IP Telephony Fundamentals

 Voice Over IP (VoIP)

Voice Over IP (VoIP) enables the convergence of traditional voice and data services by using an IP network

as the transport for both voice and data services. Service providers have been experimenting with

VoIP for the past five years, and now with a value proposition revolving around network infrastructure

cost savings, operational savings and new revenue opportunities, its appeal is growing. VoIP is poised

to be strategic to the overall business of both premises-based IT organizations and Managed Service

Providers (MSP).

Voice Over IP (VoIP) services:

1. Internet Telephony Services

Internet telephony refers to communications services such as voice, facsimile, and/or voice

messaging applications that are transported via the public Internet. Internet telephony is an

unmanaged service where no single provider on the Internet is responsible for end-to-end quality of

service.

2. IP Telephony Services

IP Telephony is a managed service with guarantees of service that can support full-duplex, real-time

voice communications. There are two types of IP Telephony services:

1. Premised-Based

A Hybrid PBX or an IP-PBX is installed on the premises replacing an existing TDM-PBX.

2. Network-Based

Centrex IP and Hosted IP-PBX are hosted services provided by a Managed Service


Internet Telephony Service Provider

An Internet Telephony Service Provider (ITSP) is a provider of IP-based local and long distance services.

ITSPs use the public Internet as transport network between subscribers. ITSP services can be

accessed using any broadband connection including DSL, Cable and Fixed Wireless Access (FWA).
 

Internet Telephony Service Provider (ITSP) services:

•      PC-to-PC

Internet telephony calls are made using a free downloadable client or browser-based softphone cli- ent. The client is provided by the ITSP and both the called and calling party must use the same cli- ent. Example: Skype Client

•      PC-to-Phone (PSTN)

ITSPs offer a PC-to-Phone service at a reduced per minute rate. The calling party uses a softphone client to connect or call a traditional circuit phone. The provider must install a gateway to connect the IP network to the traditional circuit network. The function of the gateway is to packatize and com- press the analog voice to be transmitted over the Internet. The gateway receives IP packetized voice transmissions from the calling party and converts them back to 64Kbps, the traditional circuit switched format.

•      Phone-to-Phone

ITSPs provide a premises-based gateway to the customer. The customer connects a standard ana- log phone set to the gateway.  The packets are transported using the public Internet to the termina- tion gateway which converts the IP packetized voice transmission back to the analog format.

An IP multimedia subsystem allows service providers to migrate seamlessly to a converged voice and data network architecture by integrating next-generation call control and existing class 5 switches. Ser- vice providers are positioned to grow the network capacity incrementally without the over provisioning typical of circuit switched network solutions.

With an IMS, a service provider is better able to control costs while maximizing its network and re- sources. Instead of adding expensive circuits and trunks, the service provider adds trunking gateways under the control of the IMS. The packet network is a lower cost infrastructure and it lays the foundation for offering IP Enhanced services as required.

Centrex IP

Service providers have providing digital Centrex to businesses for many years. Digital Centrex service provides features that are similar to those provided by a premises-based PBX. Centrex IP Centrex lever- ages systems enterprises currently have in place to reduce costs associated with buying, maintaining and upgrading telecommunications equipment, protect against equipment obsolescence, and reduce the time and expense of moving or adding phone services for a changing workforce. It unifies communica- tions that connect remote workers and locations, adding robust remote worker capabilities that help en- terprises increase worker productivity and improve customer service.

Total Cost of Ownership (TCO)

Centrex IP reduces Total Cost of Ownership by:

1.   Reduce Access Lines

Digital Centrex requires multiple digital lines installed from the provider to the business.

Centrex IP allows the replacement of these multiple digital lines with a single connection such as a

T1 or a managed broadband service.

2.   Moves/Adds/Changes

One of primary advantages of Centrex IP is that moves, adds and changes can be managed by the

customer using a Centrex IP portal. A Centrex IP portal is a web based portal that allow an IT

manager do add or change  phone feature sets.

Hosted IP-PBX

A Hosted IP-PBX is a network-based IP-PBX. With this model, service provider have an efficient, profit- able, and cost-effective way to deliver comprehensive services to their customers.

A hosted IP-PBX solution provides a customer with access to multimedia services that will improve cor- porate information productivity and enhance communications by the deployment of real-time communi- cations. These services include:

•      Number Portability

Number portability is the ability to use the same phone number for both the wired and wireless clients.

•      Multimedia Collaboration

With multimedia collaborations, employees can set up "virtual" meetings using voice or web conferencing, share files with interactive collaboration, and take advantage of rich presence and instant messaging capabilities.

•      Unified Messaging

Users have a single multimedia mailbox that gives them access to voicemail, e-mail, faxes from any wired or wireless client.

Premises-Based IP Telephony

Today, IP Telephony is utilized in small, medium and large enterprise networks. Organizations can choose to implement IP Telephony in one of three ways:

IP-Enabled PBX:

An IP-Enabled PBX supports an evolutionary approach to IP Telephony. An IP Telephony gateway is installed on  either the trunk or line side of the traditional TDM-PBX.  An IP-Enabled PBX supports both access and desktop convergence.

Hybrid PBX:

A hybrid PBX has the IP Telephony gateways integrated in the TDM-PBX. This reduces capital and operating costs of the standalone gateways. The primary advantage of a hybrid PBX is the enhanced applications such as unified messaging and contact centers

IP-PBX

An IP-PBX replaces the traditional TDM-PBX and supports an evolutionary approach to IP Telephony. The IP-PBX platform is based a client/server architecture which supports unified communications.

Unified communications is the convergence of business and IP communications applications. It is this convergence that allows IP communications to fundamentally transform existing business processes, and maximize the business value of an investment of an IP network.

Effective communications is the most critical business process that impacts employee productivity or- ganizational efficiencies, and customer service. Lack of effective communications results in:

•  Redundant communication sessions, where someone leaves multiple phone numbers and/or duplicate voice and email messages;

•  Unnecessary cell phone intrusions into client meetings, work sessions or personal time;

•  Wasted time setting up conference calls, communicating call-in information, sending and re- ceiving

documents and establishing separate sessions for voice and data collaboration;

•  Difficulty quickly mobilizing key personal because each has a different set of communication devices

and services.

These situations result in increased costs for redundant communication services, delayed responsive- ness to customers and business needs and failure to involve key people in discussions and decision making.

Anderson Jose Mariño Ortega
C.I.17.456.750
S.C.O.
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