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Voice Over Internet Protocol By Eric Rice
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History First telephone was patented in 1870 Rotary dialing first done in 1891 1905-Party Line 1910-5.1 million customers 1941-Attacks on Pearl Harbor cause a 100- 400 percent spike in long distance nation wide
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History cont. 1949-the average calls placed in a day reach 180 million. 1975-there are 140 million telephone lines in the US and AT&T controls 85% of them 1993-AT&T offers Caller ID 1995-Vocal Tec release first VOIP software 1996-First cable modem service offered by Roger Communications 2001-Vonage founded March 2002-Vonage initiates service
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The Issues Reliability 911 service availability Voice Quality DelayDelay JitterJitter Features Signaling Protocol
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Reliability The current standard Five-nines (5 min of downtime a year)Five-nines (5 min of downtime a year) “Networks go down all the time” High Internet Traffic
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911 Availability Currently address information is linked to a number Due to VoIP portability, locations are not defined In order to receive 911 service it must first be set up Mobile phones have this same problem Alternate solutions include developing new port mapping technologies Using GPS to locate callers
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Voice Quality Goals Make it comparable to wire lineMake it comparable to wire line Minimize bandwidthMinimize bandwidth Wire line Voice codec is G.711 64kbps64kbps MOS 4.3 (mean opinion score)MOS 4.3 (mean opinion score) VoIP Voice codec G.729 8kbps8kbps MOS 4.0MOS 4.0 What?
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Other Codecs These codecs use a number of different compression algorithms to minimize required bandwidth
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Delay Delay is measured using Round Trip Time Keep delay less then 300ms If greater then 300ms may seem like making an international call: take this situationIf greater then 300ms may seem like making an international call: take this situation Person A Person B A Speaks B interrupts and starts talking A hears B’s interruption and stops talking B stops talking because they think A ignored the interruption B hears A and stops talking Uncomfortable silence A starts talking B starts talking A hears B and stops B hears A and stops
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Jitter Occurs when delay changes If the delay increases and decreases sporadically it makes conversations sound choppy RTP (Real Time Transport Protocol) Adds a sequence number and a time stamp to UDP packets This allows for delay and jitter to be calculated accurately
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Solutions to Jitter and Delay Add bandwidth to the entire Internet We find ways to use up all the bandwidth we are givenWe find ways to use up all the bandwidth we are given Reserve bandwidth on the routers it uses This would not be fair to the rest of the packetsThis would not be fair to the rest of the packets Temporary solution is to simply route the calls through the current switch network.
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SIP (Session Initiation Protocol) Very simple protocol to use Allows for advanced features to be applied by the user without a subscription
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Features Cheaper Service No long distance charges Caller ID Call Forwarding Call Screening Users can do other things than just block a callUsers can do other things than just block a call If Kitrek were to call, I would be able to forward his call to an insult hotlineIf Kitrek were to call, I would be able to forward his call to an insult hotline
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Features Voicemail Check it online with fast-forward, rewind, and pauseCheck it online with fast-forward, rewind, and pause Check it through emailCheck it through email Check it over the phoneCheck it over the phone Require unknown callers to provide an intent for calling If a telemarketer calls they would have to tell what they wantedIf a telemarketer calls they would have to tell what they wanted It would then be displayed on the caller IDIt would then be displayed on the caller ID
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Conclusion VoIP is a technology which will eventually replace the current Switch network. With new and fully customizable features, along with cheaper service and no long distance charges. We can expect to see VoIP much more in the future.
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Resources [1] Danial Collins. (2001). Carrier Grade Voice Over IP. New York. McGraw-Hill. [2] John Shepler. (2005). The Holy Grail of five-nines reliability. Retrieved April 1, 2005 from http://searchnetworking.techtarget.com/generic/0,295582, sid7_gci1064318,00.html http://searchnetworking.techtarget.com/generic/0,295582, sid7_gci1064318,00.html http://searchnetworking.techtarget.com/generic/0,295582, sid7_gci1064318,00.html [3] Tim Lorello, Rich Tehrani (2005). E-9-1-1. Internet Telephony, 8, (3), 40-41. [4] FCC. (2004) VoIP: FCC Consumer Facts. Retrieved April 1, 2005 from http://www.fcc.gov/cgb/consumerfacts/voip.pdf http://www.fcc.gov/cgb/consumerfacts/voip.pdf [5] Vonage. (2005) Features. Retrieved April 1, 2005 from http://www.vonage.com/features.php http://www.vonage.com/features.php
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