Symptom
One-way audio, lack of audio, and/or call setup issues for voice traffic being handled by the voice card installed on the router.
Conditions
The combined use of CUBE (or a voice card/module -- FXO or FXS) and a zone-based firewall (ZBF/ZBFW) on the same router on the following router platforms:
* 4000 Series Integrated Services Router (ISR4K)
* 1000 Series Aggregation Services Router (ASR1K)
* Cloud Services Router 1000V Series (CSR1000V)
The use of IOS-XE software on the router.
Workaround
Place the service engine interface(s) applicable to the voice cards (which will be the "Service-Engine" interfaces with an "Up" state) in a zone that is used by the zone-based firewall and is on the normal path of the voice traffic. Contact Cisco TAC for more details about how to implement this workaround option.
Use a two-box solution, where the firewall functionality is on a separate appliance (dedicated firewall or router) from the router featuring the voice cards.
Further Problem Description
The combined use of voice cards and a zone-based firewall is supported on ISR G2 routers.
Also see defect CSCve23483, which contains the resolution of the issue behind why the voice card traffic does not properly work with ZBF without the stated workarounds. Any software version of IOS-XE that resolves CSCve23483 also resolves this defect (and allows for ZBF to be used with voice card traffic without any workarounds).
