As part of the introduction of Microsoft Live Communication Server (LCS) 2005, Microsoft offered a new PC-based software client called Microsoft Office Communicator (MOC). MOC supports instant messaging (IM) and can interwork with private branch exchanges (PBXs) and IP-based unified communications solutions, including Cisco® Unified CallManager. This paper provides a technical overview for interworking with Cisco Unified CallManager.
SUMMARY
The Cisco Unified Communications system of voice and IP communications products and applications helps organizations communicate more effectively-by helping them streamline business processes, reach the right resource the first time, and increase profitability. Although many customers take advantage of the end-to-end Cisco portfolio of communications products, some choose to combine Cisco solutions with products from third parties. For those customers whose communications strategy includes use of Microsoft Office Communicator, Cisco provides interworking with Cisco Unified CallManager.
SOLUTION
Microsoft has defined interoperability for Microsoft LCS and MOC in two distinct ways:
1. The first mode of interoperability is with MOC acting as a soft phone directly on the PC, referred to as computer mode on MOC. The end user can use media capabilities provided within the client to support both audio (through a headset) and video (through a PC camera). In this paradigm, the user can contact other end users of Cisco Unified CallManager and establish calls as well as invoke several basic call features, such as hold and transfer. This additive function of voice on top of IM is comparable to what many PC clients have been capable of in recent years.
2. The second mode of interoperability is by MOC providing direct phone control for the IP desktop phone, sometimes referred to as third-party call control. In this mode, referred to as desk mode on MOC, users still use their own IP desktop phone for media capabilities. The MOC user performs call functions by invoking the call icons on MOC, resulting in the relaying of messages to the user's unified communications solution and the actualization of the call-control function on the desktop phone.
In desk mode, the user can take advantage of core capabilities of Cisco Unified CallManager when using MOC. These capabilities include critical enterprise functions such as digit translation, routing, billing, recording, call screening, privacy, Call Admission Control, quality-of-service capabilities, signaling and media security capabilities, and numerous other call-control services.
Figure 1 shows the high-level connectivity for an end user with MOC and a Cisco Unified IP Phone connected to Cisco Unified CallManager:
Figure 1. Basic Connectivity for Cisco IP Phones and MOC to support LCS Phone Control
The following identifies the connectivity in Figure 1:
• MOC clients are registered to Microsoft LCS 2005.
• The Cisco Unified IP Phones are registered to the Cisco Unified CallManager.
• Microsoft LCS 2005 communicates with the Cisco Unified Presence Server using the Microsoft-defined Computer Supported Telephony Application (CSTA) over Session Initiation Protocol (SIP) interface.
• Cisco Unified CallManager communicates with Cisco Unified Presence Server using the Cisco Unified CallManager computer telephony interface (CTI).
A linkage between the identity of the user on the Microsoft desktop and the Cisco Unified Communication system is maintained both in the MOC and the Cisco Unified Presence Server to allow for activities on both the MOC and the Cisco Unified IP Phone to be passed transparently between the two services on the user's desktop.
BASIC CALL FLOW
The call flow diagram and description shown in Figure 2 illustrates the basic interactions between Cisco Unified Communications and Microsoft LCS when placing an internal call between two Cisco Unified IP Phones and MOC users. The two users are referenced as "X" and "Y" to simplify the call flow sequence description. The number in the call flow description corresponds to the numbered arrows in the diagram. Numerous other call flows could result in a different sequence of actions, but this representation provides a base understanding of how a MOC in phone control mode would interact with a Cisco Unified IP Phone during a call.
Figure 2. Call Flow Diagram for Cisco Unified IP Phone and MOC Internal Call
Call Flow Description
1. X's MOC signals LCS to dial Y (2510).
2. LCS signals Cisco Unified Presence Server to have X's IP phone dial 2510.
3. Cisco Unified Presence Server signals Cisco Unified CallManager to have X's IP phone dial 2510.
4. Cisco Unified CallManager signals X's IP phone to dial 2510.
5. X's IP phone goes off-hook and dials 2510 through Cisco Unified CallManager.
6. Cisco Unified CallManager notifies Y's IP phone of incoming call from X.
7. Cisco Unified CallManager notifies Cisco Unified Presence Server of incoming call for Y.
8. Cisco Unified Presence Server notifies LCS of incoming call for Y.
9. LCS notifies Y's MOC of incoming call from X.
10. Y answers the call using the IP phone.
11. Cisco Unified CallManager notifies Cisco Unified Presence Server that Y and X are on a call.
12. Cisco Unified Presence Server notifies LCS that Y and X are on a call.
13. LCS notifies X's MOC that Y is on a call.
14. LCS notifies Y's MOC that X is on a call.
15. X and Y can talk through their IP phones.
PRODUCT REQUIREMENTS
The following Cisco Systems® products are required for interoperability with Microsoft LCS 2005 and MOC:
• Cisco Unified CallManager 5.0
• Cisco Unified Presence Server 1.0(2)
• Cisco Unified IP Phones
Support for Cisco Unified IP Phone models 7905G, 7911G, 7912G, 7920, 7940G, 7941G, 7941G-GE, 7960G, 7961G, 7961G-GE, 7970G, and 7971G in Skinny Client Control Protocol (SCCP) mode and Cisco Unified IP Phone models 7911G, 7941G, 7941G-GE, 7961G, 7961G-GE, 7970G, and 7971G in SIP mode
The following Microsoft products are required for interoperability with Cisco Unified Communications:
• Microsoft Live Communication Server 2005 SP1
• Microsoft Server 2003 SP1
• Microsoft Office Communicator 1.0
• Microsoft Server 2003 Active Directory
• Microsoft Server 2003 DNS
• Microsoft SQL Server 2000 SP3*
* Required only if using Microsoft LCS 2005 SP1 Enterprise Edition
WHAT IS NEXT?
The Microsoft LCS 2005 integration of phone control through MOC and integration with Cisco Unified CallManager is the first step toward creating a truly federated service environment for joint Cisco and Microsoft customers.
Although phone control allows for MOC users to have media interoperability through Cisco Unified CallManager, it does not fully realize the capabilities of presence and the enhanced service environment within the Cisco Unified Communication system.
The Cisco Unified Presence Server has been designed to be the interface for the Cisco Unified Communication system to external desktop applications. In addition to the Microsoft phone control interface, the Cisco Unified Presence Server supports the IETF standards-based SIP for Instant Messaging and Presence Leveraging Extensions (SIMPLE) interface to allow for a true federation of IM and rich presence data.
The federation of IM and rich presence allows for a true integration of the critical communication components on the user's desktop, creating a paradigm that fosters transparent communication across a wide variety of devices, applications, and media types within the entire user's work environment-a paradigm that Cisco Systems wants to enable for all users of the Cisco Unified Communication system.
