When calling from a local IP phone to the Cisco Unity Express (CUE) voicemail pilot number, the calls reach voicemail. When calling from the same IP phone through Call Forward No Answer (CFNA), the call to voicemail fails.
Calls forwarded from Cisco CallManager Express (CME) to CUE do so by virtue of the the telephony-service dialplan-pattern command configured on the CME. The general rule for this command is to expand addresses to E.164 addressing if that call goes outside of the router. This includes forwarding to CUE and is the cause of the problem.
This issue is documented in Cisco bug ID CSCee57422.
The Cisco IOS dialplan-pattern command is intended to make all Voice over IP (VoIP) calls use E.164 numbers.
When a CME is configured with a dialplan-pattern command that encompasses the CUE pilot access number, the CUE must therefore be configured to accept incoming calls that use an E.164 number. This is a similar situation to a direct dial into CUE (for example to retrieve voice messages) using an external phone. For example, voice mail 9017 becomes 01159829017. Adjustments need to be made on the CUE accordingly.
This is a workaround for this problem:
Downgrade to Cisco IOS Software release 12.3(7)T1. This interoperability problem has been reported in 12.3(8)T images only.
Do not use the dialplan-pattern telephony-service command.
Create a translation-rule on the CME for the dial-peer pointing to the CUE. This translation rule is used to convert the E.164 number back to extension number format so it is acceptable to CUE.
This is a configuration example:
voice translation-rule 1
rule 1 /0115982\(....\)/ /\1/
voice translation-profile cue
translate called 1
dial-peer voice 100 voip
description Voicemail number
translation-profile outgoing cue
session protocol sipv2
session target ipv4:172.16.32.61
In this way, any number sent to the voice mail is sent as a 4-digit number, and you do not need to modify anything on the CUE.
Multiple triggers may be configured on CUE through the Command Line Interface (CLI).
This is an example of two triggers for voicemail applications, one with trigger 3380 and the other with trigger 4085553380. Repeat this for all the applications (VM, AA, GMS) for which you need E.164 support: