Voice over IP (VoIP) refers to telephony technology that transmits voice communications across a network utilizing IP standards. A primary benefit of Voice over IP is its ability to help reduce costs because phone calls travel across the data network rather than the phone company's network. IP telephony encompasses the full suite of Voice over IP enabled services such as the interconnection of phones for communications; associated services including billing and dialing plans; and basic features such as conferencing, call transfer, forward, and call hold. These features might at one time provided by a Private Branch Exchange (PBX).

Voice over IP is the basis for more advanced unified communications applications. Cisco's Unified Communications system of voice, video, mobile, and IP communications offerings provides the technology for building a centralized converged system that can manage multiple types of traffic simultaneously. Cisco's solution provides this functionality while maintaining an outstanding degree of network availability, QoS, and Protection. Major benefits of Cisco's telephony product line include:

• A flexible, interoperable migration strategy that enables you to select IP Communications solutions that meet your existing need, while providing a smooth path for expanding IP deployment
• QoS mechanisms that provide high voice fidelity through tight management of latency, drop out, and distortion
• Network management technologies that provide system administration, operations, troubleshooting, configuring, problem tracking, and device control

The architecture of Cisco's IP Telephony solution is composed of call endpoints, call-processing agents, and telephony applications.

Communications Endpoints
A call endpoint is a user device, and can be a physical phone or a software phone program that runs on a personal computer. In the Internet Protocol world, every phone is Ethernet connected. IP phones offer all of the features that an ordinary telephone provides. IP phones can also provide additional features such as the ability to connect to the web or host useful software. Cisco VoIP phones include the Cisco 24-button Unified IP Phone 7931G, Cisco's Unified Wireless IP Phone 7921G, and the Cisco Unified IP Phone 7985G video phone.

Within a Cisco Internet Protocol phone network, you can also use the Cisco IP Communicator, a desktop computer-enabled telephony application. When use the Cisco IP Communicator remotely, you take your virtual office with you and also have access to the familiar phone services you have in the office. System managers can set up Cisco IP Communicator the way they do any other Cisco IP Phone, significantly streamlining IP telephony management.

Unlike ordinary PBX systems, in a Cisco IP Telephony network you can implement virtually instantaneous moves, adds, and modifications. You merely take the VoIP handset to its new location, attach it to the Ethernet connection, and the IP phone announces itself with Cisco Communications Manager (formerly CallManager). All client permissions and settings are programmatically replicated, doing away with the expense and hassle of sending technicians to rewire connections. Another helpful capability is extension mobility, which allows you to sign into any Cisco IP phone and receive your own phone ID and privileges.

Call-processing Agents
The call-processing agent is the center of Cisco's IP Telephony solution. To address your business requirements you can elect to deploy a centralized call-processing model, a decentralized design, or a mix of the two. In a centralized approach, Cisco Communications Manager extends corporate phone features to packet products such as VoIP phones, media processing devices, Voice over IP gateways, and multimedia applications across the environment. Cisco Communications Manager supports extra mixed media services including unified messaging, video conferencing, and collaborative customer communication networks.

When a centralized Cisco Communications Manager cluster also handles call management for users at distributed locations, administrators can help ensure non-stop phone operation through Cisco SRST, a Cisco IOS Software image for routers. If a WAN link fails, Cisco Survivable Remote Site Telephony incorporated in the router provides basic Cisco Communications Manager capabilities until the connection is returned.

For small networks or remote small enterprise branch locations that do not require the complete, enterprise-class functionality available from Communications Manager, Unified Communications Manager Express, formerly CallManager Express, provides a cost-effective alternative that handles the needs of locations with up to 240 workers. Since Unified Communications Manager Express is embedded in the Cisco IOS Software running on a Cisco router, smaller organizations are able to rapidly and simply implement a combined voice and data solution.

IP Phone Applications
Under Cisco's Unified Communications platform, IP phone applications are physically independent from the call- and voice-processing mechanism, and they may be anywhere within the network. A cohesive connectivity framework offers an open platform for feature-rich applications, and acts as a firm basis for downstream convergence-based applications.

Cisco cooperates with leading IT industry partners to offer a broad range of independent Internet Protocol phone applications and devices. Cisco also supports the ability to create and manage specialized applications.

Cisco's Unity Connection Services for Integrated Messaging
Cisco's Unity solution offers advanced voicemail plus integrated messaging options that seamlessly operate with Exchange, Domino, and Groupwise. Cisco Unity scales to meet the requirements of large enterprise organizations and provides powerful migration utilities and a wide array of efficiency enhancing features.

The Cisco Unity system supports both Cisco Communications Manager and leading PBX systems to allow your business to move up to IP telephony at your own pace and preserve your current infrastructure investments. The product suite also offers a variety of networking modules that support sophisticated message interchange with popular voice-mail systems. When you are upgrading to the Cisco Unity solution, these modules promote a smooth transition by offering you the ability to exchange messages with internal subscribers who reside on a different messaging platform.

Unity Connection combines unified messaging, voice recognition, and call transfer rules into an easy-to-manage system for mid-size companies with as many as 3000 workers. For companies with 500 users, Cisco Unity Connection is offered as a one-server option with Unified Communications Manager Business Edition.

Cisco Unity Connection is a feature-rich product built on a platform that is easy to deploy and support. With Unity Connection users can access voice messages via Cisco Unified Personal Communicator, use the display on their Cisco VoIP Phone to view, search, and sort voice mail. and even use the voice recognition capability of Unity Connection to connect to and participate in Unified MeetingPlace Express conferences. Unity Connection also offers resilient automated attendant features that include smart call routing and easily personalized call screen and message alert options.

Cisco Unity Express, available in certain Cisco Integrated Services routers, offers affordable voicemail, integrated messaging, interactive voice response, and automated-attendant services for small to medium businesses (SMBs) and enterprise satellite offices with up to 250 workers.

How Progent's Consultants Can Help You with Cisco's VoIP Technology
Progent can provide a Cisco Certified Internetwork Expert or certified CCNP to help you to implement and maintain Cisco IP telephony products. Progent's programmers can create specialized IP telephony applications that will enable your organization to integrate the capabilities of Cisco Unified Communications Manager into your company processes for enhanced productivity. Progent can evaluate your existing network and Internet connectivity architecture to determine whether your environment is configured to accommodate Voice over IP, help you to choose and deploy Cisco hardware and software that make sense for your current needs and downstream growth strategy, and interface your Cisco VoIP solution with technology from other vendors.

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