??ad??t?a?? ???ef???a

1
??ad??t?a?? ???ef???a
Ge?e?at???? ??µ?t??? ?p???f??? ??d??t??
?a?ep?st?µ??? ???a??? ?µ?µa ???. ????. ?p??.
S?st?µ?t??
2
?e??e??µe?a

• ?as??? ?a?a?t???st??? ???ef???a?
• ??????? t?? ???ef???a?
• ??ad??t?a?? ???ef???a
• ??????????t?ta ??ad??t?a?? ???ef???a
• ??e??e?t?µata-?e???e?t?µata-???ß??µata
• G??st?? ?p??es?e? ??ad??t?a??? ???ef???a?
• ???t?se??

3
???p?? ?e?t?????a? t??ef?????? s?st?µ?t??

• 1? ??µa???at?stas? S???d??
• o ?a??? s????e? t? t???f???
• ? ?a??? p??sd?????e? t? d?e????s? t?? ?a???µe???
  p.? 227380000
• ??a??t?s? t?? ?a???µe???
• o ?a???µe??? e?d?p??e?ta? ?t? ??e? ???s?
• 2? ??µa ?et?d?s? F????
• 3? ??µa ?e?µat?sµ?? S???d??

4
??????? t?? ???ef???a?

• 1870 ??a?????? t?? ???ef????
• 1877 ??µ??????a t?? p??t?? t??ef?????? G?aµµ??
• ?p? t? ??st??? st? ?asa???s?t?
• 1970 BroandBand Integrated Services Digital
  Network
• 1995 p??t? efa?µ??? µet?d?s?? f???? µ?s?
  ??ad??t???
• 2000 ?a???? ?p??es??? t??ef???a? µ?s?
  d?ad??t???

5
?a?e????
?a???
6
?et?d?s? f???? ??s? IP ???t??? (Voice over IP)

• ????p???s? d??t??? ?ed?µ????
• ???at?stas? S???d??
• ?et?d?s? F????
• ??a ta ded?µ??a µetad?d??ta? ??f?a??

7
??ad??t?a?? ???ef???a

• ?a???? ?p??es??? F???? µ?s? t?? ??ad??t???
• ??d??? pe??pt?s? t?? Voice over IP
• ????p?????ta? ?? ßas???? ?p?d?µ?? t?? d?ad??t???
• DNS
• WWW
• AAA

8
Ge???? ????te?t????? ??ad??t?a??? ???ef???a?
PSTN Phone
PSTN Phone
DNS ENUM AAA
PSTN C
VoIP Client
PSTN A
MG
IP Network Domain A
IP Network Domain B
PSTN B
MG
VoIP Server
VoIP Server
PSTN Phone
VoIP Client
VoIP Client
9
G?at? ??????????t?ta??

• ?pa?te?ta? µ???? ?a??st???s?
• 150ms
• ???at?t?ta µetaf???? "µe?????" ????? ded?µ????
• ?? apa?t?se?? t?? ???st?? de? a??????? se s??s?
  µe t?? ??ass??? t??ef???a

10
??????????t?ta ??ad??t?a?? ???ef???a
Codec Nominal Data rate datatagram Spacing Required Bandwidth
G.711u 64.0kbps 20ms 87.2kbps
G.711a 64.0kbps 20ms 87.2kbps
G.726-32 32.0kbps 20ms 55.2kbps
G729 8.0kbps 20ms 31.2kbps
G.723.1 MPMLQ 6.3kbps 30ms 21.9kbps
G.723.1 ACELP 5.3kbps 30ms 20.8kbps
11
??e??e?t?µata

• ?aµ??? ??st??
• ?a???? ?????µ???? ?p??es???
• Click to dial
• Voice mail
• Conference rooms
• Instant Messaging

12
?e???e?t?µata-p??ß??µata

• ????p?st?a
• ??a?es?µ?t?ta
• ?sf??e?a

13
?p??es?e? ??ad??t?a??? t??ef???a?

• ??e??e?? ???????
• Skype
• Gizmo
• VoIPBuster
• ??????? st?? e??????? ????
• i-call
• InterConnect
• iptel.gr
• webcall

14
??ass??? ???ef???a vs ??ad??t?a???
??????sµ?? OTE skype Gizmo VoIPBuster I-call Iptel.gr webcal
????da 0.03094 0.020 0.0141 0.012 0.0179 0.020 0.0137
????da-??? 0.1662 0.215 0.2614 0.202 0.1559 0.185 0.1413
Ge?µa??a 0,2493 0.215 0.141 0.012 0.0179 0.020 0.102
Ge?µa??a ??? 0.3372 0.200 0.1797 0.23 ?? 0.467 0.1575
?µe???? 0.29334 0.020 0.0141 ??? 0.0179 0.020 0.010
?µe???? ??? ??? ?? 0.0141 0.012 ?? 0.020 ???
15
??ass??? ???ef???a vs ??ad??t?a???
16
S?µpe??sµata

• ? d?ad??t?a?? t??ef???a ap?te?e? ?s?? t?
  s?µa?t???te?? te????????? e?????? st?? t?µ?a t??
  t??ef???a?
• ????e?ta? ??s?ast??? ??a µ?a d?af??et???
  p??s????s? st?? t?µ?a t?? µet?d?s?? f????
• ???sf??e? e?a??a?t??? ??s? st??? ?ata?a??t??
  µe?????ta? t? ??st?? t?? ???se?? p??
  p?a?µat?p?????
• ?????e? t? ep????????a?? t?p?? st? ep??e???µat???
  pe??ß?????

17
???t?se??