Voice Over Internet ProtocolVoip Essay Research Paper — страница 3

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Level 3 is another player in the Pure VoIP field. Level 3 doesn’t use compression on its network for voice calls. That allows a packet to travel from one end of the country to the other in less than 90 msec., which matches PSTN quality. Along with companies like Qwest, Level 3 is pouring billions of dollars into developing and deploying cutting edge backbones for offering IP based voice, data, and video services. Government: Another player to this game is of course the Government, Government at every level. Many questions are arising in their eyes. What defines an Internet call? How will local governments react to losing a large source of revenue that was being generated from local telephone calls? Some foreign governments are already taking a stand against VoIP. Pakistan’s

Ministry of Posts and Telecommunications, due to losing revenue to VoIP, has banned voice over the Net. The Government players will ultimately have the most profound effect on how this technology plays out. This player needs to be closely watched. ADVANTAGES AND DISADVANTAGES OF VoIP There are numerous advantages cited for VoIP. They are as far reaching as they are controversial. Some of the advantages to the business user included: Cost reduction, simplification, consolidation, advanced applications, backward compatibility, new revenue streams, and more efficient infrastructures. Cost reduction will be seen across the board from cheaper to “free” long distance calling to less investment in hardware and software. This will be extremely beneficial to those companies with

international markets. It will be more cost effective for a business to maintain one network than two separate ones. Standardization of a voice/data network will reduce total equipment costs as well. Network managers will have to assume the role of managing voice packets and protocol as well as data. VoIP is backward compatible with video conferencing and other applications already in place in many organizations and it supports multimedia applications and multiservice applications, something the traditional phone service cannot compete with. There are several obstacles that VoIP must overcome. Latency is one of the largest obstacles facing this technology. Latency is the delay or time between packets that have the same destination and compose the same message. If there is latency

between voice packets this will cause the conversation to be choppy and unintelligible. VoIP expends and average of 40 to 60 msecs of delay per gateway. That kind of overhead gets noticed pretty quickly, especially when you are traversing multiple gateways. Interoperability is another key issue. The best way to date for voice traffic to travel from an IP network to PSTN is Media Gateway Control Protocol (MGCP). This protocol allows an ISP’s switch server to manage and control SS7 switches on a PSTN, and the gateways on an IP network. Security, reliability, and training are also drawbacks too fully integrating VoIP within an organization. Security is an issue with the H.323 protocol. H.323 is a protocol used for voice over Internet protocol. Compared to more mature services such

as FTP, Telnet, and HTTP, H.323 is relatively new, thus many proxy servers do not support it. Users making calls on this protocol must be placed outside of the corporate firewall. Many people have become accustomed to their phone with all its fancy features. Call waiting, holding, transferring or redirecting calls are options not available with todays software. Finally, reliability remains a major obstacle. When it comes time to have to reboot the computer after it locks up, that lost call was hopefully not an important client. WHAT’S NEXT As with all technologies, new products and systems are emerging everyday to help alleviate some or all the disadvantages of incorporating VoIP. New protocols are emerging as well. Session Initiation Protocol (SIP), Media Gateway Control

Protocol (MGCP), and Simple Gateway Control Protocol (SGCP) are protocols designed as alternatives to H.323. They are designed to reduce bandwidth overhead, security issues, and time sensitivities not covered by H.323. Level 3 and a group of other next-gen telcos has developed a protocol called Internet Protocol Device Control (IPDC). This protocol was designed for use between centralized switches and IP-based gateways, providing management and integration on a very large scale. By working on the problems of latency, security, reliability and manageability, VoIP will be more poised than ever to begin its global roll out. CONCLUSION The VoIP market is turbulent and characterized by a variety of approaches. These approaches range from the desktop to the carrier switch to the