All versions of the ETM® Unified Trunk Application (UTA).
A limitation exists in the Cisco Unified Communication IOS Services API (CUCISAPI)
that supports UTA that impacts how dial peers can be configured when using the API.
When a call comes in, the CUCISAPI runs a function called address_analyze that
sends the called and calling numbers to UTA for Policy processing. The call is held
in the Integrated Services Router (ISR) or Aggregation Services Router (ASR) awaiting
UTA Policy processing to determine whether the call is to be allowed, redirected, or
terminated. If Policy dictates that call is to be allowed or redirected, it is routed
to its destination. However, the address_analyze function also strips the URI,
so the call is routed to the next call leg based only on the phone number. Therefore,
dial peers must be configured to use the phone number rather than the voice class
URIi as the criteria.
In addition, certain versions of Cisco iOS for voice-enabled ISRs/ASRs support using
server-groups. However, server-groups are not compatible with the CUCISAPI, because
this causes the API (and therefore UTA) to lose track of the call, since the session
target is effectively hidden from the API in this configuration.
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