Voice over IP is intended to replace existing analog and digital telephone applications in such a way as to be virtually transparent to the end user. This paper summarizes issues in maintaining quality in Voice over IP network transmissions and discusses how eHealth for Voice can be used to monitor these issues in the Nortel Communication Server 1000 environment.

Trucks, Inc. is a heavy duty truck part distributor serving the Atlantic region of Canada. While the database is critical to the company's business processed, it doesn't completely replace the knowledge accumulated by Parts for Trucks employees. Customers often have questions about Parts for Trucks inventory. The challenge was to make the information residing with individual employees available with the same degree of flexibility and efficiency as the information residing on Parts for Truck's HP servers. The company also wanted wireless handhelds for its staff. To understand and mitigate the risks, Parts for Trucks turned to HP Wireless and Networking consultants to pilot a wireless Cisco IP Communications Solution using Microsoft .NET enterprise technology.

Operations Support Systems (OSS)/Business Support Systems (BSS) must dramatically evolve to cope with the new shift to IP-based networks and the new services they enable. Legacy systems currently in use - the backbone of most carriers' OSS/BSS - were never designed to support the volume of information, real-time response time requirements, and time-to-market demands that the modern environment can enable. That's why new, converged telecommunications IT is needed today, based on fully integrated OSS/BSS functions. Oracle Fusion Middleware enables multiple OSS/BSS integration solutions. These solutions, based on SOA, leverage modular and standards-based components to reduce development time and improve overall ROI.

To secure VoIP, both IP and VoIP-specific security procedures and best practices must be deployed at potential points of vulnerability, where the service or infrastructure may be susceptible to known or presumed attacks.

Threats to VoIP can be grouped into three primary areas:

• Denial of Service
• Fraud and Abuse
• Data Confidentiality and Privacy

Security must be an integral element of all VoIP deployments from the beginning of the process and throughout the lifecycle management. Security is an on-going process requiring constant vigilance, and VoIP deployments must be closely monitored for new threats that could impact the service.

Download Voice over IP Security: What are the Risks and Solutions? now.

Enterprises expect voice and data network convergence to reduce management complexity, drive down operating costs, and enable more efficient communications. However, deploying a real-time application like VoIP across a data network presents unique challenges for network managers concerned about voice quality.

This "how-to" report covers five steps that are critical to ensuring quality of service when transitioning to a VoIP environment, for both the LAN and the WAN:

1. Assess Your Network
2. Select VoIP Codec
3. Obtain Metrics
4. Review Results
5. Assign the Right Class of Service

Other considerations are also covered, including optimizing WAN bandwidth, developing a LAN QoS strategy, and understanding Network Address Translation.

Download Critical Steps for a Successful VoIP Deployment now.

Coldwell Banker Elite needed a system capable of directing calls to their agents, regardless of the agent's location. Coldwell Banker Elite first considered Cisco CallManager and Cisco Unity before concluding that the Zultys products are more integrated, easier to use and maintain, and have more collaborative features. Coldwell Banker Elite selected to use the Zultys MX250 Enterprise Media Exchange and ZIP 4x4 IP telephones. Unlike similar solutions, the Zultys products are based entirely on open standards, allowing Coldwell Banker Elite to install an IP video conferencing system from another supplier. Coldwell Banker Elite can continue to build on this infrastructure as their business grows.

In many cases users of Visual FoxPro (VFP) application need to communicate (text, voice, video) over Internet. VFP itself has limited ability to satisfy those needs. There are software products available that let users do this automatically from within a VFP application. The one that the authors opted for is Skype. Like using emails, Excel or Word Automation, one can use the Skype API or indirectly the COM wrapper ActiveS to automate communication over Internet. In this paper two samples show how to use the ActiveS COM and the Skype functionality, to enable the VFP application with VoIP (Voice over Internet Protocol) and other messages handling.

Convergence of voice and data networking is no longer just a good idea; it is the future of telecommunications. Faxing technology, thought by some critics as an outdated form of business communication, is here to stay. For many businesses today, the current state of the art in fax technology is the network fax server. Whether large or small, every network fax server requires specific hardware configurations, fax hardware support, and installation, maintenance, and support of the connection between the fax server and the public telephone network. But with the wide implementation of VoIP-capable network routers and switches, a new horizon opens up for companies to leverage network fax; Fax over IP (FoIP).

Push-To-Talk (PTT) is a special feature on a mobile phone that combines the functionality of a walkie-talkie or 2-way radio with the normal mobile phone. It provides simple communication to a group of people with just a touch of a button. It is often referred to in Nokia technical documentation as 'Push to Talk over Cellular (PoC). It is based on half-duplex Voice over IP (VoIP) technology over the 2nd generation GSM/GPRS network. Thanks to the IP technology, the Push to talk service uses cellular access and radio resources more efficiently than circuit-switched cellular services, reserving network resources only for the duration of talk spurts instead of for an entire call session.

Historically, telecommunications companies have relied on what is commonly referred to as circuit-switched technology to transport telephone calls. This technology establishes a 'Permanent' connection between the calling and the called parties for the entire duration of the call. The problem with circuit-switched technology is that it requires a significant amount of bandwidth dedicated to each call, and it can only support certain types of calls. As the name implies, VoIP refers to calls that traverse networks using Internet Protocol. The voice stream is broken down into packets, compressed, and sent toward their final destination by various routes (as opposed to establishing a 'Permanent' connection for the duration of the call), depending on the most efficient paths given network congestion, etc.

NetFlow and sFlow are traffic reporting mechanisms that manufacturers have embedded into enterprise-level switches and routers. This paper describes the strengths and limitations of these technologies, and why combining NetFlow/sFlow reporting mechanisms with a distributed network analyzer is a best practice in network monitoring. Deploying a distributed analyzer that can interpret NetFlow and sFlow reporting streams gives network managers extended visibility without over-extending the IT budget.

To support mobility with Quality of Service (QoS), Mobile IP (MIP) has been found to be inefficient for both data and time sensitive services, such as Voiceover-IP (VoIP). This paper first focuses on the deficiencies of the MIP and other micro-mobility approaches found in the literature. The paper then proposes an architecture for network layer mobility support, using always on high speed access and a network-based mobility manager, termed as network server or gateway.

Voice over Wireless Local Area Network (VoWLAN) is an emerging application taking advantage of the promising Voice over Internet Protocol (VoIP) technology and the wide deployment of WLANs all over the world. The real-time nature of voice traffic determines that controlled access rather than random access should be adopted. Further, to fully exploit the capacity of WLAN supporting voice traffic, it is essential to explore statistical multiplexing and to suppress the large overhead. This paper proposes mechanisms to enhance the WLAN with voice Quality of Service (QoS) provisioning capability when supporting hybrid voice/data traffic.

While Voice-over-Internet Protocol (VoIP) on wireline network is maturing, VoIP on wireless mobile network is still in its infancy. This disparity is due to the fact that the wireline bandwidth is abundant and can be traded off for delay performance and overhead, whereas bandwidth in wireless mobile network is still a scarce resource. With the deployment of 1EV-DO revision 0 (DOr0) worldwide, the spectrum efficiency has been significantly improved. However, DOr0 still lacks of features essential for VoIP. For this reason, 1EV-DO revision A (DOrA) has been standardized in the 3GPP2 with many improvements favorable for VoIP implementation. This paper identifies challenges and explores the feasibility of implementing VoIP using DOrA.

Enterprise access security has been complex and costly. Accelerating requirements for VOIP and nomadic access using broadband and wireless are making things worse. Remote workers often feel orphaned because of technical issues while the IT group struggles to keep pace with the access complexity. Plug-and-Play and Security aren't words typically put together in one sentence. Until now. This webcast discusses Plug & Play Security - bridging Nomadic Workers for simplified networks and unmatched savings.

Ericsson Enterprise provides communication services based on mobility and broadband which has a great potential to improve productivity and enhance customer service in organizations and enterprises. Whether a person runs a small, medium or large enterprise or organization, Ericsson is committed to meeting the person's communication needs with converged and customized solutions. No matter if a person needs to purchase high-quality communications and applications as a service through an operator or improve his or her own network via CPE equipment, Ericsson's knowledge and expertise provide seamless integration through end-to-end solutions.

As one of North America's leading providers of mobile data solutions, Padcom has built a brand reputation for developing leading edge technology that consistently delivers superior performance and value. In late 2003, Padcom launched a re-engineering initiative that called for accelerated business growth and an even tighter linkage with key customers and partners. To increase their competitive advantage and help fuel aggressive growth, Padcom's leadership decided to transform their headquarters-based sales and service groups into mobile teams that would provide customers and partners with highly personalized support. Padcom was so impressed with the Avaya mobility applications that they decided to tightly link them to their own TotalRoam data networking products.

Launched as a separate company in 2000, as the technology boom was coming to an end, Avaya chose to strengthen and streamline its business, get revenues flowing and increase the resilience and agility of its operations. To do this, the independent company would have to meet the needs of its one million business customers for business communication applications that would enable them to work effectively anywhere at anytime. With a focus on the same mobility strategies prescribed to its customers, Avaya implemented IP Telephony-enabled mobility applications to equip its employees with wired and wireless mobility solutions, allowing them to conduct business seamlessly whether in the office, in a remote location or on the road.

Enna, founded in January 2005, helps companies implement this process on their own, without expensive consultants. With sales breaking all expectations and orders coming in from more than 100 companies each month, Enna needed scalability to handle the growth and flexibility to expand the office into increasingly larger spaces, while effectively managing the travel requirements of an emerging company. Enna chose HP Pavilion notebooks with Intel Centrino mobile technology because of the extended battery life and ease of connection to wireless hotspots around the world. They installed a secure wireless router in their offices and purchased Cisco handsets to connect to a VoIP phone number.

Shanghai GM is one of the three top automobile makers in China and has manufacturing plants and offices in Shanghai, Shenyang and Yantai. The competition within the automotive industry in China is extremely intense, amidst a market environment that is changing rapidly. Each leap of productive efficiency in history generally comes from the innovation of working methods. The company wireless network integrates Intel Centrino mobile technology-based notebooks with a Voice over IP (VoIP) system, enabling Shanghai GM to break through traditional communications methods to achieve seamless communications for a faster response to market changes and gaining a competitive advantage.

Bringing 3D images to life was Diginiche's forte when it opened its doors nine years ago. Its powerful 3D content won awards for organizations like the Museum of Television in Toronto, which used Diginiche's online product demonstration expertise to create a virtual museum of antique televisions. While searching for a way to make three-dimensional content useful to companies throughout a product lifecycle, Diginiche developed a new collaboration tool called Octopz. With the launch of this new tool as an Application Service Provider (ASP) model, Diginiche needed leading edge technology to ensure high levels of product performance for customers. Diginiche upgraded all of its development computers to custom-built desktop workstations with Intel Pentium 4 processor technology.

The Standard Life Assurance Company (Standard Life) was established in Edinburgh in 1825 and is Europe's largest mutual life assurance company. Standard Life's network of 40 local branches relied on Private Branch eXchange (PBX) telephony. With this outdated technology the company faced a critical decision: update the existing PBX structure or undergo an upgrade to a converged IP data and telephony network. Standard Life turned to IBM Global Services which led a team that delivered a managed solution, designed the infrastructure, managed the procurement process, installed the technology, and provided 24 X 7 onsite network support. IBM worked with Cisco Systems and deployed a state-of-the-art Internet Protocol (IP) Communications (IPC) network at Standard Life.

Wiretaps have been used since the invention of the telegraph and have been a legal element of the US law enforcement arsenal for more than a quarter century. In keeping with law enforcement's efforts to keep laws current with changing technologies, in 1994 the US Congress passed the Communications Assistance for Law Enforcement Act (CALEA). The law proved to be controversial because it mandated that digitally switched telephone networks must be built wiretap enabled, with the US Department of Justice in charge of determining the appropriate technology standards.

The Voice Over IP (VoIP) Pack includes three Excel workbooks: the Gap Analysis Report, the Vendor Selection Checklist, and the Vendor Reference Questionnaire. These interactive tools are designed to help you identify any gaps in your current telecommunications needs and choose a vendor that will best meet your requirements.

This download is for TechProGuild members only. Non-members may purchase this item from our Online Store.

This month's TechProGuild Report contains several articles on Windows Server 2003, but also includes information about VOIP and Novell's Starter Pack. This report is available to TechProGuild subscribers only.

Intel recently conducted a pilot program that integrated voice over internet protocol (VoIP) into the production enterprise environment, giving a group of employees the opportunity to experience the benefit that VoIP and unified messaging bring to the workplace. Intel IT collaborated with one of the company's business units to conduct a pilot deployment of an open standards, session initiation protocol (SIP)-based voice over internet protocol (VoIP) solution at one of its medium-size corporate sites in Parsippany.

As leaders from state and local as well as federal government bodies work to improve crisis communications preparedness and response, IP communications infrastructure and applications stand out as solutions that out-perform legacy TDM solutions in crisis situations. Survivability, interoperability and powerful new features address head on the requirements of ensuring continuity of communications and operations in the public sector. This paper analyzes the most promising developments in convergence communications and how they can fill the gaps in crisis communications.

The Japanese broadband Internet market has been increasing dramatically since ADSL (Asymmetric Digital Subscriber Line) services started in 2000, and its growth is currently the fastest in the world. IP telephony services started emerging in 2002 based on the development of the broadband Internet market. The IP telephony services market in Japan is also increasing dramatically because of its low costs and cheap usage rates. Fujitsu is committed to providing its customers with the best outsourcing services by exploiting IP telephony. This paper describes the background of IP telephony services in Japan and outlines the FENICS IP Telephony Services and some related best practices.

As the main marketing and distribution centre of the Okanagan Valley, Kelowna is one of the fastest growing communities in British Columbia. The phone systems at the City of Kelowna's 12 locations were an inefficient hodgepodge of systems from a variety of vendors. Several were failing from old age. A single unified IP telephony system from TELUS Communications Inc. featuring Cisco IP Communications has integrated all the telephony services between 12 separate locations into one system. Since turning to an integrated Cisco-based VoIP system, Kelowna has improved communications and customer service, enhanced employee productivity and operational efficiency, and lowered administrative costs.

Cisco Systems, Inc. is working with Intel Corporation, Nokia, Research In Motion (RIM) and other technology leaders to drive enterprise adoption of voice-ready wireless networks. Building upon the explosive growth and widespread adoption of Voice-over-IP (VoIP), and Wi-Fi networks, Cisco's voice-ready wireless capabilities of Cisco Compatible Extensions create the foundation for enterprise organizations that want to capitalize on these converging technologies and make voice over Wi-Fi a business reality.

If your wide area network is constructed using Frame Relay or ATM technologies, National Ethernet from THUS is a leading next-generation networking service that can offer cost savings and many service related benefits relative to your current networking. No matter whether your business is looking to reduce ICT costs and improve ROI, requires more bandwidth for a similar ongoing cost to your existing networking, wishes to gain access to multiple services delivered cost effectively down a single pipe into sites or even if your business is quite happy with its current networking, we recommend that you take a few minutes to read this paper as National Ethernet really does offer a viable alternative.

Design Within Reach deployed ShoreTel to 25 locations with 135 users. Another 40 locations and 265 users will be added in the near future.

Fast-growing Design Within Reach was opening 20 new store locations a year. Thirty-five retail stores were already open, each using separate and expensive-to-maintain Nortel phone and voice mail systems. The furnishings retailer needed a less expensive and less complex alternative for phones and voice mail. After extensively comparing VoIP solutions, Design Within Reach choose the ShoreTel solution, based on ease of implementation, centralized management, and cost-effectiveness.

The retailer deployed the ShoreTel phone systems for less than half of what it would have cost to implement its old Nortel circuitswitched phones. Not only was the ShoreTel solution easy-to-install, but also it is easy to manage and maintain. End users praise the ShoreTel system's feature set and ease-of use, and are particularly fond of the ease of four-digit dialing among offices.

Muzak is the world's leading music, messaging and sound systems provider. Muzak had a legacy PBX system that could not scale to support the company's tremendous growth. With its 200 worldwide offices using more than 30 different kinds of phones, including Panasonic, Avaya, NEC and others, the complexity and costs were staggering. They decided to transition to VoIP and looked at five vendors: 3Com, Avaya, Cisco, Mitel, and ShoreTel. Muzak chose ShoreTel for its performance, ease of use, functionality, and support. The company is now saving $100,000 in maintenance and management costs, employees are more productive and customer service has been enhanced.

The Visiting Nurse Association was faced with an unreliable, inflexible, and poorly performing telephone system which required a service provider to manage it. The VNA considered solutions from Avaya, Cisco, Interactive Intelligence, Mitel, Nortel and ShoreTel, checking references, performing site visits, and seeing product demonstrations. The decision came down to two vendors - Avaya and ShoreTel. The final consideration included ease of use, flexibility, and the ability to manage from in-house. Customer service has been dramatically enhanced and VNA is saving money, time and resources managing the system in-house.

Darby Bank & Trust deployed ShoreTel to eight locations with 160 IP 530 telephones.

Darby Bank was faced with an outdated Nortel PBX that it was quickly outgrowing. The system had reached maximum capacity at the very time the bank was continuing its rapid growth, steadily adding new branches. The IT team spent eight months reviewing solutions from Avaya, Cisco, IP Centrex (a hosted solution), and ShoreTel.

After careful consideration, seeing demonstrations, and talking to customer references for each vendor, Darby Bank chose a system from ShoreTel. They cite ease of installation and administration, performance, cost of ownership, and the robust feature set as the top reasons for going with ShoreTel.

With the ShoreTel system, Darby Bank now manages its own moves, adds, and changes, eliminating the need for costly service providers, saves $2,500 to $3,000 a month in long distance charges, has boosted employee productivity, and has significantly enhanced its customer service by enabling operators to handle incoming calls quickly and efficently.

Anythony Sylvan Pools deployed ShoreTel to 14 divsions including 50 sites and 500 users.

With its rapid growth and increasing communications costs, Anthony & Sylvan started looking at VoIP solutions. While corporate growth was a major factor, another challenge was the company's 50 locations that used independent PBXs. Anthony & Sylvan evaluated 15 different network vendors and also considered managed offerings. They spoke with customers of each vendor, watched product demonstrations, tested the solutions, and conducted extensive up-front return on investment (ROI) analyses. After this thorough evaluation process, Anthony & Sylvan decided on ShoreTel, specifically for its advanced technology, robust feature set, support for the organization's hub-and-spoke architecture, and ability to be managed in house.

The ShoreTel solution unified the 50-site company so everybody is on the same phone and voice mail system, employees enjoy four-digit dialing to reach co-workers in other locations, and calls can easily be transferred anywhere within the organization. Clients no longer need to hang up and dial another number to reach the right person, employees enjoy productivity-enhancing features, and the solution is easy and cost-effective to manage in-house.

When selecting a cabling vendor for an enterprise cabling infrastructure, one of the most difficult tasks is sorting through the vendor-provided data and getting to the information most critical to you and your network. This white paper examines several factors to evaluate when selecting a cabling partner including test reports, contractor training program, available support services and warranty claims.

This white paper introduces the topic of cabling sharing to telecommunications professionals responsible for enterprise networks. Cable sharing describes the practice of running more than one application over different pairs of a twisted-pair copper telecommunications channel thereby reducing costs, simplifying cable management, and converging applications onto one media type in commercial building environments. The growing market acceptance of fully-shielded (i.e. "category 7" or "class F") cabling systems has been identified as the primary reason why cable sharing techniques are appearing in the designs of the industry's top IT infrastructure designers and consultants. Cable sharing meets the increasing demand for high-density, low-speed application support as more and more equipment devices support IP protocol, Ethernet communication, and operation over twisted-pair cabling.

Focusing on enterprise cabling infrastructures where plans are to occupy the premises for at least 5 years, this paper demonstrates that Augmented Category 6 (6A) or higher cabling systems are the most economical solutions, providing a solid return on investment. As cabling represents 5-7% of the overall network investment, understanding the full lifecycle and industry trends will assist in your decisions. The paper compares total cost of ownership for a 24 channel cabling system ranging from category 5e through TERA category 7/class F.

Domain names records are authoritative electronic records maintained by a domain name registrar (i.e. Iron Mountain, Network Solutions, GoDaddy) that contain registrant ("Owner") contact, name server and IP address information along with creation and expiration dates. All registrars of domain names in the generic Top-Level Domains (gTLDs) are required by the Internet Corporation for Assigned Names and Numbers known as ICANN, a non-profit regulatory body) to provide a publicly accessible, searchable online database of their domain name registrant customer's names. The records are typically referred to as "WHOIS" records.

The recent economics around the globe is known to develop in direct proportional to the level of the Information & Communication Technology (ICT) infrastructure of each country. This paper includes discussion of various methods to structure the Next Generation Network at a snap and economically utilizing Ethernet based technologies, which has been and continues to be deployed rapidly. The ultimate goal is to build networks utilizing the existing investments for legacy TDM service, and at the same time be able to correspond to the All-IP networks at the minimum cost.

Nearly every company today uses Voice Conferencing in daily business to maximize productivity. There are many conferencing solutions in the market but the challenge is to integrate a scalable solution that will meet one's needs and also delivers cost-efficiency and good Return On Investment (ROI). GDS Conferencing solution is a cost effective, feature rich Enterprise Voice Conferencing solution based on native Asterisk voice conferencing application.

Here's a brief but informative white paper from Motorola that explains why wireless mesh networking makes any radio system perform better. The paper describes the military origins of mesh networks and explains why city governments are quickly adopting the technology to assist their police and other first responders. Find out why mesh networks are inherently more robust than traditional wireless networks and learn about a process called "multi-hopping" and how it supports high data transfer rates even over very long distances.

Broadband over Power Line (BPL) technology has been getting a lot of attention lately because it enables utility companies to bring high-speed Internet access to underserved areas where previously only dial-up connections were available. This Motorola white paper expands the BPL discussion by comparing medium-voltage and low-voltage BPL technologies. It explains why low-voltage BPL solutions are safer to install, cheaper to maintain, and less susceptible to interference and grid disruptions than medium-voltage solutions. The paper also introduces Motorola's Powerline LV, a flexible, affordable, low-voltage BPL solution that promises to change both the economics and logistics of reaching customers that heretofore have had no access to DSL or cable broadband services.

An IP telephony upgrade at Kia Canada continued to develop in scope as the growing auto manufacturer prepared to move into its new national headquarters, adding a network upgrade component, wireless capability, mobility concerns and Consumer Affairs functionality within a matter of weeks. They wanted something that was a lot more robust, scalable and dynamic than their legacy phone technology. A Cisco IP Communications system proved to be the only "One-stop" solution capable of dealing with the complexity of this multi-tiered project.

The GrangeNet advanced network program is a five member consortium, originally awarded a AUD$14 million, three-year grant by the Federal Government to develop and operate a high-speed backbone network linking universities and other public and private research facilities in Australia and internationally. To enable GrangeNet II to deliver the services demanded by its end users, GrangeNet engineers replaced the original core of the network with four Cisco 15454 MultiService Provisioning Platform (MSPP) systems and upgraded the edge of the network using the latest Cisco 7609 routers. The benefits of this latest technology include additional versatility, enhanced Internet Protocol multicast and IP version 6 performance, better levels of latency and jitter, and support for 10 Gigabit per second services.

Significant TCP unfairness in ad hoc wireless networks has been reported during the past several years. This unfairness results from the nature of the shared wireless medium and location dependency. If one views a node and its interfering nodes to form a "Neighborhood", the aggregate of local queues at these nodes represents the distributed queue for this neighborhood. However, this queue is not a FIFO queue. Flows sharing the queue have different, dynamically changing priorities determined by the topology and traffic patterns. Thus, they get different feedback in terms of packet loss rate and packet delay when congestion occurs. In wired networks, the Randomly Early Detection (RED) scheme was found to improve TCP fairness.

This paper presents an adaptive architecture for the transport of VoIP traffic over heterogeneous wired/wireless Internet environments. This architecture uses a VoIP gateway associated with an 802.11e QoS enhanced Access Point (QAP) to transcode voice flows before their transmissions over the wireless channel. The instantaneous bit rate is determined by a control mechanism based on the estimation of channel congestion state. The mechanism dynamically adapts audio codec bit rate using a congestion avoidance technique so as to preserve acceptable levels of quality.

This paper considers the problem of modeling TCP over multi-hop wireless networks using the IEEE 802.11 protocol. By identifying suitable regeneration instants, it is possible to apply the standard technique of regenerative processes to compute the long term average throughput achieved by a single TCP session. Simulation results show that the proposed model predicts the TCP throughput to a very high level of accuracy. The paper then discusses how to extend this model to more general situations.

Wireless VoIP, typically over 802.11 WLAN, is becoming increasingly popular, but even further elevates the challenges of delay and loss reduction. Degradation of speech quality caused by packet delay and loss of voice traffic is still one of critical technical barriers of the VoIP system. Furthermore, apart from these limitations WLANs will need to support a large number of concurrent VoIP communications since VoIP is spreading rapidly especially in public spaces. These motivations lead to study the VoIP capacity in IEEE 802.11e WLAN and to investigate increasing this capacity by reducing VoIP codec rate while maintaining an overall good quality. This paper presents an analytical model for VoIP capacity in IEEE 802.11e WLAN.