One of the most recent and exciting technologies today is Voice over IP (VoIP). This technology is a form of telecommunication that allows data and voice transmissions to be sent across a wide variety of networks. VoIP allows businesses to talk to other branches, using a PC phone, over corporate Intranets. Instead of using public phone lines, VoIP creates an alternative to paying long distance phone bills. Using this new technology has many ideal advantages. It is cost effective, it allows easier communication, is great for international use, and it can be very useful for large corporations. However, there are also some negative factors of VoIP, such as voice clarity and transmission delays. In time VoIP will become a new way to communicate and will have a large effect on University, business, and personal communications.
VoIP (Internet Protocol) technology unites the telephony and data worlds. VoIP allows phone calls, faxes and voice traffic to be relayed over corporate Intranets or at home across the Internet/Intranet. VoIP technologies convert digitized voice into data packets that are encapsulated in Internet protocol. This form of data is then routed between multiple DVFG’s, providing toll-quality voice, directory services, and complex voice quality assurance capabilities.
VoIP technology was first used for conference calls and voice communication over the Internet. When using this type of operation, significant delay, delay variation, and IP packet loss are not uncommon. (Buss. Comm. P.1.) In the Internet the user can not control these factors, and generally the infrastructure is typically not in place to allow control by the Internet Service Provider. This lack of control causes unclear and inaccurate voice messages to be received. VoIP products are therefore “unable to ensure the high voice quality a caller is used to when using the public switched phone network (PSPN).” (Busi. Comm. P.2) Since the quality of everyday phone calls is significantly better than VoIP via the Internet, few PC users have converted to VoIP products outside the business environment.
Current VoIP technologies aim to serve larger organizations and businesses in everyday operations. “The latest generation of VoIP products incorporate new technologies to address quality of service issues and allows companies to use their existing phone network to connect from a PBX, key system, or desktop phone directly into a VoIP card installed in a single PC Gateway.” (Free p.1) These new technologies are being used on corporate enterprise networks, allowing companies to communicate to other branches of operations around the world. Companies that use VoIP technologies escape paying large long distance bills.
Private Intranets and similar type of networks provide a more supportive infrastructure for VoIP than the Internet. Typically Intranets only communicate between two locations at a short distance, limiting the risk of delay and IP packet loss. Therefore Intranets generally have PSPN quality acceptable by most business standards. Intranets are also easier to configure which enable the data packets to be sent through a fewer router hops creating a “clearer” line than the Internet. Router priority protocol is also used to guarantee the data packets pass over a delay-free infrastructure to ensure PSPN quality. Due to these factors, quality similar to a “Public Switched Phone Network can currently only be guaranteed over corporate Intranets or enterprise networks.” (Busi. Comm. P.2)
Making Voice over IP function efficiently in a corporate enterprise network requires adequate bandwidth allocation and management. For each call to be sent across an IP network, 17Kbps is needed of the total bandwidth. If properly designed and operated a company’s network can use a 56 or 64 KBPS link to simultaneously share several voice calls and data traffic without any delays or problems. Whereas when using the Internet, Providers such as America on Line (AOL) handle too much Internet traffic and rout transmissions too many times to provide a clear and precise connection. In larger organizations where a large amount of data is carried across a network, Voice over IP would need a separate infrastructure in order to be utilized. Especially in companies where up to 50 phone lines can be used simultaneously an Intranet type of infrastructure will be needed to process the calls with PSPN quality.
Voice over IP Telephony has been fairly popular in last few years and there are several reasons carriers should be interested:
4 First, it offers a short/medium term arbitrage opportunity. This means that for example it is cheaper to make an IP telephony call than a circuit call because the operators avoid paying interconnect charges.
4 Second, because of engineering economics: A circuit switched telephony call takes up 64 KBPS while an IP telephony call takes up 6-8 KBPS.
4 Third, it offers exciting new added values in the long term. Such value added opportunities include: IP multicast conferencing and telephony distance learning applications, phone directories and screen popping via IP, and “voice web browsing” where the caller can interact with a web page by speaking commands.
4 Lastly, IP telephony gives carriers ability to manage a single network handling both voice and data.
IP telephony will also create great demand for new services. It will allow people to control different media and different types of terminals such as PC and fixed phone straight from their web browser. Users will be able to route home calls to a GSM phone or Centrex voice mail, they will be able to make conference calls from home, and they can even ban children from entering certain audiotex services.
In today’s times the motto seems to be “get more for less”. Cost is a major consideration in the idea of IP telephony. “Providers are trying to offer depth and breadth of service offerings that let them capture the most revenue from customers and new prospects”, Forester Research analyst Jim Freeze. IP telephony has a considerable cost advantage over the public switched telephone network simply for the fact that IP telephony providers do not have to pay contributions to local telephone companies to support local service. As you can imagine consumers are ecstatic about this innovation. They can use an Internet and a PC to dial there friends anywhere in the world and talk as long as they wish without worrying about enormous long distance charges. The real cost benefit when using IP telephony is in the business world. Instead of paying per-minute usage rates, one can use the Internet to connect the offices. Rather than paying long distance toll charges, one has the choice of buying guaranteed services from an Internet Service Provider and then routing calls over that connection. If a corporation applies IP telephony to field offices they can integrate users into their corporate dialing plan, voicemail system, and other services for a reduced cost. An actual numerical example can go something like this: Your company spends nine cents a minute on office to office calls each month. By integrating VoIP you can cut those charges by almost half to five cents a minute. This is definitely a positive factor in favor of VoIP.
One great case and example of how VoIP has worked in the working world is the Prince Law Firm. Warren Prince has seven law associates and five offices located all over Pennsylvania. Being not only a lawyer but also a computer wizard he implemented a Voice Over network that averts long distance costs and makes full use of staff. This program has allowed him to operate his business and to expand it at a lower cost. His system includes: A VoIP Internet hop across a LATA (Local Access Transport Area) where he receives free long distance calling. Everything that goes on in the office on a typical day that can be digitized is turned into in electronic file to be sorted, routed, sent or stored in the network system. Such items as invoices and mail can be scanned and turned into e-mail and spread within the network. Efficiency and reduction in cost in the business world is what this example portrays.
VoIP is a growing technology and very practical for larger companies and organizations. There are many products available on the market that manufactures hardware and software that enable VoIP to be used. Lucent Technologies, Micom, Nuera Communications and Selsius Systems are just a few of the companies that produce VoIP products. Current products include VoIP cards that are designed to be installed in all PC workstations within a company that connect to a network. The VoIP card “provides the telephony interfaces to the phone equipment and digitizes and compresses the voice.” (Edwin p.1)
The transmitted message after being converted to encapsulated IP packet is sent to a PC gateway. These gateways range in price and features depending on what type of infrastructure and connection is used. Lucent Technologies currently manufactures the ITS-E (Internet Telephony Service—Enterprise model) which is based on a Windows NT Server. (Edwin p.2) The unit has either an 8 port analog line or a T1 interface capability. When using the T1 capability the gateway can handle up to 24 calls relaying voice simultaneously. To set up the option of using a T1 connection, Lucent Technologies will send out a technician to tune the system and make it operational. This service starts at $500 and varies depending on time and the complexity of the network.
Other products are available that enable a central site to manage many gateways via the same IP network. Nuera Communications F200ip is one that has these advantages and when fully loaded can handle up to 30 channels of communications at one time. Products such as this can range from $12,000 to $25,000, often making it too expensive to average size organizations budget. According to Business Communications Review, the F200ip is worth the price if all its capabilities can be utilized. (Edwin p. 4)
Another product is Startup StarVox Inc. who is adding a little niche of their own to VoIP. It will be the offering the first VoIP gateway with an intelligent caller ID. This lets data and voice travel over an internal voice network. This will make it easier to provide IP voice and data capabilities to remote users. It will also be easier to interconnect different phone systems. The StarGate Server will use internal directory services to provide users with information about interoffice calls as they come in. As a person is being called they receive a computer screen-pop saying, "who is calling." The information includes location, title, E-mail address, a picture, and a text message from the caller. The caller gets a screen-pop when picks it up or to let them click on the voice-mail and callback options. StarVox is the first company to focus on real applications for integrated voice and data over an IP pipe.
Another industry guiding the entrance of VoIP is the cable modem services. This is their new weapon to combat against the digital subscriber line (DSL). “The combination of voice and data capabilities in a single cable modem is a significant advance”, said Jim Wahl, an analyst with The Yankee Group in Boston. Motorola will be the company to demonstrate a prototype cable modem that can handle IP voice. The box is known as an integrated multimedia terminal adapter (MTA). With this, cable providers will be able to offer voice and data services to homes over the same coaxial cable that delivers television service. Qualcom, which is a wireless hardware maker, is testing this new idea out. Their goal is to save money over long distance voice and traditional circuit-switched local service.
The main problems with the VoIP technology as it is today are the interoperability, security, and bandwidth management issues. All three of these are major stumbling blocks that will keep VoIP technology from being implemented immediately into large corporations; until these problems are fixed, standard PBX’s will remain the norm for voice communications.
All three problems arise from the lack of a single standard being adopted by the software and hardware vendor companies. While the ITU-T’s Recommendation H.323 is gaining wide recognition as the standard to follow, many vendors have yet to completely comply with all the guidelines and suggestions contained within. Despite the fact that Recommendation H.323 is not only for VoIP technology (it also applies to IPX and AppleTalk), it is the most suitable and slowly second and third generation technology is adapting this as the guideline to follow. Recommendation H.323 is a modular version of the H.320 multimedia-over-ISDN specification, and is especially designed foe packet-based networks, making it ideal for VoIP.
The other strong point of H.323 is that it is extremely flexible when combining an existing voice network to VoIP equipment. It defines several different nodes most commonly found in voice networks (terminals, gateways, and gatekeepers).
The problems inherently found in companies that attempt to install complete VoIP networks is a further reason for implementing only select components that are H.323-compliant, whenever possible. The reason is that the technology and equipment for complete VoIP networks is not yet operational at a feasible level.
One of the major challenges is the lack of bandwidth management of current networks employed within most companies. The bandwidth requirements for large companies or universities are much larger than for small companies and departments. With only one codec, the G.711, being recommended by H.323 as compatible with all vendor products, the possibilities are very limited. Because codecs are the required component for converting analog waves into packets of digital signals, the frame relays of large companies are over taxed. This is due to the high KBPS requirements of the G.711 - 64 KBPS versus the much lower KBPS of other codecs.
Although there are other codecs which would only take up 8, 6.3 or even 5.3 KBPS of bandwidth on each end, these other codecs are not compatible with every vendor and thus making the implementation of these codecs impossible. The only solution is to only use products form one vendor, and this is also not a viable alternative. Therefore the H.323 only recommends the G.711 codec due to its interoperability with all vendors. The end result is a trade off between a working system that is very slow and taxing on frame relays or a very limited option of products and a codec that uses less bandwidth. Even if a company does use the G.711 codec it is only operational if the company uses prioritization services at not only the physical but also the data-link and network layers of the entire network. Problems that arise from using switches instead of hubs, and having to incorporate something like 802.1Q and 802.1p within the Ethernet. Anther option is to use sound suppression within the end-point equipment, mainly headsets and directional microphones, but this is only a small factor as most noises would still be picked up. Thus the reliance upon the G.711 makes large-scale implementation of VoIP technology a non-option of large corporations at this time.
Companies also face problems with interoperability when attempting to use PC-based products such as Microsoft Corp.’s NetMeeting or VocalTec Communication’s Internet Phone. While these and other similar PC’s are a new and exciting technology, the current generation is hardly up to par. Not only do codec have trouble running on a PC that is also trying to process” interrupts, run programs, and manage the operating system overhead” (Hall 42), but these PC’s are also susceptible to system freezes and crashes just like normal PC’s. Another consideration is that there is not yet available any software base system that can process audio quickly enough to be cost efficient fore businesses. The last alternative is the new sound cards with “on-board codecs [that] perform faster processing and are of much higher quality” (Hall 42). Again the problem arises of this new technology just getting started and as yet the performance does not make them a viable solution, yet, although the advances being made by such companies as PhoNet Communications and QuickNet Technologies are promising.
Other problems with VoIP as it exists today revolve around the issue of security - a high priority for and company or university who relies on its computer networks for quick access to private or sensitive materials. Currently encryption and authentication of user access is only a recommendation by H.323. What this means is that any H.323 aware user can tap into any conversation on the system. And an employee or any outside person can monitor every conversation with access without ever having to leave his or her desk.
Another security issue arises if a corporation uses VoIP technology for a remote access location. This is one of the main uses for partial VoIP implementation today, but it is also a serious security risk because of problems with firewalls. Currently H.323’s firewall negotiation mechanisms require direct access into the corporate network. A blatant violation of most corporations’ security requirements is the call-set up of H.323. This part of the recommendation requires every node on a network to monitor for any port number above 1,024. In other words a corporation would have to open its entire network up to all UDP and TCP traffic.
The solution is to contain all H.323 traffic within one region and then use a voice trunk to connect traffic between the isolated region and the rest of the network. The other viable solution is to use an H.323 aware firewall. A product that is becoming more widely available as this new technology continues to address the initial problems inherent in the first generation design. Security is one issue that most corporations must take into account when implementing new communication systems and is a good reason for a gradual switch between POTS and VoIP technology.
AT&T chairman and CEO Michael Armstrong a few months ago announced his commitment to make use of VoIP technology by the company. While he realizes that advancement s are needed still, he has already begun to implement trial runs of the current VoIP technology in several corporations in different countries.
What AT&T has done is to implement VPN (virtual private networks) technology in an effort to offer price cuts and to begin establishing a “global clearinghouse” (Gerwig 8). The plan is to allow ISP’s to offer IP telephony to 140 countries with AT&T overseeing the routing service. For such a large and influential company to jump on the VoIP bandwagon is good news for this newest filed of communication services and is a sign of bigger and better things to come.
While the service is currently in the first trial stages, it is necessary to begin slowly. As previously mentioned a full-scale implementation of VoIP technology faces several hurdles before it will be feasible for full-scale public and private usage. The point of this early test run is for AT&T to test push the vendor companies to further their research and also to begin working on customer acceptance. The main problem being that this technology is not yet comparable to circuit switched networks. Armstrong maintains that security and quality control are the main issues that this trial run is working towards achieving.
Due to the inadvisability of a full sale implementation of VoIP technology, the advice of H.323 and other authorities at the present time is for companies to partially implement this new communication technology. This can be done in different ways depending upon the setup and demands of a company on an individual basis.
4 If a company is going to implement the VoIP system in their headquarters, it is only recommended for sites with 100 or less users. Anything over this would result in problems from interoperability to a lack of bandwidth management. If a company were to even attempt to design and implement the infrastructure required to handle the demands of a G.711 codec based VoIP system, the cost alone would be the major deterrent. For much less a comparable PBX system could be implemented.
4 Another opportunity for companies to pilot VoIP technology is in the remote or branch office. These locations often have smaller amounts of traffic as well as fewer users. The system needed to support a smaller group would therefor make the VoIP technology cost feasible. Then the main advantage of the VoIP technology - the avoidance of long distance toll charges for calls to the home office - can be utilized. The best set-up for the remote office then is to buy services from an ISP and then route the VoIP calls over that connection, thereby avoiding the toll charges of long distance calls or the high cost of buying a companies own dedicated network.
4 The last recommended use for VoIP by corporations with the current technology available is for the telecommuters or home office employees. Although the demands of the telecommuter are high, they require both a data and a voice line, which makes for high costs, the use of VoIP can more easily integrate them into a companies network. By simply providing a single data circuit and the necessary H.323 equipment they can become integrated into the whole telephony system and enjoy the advantages of the personnel who work at the home office. Again the problem of bandwidth management poses a problem. Unless the telecommuter has enough bandwidth to move VoIP traffic and still handle the routine functions calls may get lost in the middle of large database queries and other common problems related to data related files. The other drawback is that if a large file is being accessed then the telecommuter may not receive notice of incoming calls before the caller hangs up or gets disconnected. All these problems are the result of the G.711 codec not efficiently handling bandwidth, but future generations may see this problem resolved.
With the advent of Internet telephony the idea of Voice over Internet Protocol (VoIP) has begun to gain notice not only from companies and universities, but also from private individuals. The main reason being that VoIP allows for telephone calls to be made over the internet, thus eliminating the cost of long distance phone charges that the phone companies charge of long distance phone calls. While this money saving technology is good news for small and large consumers, there are still many problems that have to be worked out before this becomes a viable alternative to everyday telecommunications. Thus, as more technology is developed and price for VoIP products become less expensive, VoIP will become a reality for everyone. VoIP technology will revolutionize the telecommunications industry and if used properly can create many positives for companies and private individuals alike.
“Free Business to Business Long Distance.” Jmbest.net/private.htm JM Best. 7 Dec. 1998.
Hanson, Lesley “The Changing Face of Voice Communications.” Itweb.co.za/office/Micom. Telecom newsletter 6 Dec. 1998.
“Internet Telephony Overview.” Intelliswitch.com/it.html Intelli-switch 7 Dec. 1998.
Mier, Edwin E. “Voice-over-IP Gateways: Sounding Good.” Bcr.com/bcrmag. Feb. 98.
Business Communications Review. 6 Dec. 1998.
Stevens, Debbie “ Business Communications Take a New Direction.” Itweb.co.za/office/Micom/wpbusi.htm 7 Dec. 1998.
“Taylor, Steven A. “Frame Relay Voice: Compelling Economics for Immediate Implementations.”nuera.com/Tech/whtpaprtext.html 7 Dec. 1998.