20-5
Cisco ASA Series Firewall CLI Configuration Guide
Chapter20 Configuring Cisco Intercompany Media Engine Proxy
Information About Cisco Intercompany Media Engine Proxy
The TLS signaling connections from the Cisco UCM are terminated on the adaptive security appliance
and a TCP or TLS connection is initiated to the Cisco UCM. SRTP (media) sent from external IP phones
to the internal network IP phone via the adaptive security appliance is converted to RTP. The adaptive
security appliance inserts itself into the media path by modifying the SIP signaling messages that are
sent over the SIP trunk between Cisco UCMs. TLS (signaling) and SRTP are always terminated on the
adaptive security appliance.
If signaling problems occur, the call falls back to the PSTN; however, the Cisco UCM initiates the PSTN
fall back and the adaptive security appliance does not send REFER message.
Architecture and Deployment Scenarios for Cisco Intercompany Media Engine
This section includes the following topics:
•Architecture, page20-5
•Basic Deployment, page 20-6
•Off Path Deployment, page 20-7

Architecture

Within the enterprise, Cisco Intercompany Media Engine is deployed with the following components for
the following purposes:
•The adaptive security appliance—Enabled with the Cisco Intercompany Media Engine Proxy,
provides perimeter security functions and inspects SIP signaling between SIP trunks.
•Cisco Intercompany Media Engine (UC-IME) server— Located in the DMZ, provides an automated
provisioning service by learning new VoIP routes to particular phone numbers, and recording those
routes in Cisco UCM. The Cisco Intercompany Media Engine server does not perform call control.
•Cisco Unified Communications Manager (Cisco UCM)—Responsible for call control and
processing. Cisco UCM connects to the Cisco Intercompany Media Engine server by using the
Access Protocol to publish and exchange updates. The architecture can consist of a single Cisco
UCM or a Cisco UCM cluster within the enterprise.
•Cisco Intercompany Media Engine (UC-IME) Bootstrap server—Provides a certificate required
admission onto the public peer-to-peer network for Cisco Intercompany Media Engine.
Figure 20-2 illustrates the components of the Cisco Intercompany Media Engine in a basic deployment.