Published on March 20, 2011
W will talk about: e• Telephone.• Internet Protocol.• Voice over Internet Protocol. 1. Its uses. 2. Its benefits. 3. Challenges.
• Telephone is a telecommunications device that transmits and receives sound.• It converts the sound waves to electrical signals, which are sent through the transferring medium to the other phone, where they are converted back to sound waves.• Telephones are a duplex communications medium, meaning they allow the people on both ends to talk simultaneously.
• Protocol is how some thing is done in given steps.• Internet Protocol is how data is transmitted through the internet.• Each computer has it’s own IP address so data is sent directly to it’s address.• Packets is how data is transferred through the internet.• Each part is sent through the internet as one packet.• Packet is a data with some other headers like source IP address , destination IP address & packet size.
• Is one of a family of internet technologies and transmission technologies for delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks.• Is a technology that allows you to make voice calls using an Internet connection instead of a regular phone line.• VoIP is the technology in which the analogue voice signal is digitized and becomes binary numbers in order to be transferred by the IP protocol.
VoIP can beimplemented in several ways:
1. Dedicated VoIP phones connect directly tothe IP network using technologies such aswired Ethernet or wireless Wi-Fi..
2. An analog telephone adapter is a deviceused to connect one or more standard analogtelephones to a digital telephone system.
• A softphone (Skype) is application software installed on a networked computer that is equipped with a microphone and speaker.
Why we use VoIP?!
• Because of the bandwidth efficiency and low costs that VoIP technology can provide.• VoIP allows both voice and data communications to be run over a single network, which can significantly reduce infrastructure costs.• VoIP devices have simple user interfaces, so users can often make simple system configuration changes.
Benefits of VoIP
1. Operational Cost• VoIP can be a benefit for reducing communication and infrastructure costs. Examples include:• Routing phone calls over existing data networks to avoid the need for separate voice and data networks.• Conference calling, IVR, call forwarding, automatic redial, and caller ID features that traditional telecommunication companies normally charge extra for, are available free of charge in VoIP.
2. Flexibility• The ability to transmit more than one telephone call over a single broadband connection.• Location independence. Only a sufficiently fast and stable Internet connection is needed to get a connection from anywhere to a VoIP provider.• Integration with other services available over the Internet, including video conversation, message or data file exchange during the conversation.
Challenges of V oIP
1.Quality of service• It does not provide a network-based mechanism to ensure that data packets are not lost, or delivered in sequential order.• A VoIP packet usually has to wait for the current packet to finish transmission, although it is possible to abort a less important packet in mid-transmission.
2. Power Failure• Telephones for traditional analog service are usually connected directly to telephone company which provide direct current to power independently of locally available power.• IP Phones and VoIP telephone adapters connect to routers or cable modems which typically depend on the availability of mains electricity or locally generated power.
3. Emergency calls• The nature of IP makes it difficult to locate network users geographically.• Emergency calls, therefore, cannot easily be routed to a nearby call center.• Sometimes, VoIP systems may route emergency calls to a non-emergency phone line at the intended department.
4. Security• VoIP telephone systems are susceptible to attacks as are any internet-connected devices. This means that hackers who know about these vulnerabilities can institute attacks, harvest customer data, record conversations.• To prevent the above security concerns government and military organizations are using Voice over Secure IP (VoSIP), Secure Voice over IP (SVoIP), and Secure Voice over Secure IP (SVoSIP) to protect confidential and classified VoIP communications.
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