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Call forwarding not working ( Vodafone Germany)

Level 1
Level 1

We have a Cisco Model ISR4321/K9 router with Cisco IOS XE Software Version 16.09.04
The problem occurs when we make a call forward to an external number.
The call made by User A to the destination User B (user B has activated a call forwarding to another external number User C)
User C answers the call, user C does not hear anything, User A does not hear anything either, but after 18 seconds the call closes automatically by itself.

User A -->+49xxxxxxx90 ...incoming call 

User B--> +49xxxxxxx55 --> call forward to  User C   

User C--> +49xxxxxxx30 .....Extern number ( external forwarding is configured on the router) 








voice service voip
no notify redirect ip2ip
allow-connections sip to sip
no supplementary-service sip moved-temporarily
no supplementary-service sip refer
fax protocol t38 version 0 ls-redundancy 0 hs-redundancy 0 fallback pass-through g711alaw h323


voice register global
mode cme
source-address 172.20.XXX.XX port 5060
max-dn 10
voice register dn 2
number +49xxxxxx55
call-forward b2bua unregistered +49xxxxxx30


Can someone help me to solve this problem

BR ,



20 Replies 20

Hi Roger ,

I have configured the external forwarding in the Cisco Router.

Example :

voice register global
mode cme
source-address 172.20.XXX.XX port 5060
max-dn 10
voice register dn 2
number +49xxxxxxxx
call-forward b2bua unregistered +49xxxxxxxx


It is very true that I can do the forwarding from the PBX, but in my case I do it from the GW



Wow, that is one ugly way of managing call forwards as that is something that only a gateway admin can influence. I mean there will never be any calls that reach the original intended recipient, aka called number B and for any change needed a gateway admin would need to be consulted. Apart from that you use a licensed option, ie CME, for something that is easily and better managed in the PBX.

If I may come with a suggestion, if all that you want to do is to hair-pin the call in the gateway you can do that with voice translation rules instead. To do so you would match the called number B ingress from the service provider and translate it to number C in a way so that it matches the destination number set on the outbound dial peers towards your SP.

Response Signature

Hello Roger,

If I had thought of doing it that way.
but as I mentioned before, it is only for a "Virtual" number, which does not exist in the PBX.

Thank you very much for your valuable collaboration and recommendations.

Have a nice day

Best regards,


I agree with Roger in that this is not a clean way to mange call forwards at all. 

You are using a licensed feature (CME) just for call forwarding but you can use translation rules instead which requires no licenses.  

Also, when you configure call forwarding at the gateway level, internal to internal calls won't be forwarded. 

Hello TechLvr ,

This configuration was for a special requirement. (temporary for a single number)
Since physically in the PBX  there is no device and there is no internal number either

Thank you very much for your comments



Level 1
Level 1

Hi All , 

Thank you very much for your help, I solved the problem myself.


*Vodafone Provider*

Router Cisco ---> 

Router> enable

Router# configure terminal

Router(config)# voice service voip

Router(config-voi-serv)#notify redirect ip2ip

Router(config-voi-serv)#supplementary-service sip refer

Router(config-voi-serv)# supplementary-service sip moved-temporarily

Router(config-voi-serv)# exit