Voice Over Internet Protocol By Eric Rice

History  First telephone was patented in 1870  Rotary dialing first done in 1891  1905-Party Line  million customers  1941-Attacks on Pearl Harbor cause a percent spike in long distance nation wide

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

The Issues  Reliability  911 service availability  Voice Quality DelayDelay JitterJitter  Features  Signaling Protocol

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

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

Voice Quality  Goals Make it comparable to wire lineMake it comparable to wire line Minimize bandwidthMinimize bandwidth  Wire line Voice codec is G kbps64kbps MOS 4.3 (mean opinion score)MOS 4.3 (mean opinion score)  VoIP Voice codec G.729 8kbps8kbps MOS 4.0MOS 4.0 What?

Other Codecs  These codecs use a number of different compression algorithms to minimize required bandwidth

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

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

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.

SIP (Session Initiation Protocol)  Very simple protocol to use  Allows for advanced features to be applied by the user without a subscription

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

Features  Voic Check it online with fast-forward, rewind, and pauseCheck it online with fast-forward, rewind, and pause Check it through Check it through 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

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.

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 sid7_gci ,00.html sid7_gci ,00.html sid7_gci ,00.html  [3] Tim Lorello, Rich Tehrani (2005). E Internet Telephony, 8, (3),  [4] FCC. (2004) VoIP: FCC Consumer Facts. Retrieved April 1, 2005 from  [5] Vonage. (2005) Features. Retrieved April 1, 2005 from 