call handlers are being loaded one after another in a circle - loop detection isn't that sophisticated.

Normally this only comes up if for some reason a disconnect got missed which doesn't happen a whole heck of a lot with phone systems these days - used to be a bigger problem in old analog PBXes.

New Member

Re: Unity looping condition

Hi Jeff,

thank you for your quick and good response. The thing is the following: I would not have worried about such a loop problem by myself, but I was in a CCIE Voice Exam 3 weeks ago and one point the lab wanted me to configure was exactly that.

The task said (short) "Configure Unity to detect and break loops"

So if there was nothing to configure, it would not be worth 2 points for them I guess :-)

Do you have an idea what they wanted me to do?

In the lab it is Unity 4.0(5)

Thanks a lot for your help.

Kind Regards from Berlin,

Markus

New Member

Re: Unity looping condition

Markus,

I am trying to figure this out also, to no success it seems.

Frank

Cisco Employee

Re: Unity looping condition

To configure a loop, simply configue a call handler to play a greeting, and then set that call handlers action after greeting to go back to the same call handler greeting.

It's that simple... Now if you call in and hit that call handler, after it plays the greeting, it will loop back and play the greeting over again and the process will repeat about 20 times, at which point Unity will say this system is temporarily unavailable, drop the call and logged an event in the application event log.

New Member

Re: Unity looping condition

We are looking for how to configure "Unity Loop Detection". This is possible with Unity Connection under the Integration section.

A document for Unity & CME states if you connect it with CME "Unity Loop Detection" will not function. However it doesn't say how it DOES function with CM, or if it needs to be turned on.

Any insight?

Thanks,

Frank

New Member

Re: Unity looping condition

Hi Frank,

I had the same problem as you. In my CCIE exam they asked me to configure Unity (!) Loop detection. I found some posts on some CCIE forums which said the following.

When you configure the Unity Ports, configure them with the DN of the Callmanager Unity Ports. Then in Call Routing configure manually that whenever one of this "callers" calls Unity to send this call to a CallHandler to terminate the call.

I did this and it worked - I could break the loop, that I configured although in my CCIE exam I earned exactly 0 points for that :-(

So actually I?m totaly confused about this...

Don?t know if this helps you.

Markus

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