Forward No Answer error

Unanswered Question
Dec 7th, 2007

CM 4.13

I Have have two CMs connected over an ICT.

If I dial a phone from cluster A to a phone on cluster B and the phone on Cluster B has a Forward No Answer setting to a phone on cluster A I get the message

"your call cannot be completed as dialled" I can only get this to work if I set a calling search space on the forward setting of the line.

call forward all works ok. Is this a bug?


I have this problem too.
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allan.thomas Fri, 12/07/2007 - 04:49

Whether you a calling from one cluster to another is not the problem you always have to define a Forward CSS when forwarding to a given destination. Otherwise how else will it match the pattern.

The IP phone that requests the CFA, CFNA, CFB settings must use a destination or dialed number that is contained in the Calling Search Space (CSS) or a partition that this phone has rights to call.

As you have discovered in your case the phone on cluster B is unable to forward to the destination phone on Cluster A simply because there is no CSS defined.

The same is applicable if the phone is not allowed to place calls PSTN, then any attempts to set the phone to forward calls to an outside number will fail unless the css permit external calling.

It is possible to set the line to a different CSS than the one the phone uses in order to further restrict or allow call forwarding destinations.

Hope this helps.



jamjam200 Fri, 12/07/2007 - 07:19

I have set a CSS on the phone its self but not on the line or under the forward setting.

I have CFA, CFNA, CFB set up in many other places and have not had to specify the CSS on the line or the forward setting as long as it has been set on the phone it works


allan.thomas Fri, 12/07/2007 - 18:31

Essentially we need to verify a few aspects, and I suspect that cluster B is this instance is deployed on either 5.x or 6.x?

If this is the case then this explains alot, to put it quite simply the Call Forward CSS behaviour has changed since the release of CCM 5.x.

When you have an opportunity take a look at the following guide which explain this in details, refer to section Directory Number Features. Below is the extract from this document:-

Cisco CallManager release 5.0 supports a secondary Calling Search Space (CSS) for Call Forward All (CFA) field. The secondary CSS for CFA combines with the existing CSS for CFA to allow the support of the alternate CSS system configuration. When CFA is activated, only the primary and secondary CSS for CFA get used to validate the CFA destination and redirect the call to the CFA destination. If these fields are empty, the null CSS gets used. The combination of the line CSS and device CSS no longer gets used when the CSS for CFA is None. Only the CSS fields that are configured in the primary CSS for CFA and secondary CSS for CFA fields get used. If CFA is activated from the phone, the CFA destination gets validated by using the CSS for CFA and the secondary CSS for CFA and the CFA destination gets written to the database. In previous releases, if the CSS for CFA is empty, the CFA destination got validated against the combination of the line CSS and device CSS of the phone. In this release, when the CFA is activated, the CFA destination always gets validated against the CSS for CFA and the secondary CSS for CFA.

Hope this helps



jamjam200 Mon, 12/10/2007 - 07:51

yep I was am aware of the new CSS design in 6 but this is version 4.13 sr5 (unless its changed in the SR)

why do cisco have to over complicate CSS with secondary??

allan.thomas Mon, 12/10/2007 - 11:02

Are both Cluster A and B running version CCM 4.x ? If this is the case then I would expect the CFA to use the Line/Device CSS if no CSS was specified.

With regards to the Secondary CSS, this provides the opportunity to configure a CSS which provides PSTN breakout. This can be a problem when using the Device and Line CSS approach. The device CSS which provide the external breakout, however CFA no longer uses the Line/Device CSS, hence the secondary CSS.



Mike Lydick Wed, 01/02/2008 - 15:54

Not directly answering your question but, I think you would want to take advantage of this as a security feature. Leaving the CFNA to the default Class of restriction (under the premise of this would inherit the same COR as the device), would allow for user Toll fraud. Just because I can call Granny in England directly does not mean by default I should be able to to have my co-worker forward his phone or mine to her and I call in after hrs.


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