??????????S: ???S????S ???SS??S

1
??T??????????O???S ???????O? ??? ???????G??S
INTERNET I
????T ??G???S??S ???GG????????S ????????S?S ???
???????S?S ??? ???????S ?????????????????S
???????G??S INTERNET ????????

• ??????????S ???S????S ???SS??S
• ????? ??S?????

2
??de??t??? ?ata??µ? ????
3
?ef. 1 (T) ?ef. 9 (?) ???t??? ep????????a?
ded?µ????
4
???t??? ep????????a? ded?µ????
5
???t??? ep????????a? ded?µ????

• ???? ??t? ? s?s?e?? pa???e? ta ded?µ??a.
• ??µp?? ? p?µp?? µeta???se? ?a? ??d???p??e? t??
  p????f???a µe t?t??? t??p?, ?ste ?a pa???e?
  ??e?t??µa???t??? s?µata ta ?p??a µp????? ?a
  µetad????? µ?s? ??p???? e?d??? s?st?µat??
  µet?d?s??.
• S?st?µa µet?d?s?? ??t? µp??e? ?a e??a? µ?a µ???
  ??aµµ?µet?d?s?? ? ??a p???p???? d??t?? p??
  s??d?e? t?? p??? µe t?? p?????sµ?.
• ???t?? ? d??t?? d??eta? t? s?µa ap? t? s?st?µa
  µet?d?s?? ?a? t? µetat??pe? se t?t??a µ??f? ?ste
  ?a µp??e? ?a e??a? ?ata???t? ap? t?? s?s?e??
  p?????sµ??.
• ??????sµ?? ?a???e? ta e?se???µe?a ded?µ??a ap?
  t?? d??t?.

6
?e?????? a?a??????? ?a? ??f?a??? µet?d?s??
7
? d?ad??as?a t?? d?aµ??f?s??

• ??????FOS? ? µetaß???, s?µf??a µe t??
  p????f???a, µ?a? ? pe??ss?t???? pa?aµ?t??? e???
  f????t?? ??µat?? (carrier wave) p?? e??a?
  ?at?????? ??a t?? µet?d?s? µ?sa ap? t? ded?µ???
  ?a????.
• ?????????FOS? e??a? ? a?t?st??f? d?ad??as?a
• ?? e?d?? t?? d?aµ??f?s?? ?a?????e?
• ??? a?t??? st? ????ß? ?a? t?? pa?aµ??f?s?
• ??? p?st?t?ta a?apa?a????? t?? a?????? s?µat??
• ?? e???? t?? apa?t??µe??? ??a t?? µet?d?s?
  f?sµat??
• ??? p???p????t?ta t?? s?st?µ?t?? e?p?µp?? ?a?
  ?????

7
8
?? ep?t???????µe µe t?? d?aµ??f?s?

• ??? µet?d?s? p????? s?µ?t?? st?? ?d?? ???? µe
  ???s? d?af??et???? fe???t??
• ??? e??tt?s? t?? apa?t?se?? sta ?a?a?t???st???
  t?? s?st?µ?t?? e?p?µp??
• ??? ???s?µ?p???s? pe?????? t?? f?sµat?? µe
  ?a??te?e? s?????e? µet?d?s??

8
9
?? d?epaf?? se ??a µ??t??? ep????????a? (1/3)

• DTE (Data Terminal Equipment) ?p??ad?p?te
  ?e?µat??? S?s?e??
• DCE (Data Circuit-Terminating Equipment)
  ?a??d?a Modems

10
???t?pa ?a??d??se?? DCE (2/3)

• EIA-232 Interface (p???? RS-232) µe 25 a???d??te?
  a?se????? ? ??????? t?p??. ?µß??e?a 15 m,
  ?a??t?ta 20 kbps
• ???-449
• DB-37 (37 a???d??te?)
• DB-9 (9 a???d??te?)
• RS-422, RS-423, EIA-530
• X.21 ?p??e? ?a p?e? µ???? 64kbps

11
MODEM DCE (3/3)

• To MODEM (??aµ??f?t??-?p?d?aµ??f?t??)
  ???s?µ?p??e?ta? st?? ??f?a?? ep????????a µ?s?
  a?a??????? ??aµµ??.
• ?etat??pe? ??a ??f?a?? s?µa se a?a?????? (D/A)
  ???s?µ?p????ta? t?? te?????? d?aµ??f?s??
• ASK
• FSK
• PSK
• QAM
• ?a? a?t?st??f?? ap? a?a?????? se ??f?a?? (A/D)

12
?as???? t?p?? ??f?a??? d?aµ??f?s??
ASK FSK PSK
12
13
???f?? µet?d?s??

• ?a??????? ep????????a (8 bits) st?????ta?
  ta?t?????a, ??a ??e?????ta? 8 a?e???t?te? ??aµµ??
  s??des??.
• Se???a?? ep????????a (1 bit) ?a? ??e???eta? µ???
  1 ??aµµ? s??des??.
• S??????? µet?d?s?
• ?s??????? µet?d?s?

14
?a???s?as? st? e??ast????

• ??as??des? RS-232 (pa???s?as? D-connector,
  a???????a s?µ?t?? se e?p?µp? data ap? DTE,
  a???????a s?µ?t?? se ???? data ap? DCE,
  t??p?p???s? ?a??d??? ??a s??des? DCE-DCE ?a?
  DTE-DTE)
• modems AT e?t???? (s??des? e??te????? modem
  st?? ?/?, e??at?stas?, ???sµ?? pa?aµ?t???,
  ep?ßeßa??s? ep?t????? e??at?stas??, ßas???? ??
  e?t????, ?pt???? e?de??e?? s?s?e??? modem)
• ??????µµata ep????????a? ?p?????st?? (p.?.
  Hyperterminal) ?a? ßas???? ?e?t?????e?
  (p??s?µ???s? te?µat???? ??a p??sßas? se
  ?e?t?????? ?/? ? se s?s?e??? t??ep??????????,
  ???µ?s? pa?aµ?t??? ep????????a?, µetaf???
  a??e???)
• ???t?????a ep????????a? ( pa???s?as? t?? d?µ??
  ?a? t?? ?e?t??????? ap??? p??t???????, ?p?? p.?
  Xmodem, ?modem ?a? ???s? t??? ??a µetaf???
  a??e???)
• S??des? d?? ap?µa???sµ???? ?/? µ?s? t??ef??????
  ??aµµ?? (ßas???? ?? e?t????- ?p????????a µe
  modem, ???s? se ?/?, pa?aµet??p???s? t??
  Hyperterminal, µetaf??? a??e???)
• S??des? d?? ?/? t?? e??ast????? se???a??,
  pa??????a, as??µata, µ?s? TCP/IP.

15
? d?as??des? RS-232

• H d?as??des? (p??ta) RS-232 (Recommended Standard
  232) ???s?µ?p??e?ta? ??a t? se???a?? µet?d?s?
  ded?µ???? µeta?? e??? DTE ?a? e??? DCE µ?s?
  p????aµµ?t?? ?p?? t?
• MATLAB
• Microsoft Hyperterminal
• ?? D-connectors

16
?a s?µata st?? p??sa?µ???a (adapter) DB 9

1. Data carrier detect
2. Receive data (Rx)
3. Transmit data (Tx)
4. Data terminal ready(DTR)
5. Signal ground
6. Data set ready (DSR)
7. Request to send(RTS)
8. Clear to send(CTS)
9. Ring indicator

• ???t?s? ???a pins ?a p??pe? ?a ß?a???????????
  µeta?? t??? st? µ?a ?a? t?? ???? p?e??? t??
  p??sa?µ???a ??a ?a ?p???e? ep????????a

17
?? UART

• ?ept?µ??e?e? t?? d?aµ??f?s?? ?a?a?t???? ?a? t??
  ???µ?? µet?d?s?? e??????ta? ap? t? ????? t??
  se???a??? ???a?, p?? e??a? ??a ????????µ???
  ?????µa, t? UART (universal asynchronous
  receiver/transmitter), t? ?p??? µetat??pe?
  ded?µ??a ap? pa??????? se se???a?? µ??f?.

18
?odems (1/4)

• S??des? e??te????? modem st?? ?/?
• ???at?stas?,
• ???sµ?? pa?aµ?t???,
• ?p?ßeßa??s? ep?t????? e??at?stas??,
• ?as???? ?? e?t????,
• ?pt???? e?de??e?? s?s?e??? modem)

19
Modems (2/4)

• ?a ????? Modems pe????????ta? ap? t? e???? ?????
  t?? t??ef?????? ??aµµ??.
• ?? t??ef?????? ??aµµ?? ????? e???? ????? pe??p??
  4000 Hz.
• H de??µat?????a ???eta? µe ???µ? 8.000
  de??µata/sec ?a? ? d?aµ??f?s? (PCM) ???s?µ?p?e? 7
  bits/de??µa.
• ?ts? te???? ????µe ta??t?te?
• 8.000 de??µata/s X 7 bits/de??µa 56 kbps

20
Modems (3/4)

• ?e?a??te?e? ta??t?te? d????? ta cable modems p??
  pa?????? ?a? t?? ?a??d?a?? t??e??as?.
• ?a ?µ?a?????? a?t? ?a??d?a d????? 750 MHz e????
  ?????, e?? d?at??e?ta? ?a????a t?? 6 MHz. ?e????
  p????pt??? ?? ?e???t??? µ???ste? t?µ??
• Downloading 6 MHz X 6 36 Mbps µe ap?d?aµ??f?s?
  64-QAM (6 bits t? f???).
• St? p???? 3 10 ?bps.
• Uploading 6 MHz X 2 12 Mbps µe d?aµ??f?s? QPSK
  (2 bits t? f???).
• St? p???? 0,5 - 1 Mbps.

21
?????s? t?? ?e?t?????a? t?? MODEMS (4/4)

• ?et?ßas? st?? efa?µ??? Networks µ?s? t??
  s??t?µe?s?? st?? ep?f??e?a e??as?a?
• ?p????? ?p????????a ded?µ???? (MODEM)
• ?????µa t?? S??des??
• ?????µa t?? browser
• ?p????? µ?a? ap? ta pa?e??µe?a URL
• ?a?a???????s? t?? ??µat?µ??f?? ap? t? µe???
  ?a??????.
• ???p?p???s? t?? T???ß??

22
Telnet ??????µµata ep????????a? ?p?????st?? (1/4)

• ?as???? ?e?t?????e? t?? Hyperterminal
• ???s?µ???s? te?µat???? ??a p??sßas? se ?e?t??????
  ?/? ? se s?s?e??? t??ep?????????? (p?. se routers
  CISCO).
• ???µ?s? pa?aµ?t??? ep????????a?.
• ?etaf??? a??e???.
• ?as???? ?? e?t????.
• ???s? ?a? s??des? d?? ?/? µ?s? t??ef??????
  ??aµµ??.

23
?? Microsoft HyperTerminal (2/4)

• G?a t?? p??sßas? st?? efa?µ??? HyperTerminal sta
  Windows XP a????????µe t? µ???p?t?
• Start Menu ?Programs ?Accessories?
  ?Communications ? HyperTerminal

24
???µ?s? t?? HyperTerminal (3/4)
25
???µ?s? t?? HyperTerminal (4/4)
26
???t?????a ep????????a?

• ?? ?e?t?????e? t??? s?et????ta? µe t?? ?a????sµ?
  t?? µe?????? ?a? t?? ??e??? ??a t? s?st? t???
  ???? ?p?? t? checksum p?? ap?te?e? t? ?????sµa
  ???? t?? bytes t?? pa??t?? modulo 256.
• ?? modulo ?p??????eta? ap? ta 8 least
  significant bits (p?? ?µ?? µetad?d??ta? p??ta!).
  ?? ta pa??ta e??a? 2 ap? 130 bytes, t? s?????
  e??a? 260 ?a? t? checksum e??a? 4)
• XMODEM, sta 1990 (µ??e??? pa??t?? 128-byte, ?s?
  t? pe??e??µe?? µ?a? d?s??ta? d??ad?)
• ?MODEM µ?a ?e?te?? ??d?s? p??t??????? ?????
  µe???? ap???s?
• ?MODEM ?e??e?ta? p???? t? p?? d?aded?µ???
  p??t??????.

27
S??des? d?? ?/? t?? e??ast?????

• se???a??,
• pa??????a,
• as??µata,
• µ?s? t?? TCP/IP

28
Se???a?? ?a? pa??????? ape??e?a? s??des? ?/? (1/2)
29
Se???a?? ?a? pa??????? ape??e?a? s??des? ?/? (2/2)
30
?s??µat? s??des? (1/2)
31
?s??µat? s??des? (2/2)
32
S??des? µ?s? ?CP/IP (1/3)
33
S??des? µ?s? ?CP/IP (2/3)
34
S??des? µ?s? ?CP/IP (3/3)
35
?ef. 2St???e?a µet?d?s?? (T)
36
??d??e? ep????????a? (1/6)

• ? ?????f???a a?apa??stata? ap? ???µµata t??
  a?faß?t??, a???µ???, s?µe?a st???? ?a? ??????
  ?a?a?t??e?-s?µß??a
• ?? ??e?t??????? ?p?????st?? µp????? ?a?
  ?e??????ta? µ??? ta d?ad??? ??f?a 0 ?a? 1 (bit).
• G?a ?a ?p???e? ep????????a µeta?? a????p?? ?a?
  ?p?????st?? p??pe? ?a µetat?ap??? ?? ?a?a?t??e?
  se se???? ap? bit.
• G?a t?? µetat??p? a?t? ???s?µ?p?????ta?
  s???e???µ???? p??a?e? a?t?st????a? ? p??a?e?
  ??d???p???s?? ? ??d???se??de? ? ??d??e?.

37
??d??e? a?apa??stas?? (2/6)

• ?? ??d??e? s?????? pe???aµß????? ta pa?a??t?
  s?µß??a
• 10 a???µ?t??? ??f?a 0 ??? ?a? 9
• 26 ?at????? ?efa?a?a ???µµata
• 26 ?at????? µ???? ???µµata
• S?µß??a ?a? s?µe?a st???? .?,?-/()\_at_ ??p
• ?a?a?t??e? e?????? STX, EOT, SYN, ACK ??p
• ???????? ???µµata !!

38
??d??a? ASCII (3/6)

• ? ASCII (American Standard Code for Information
  Interchange)? e??a? ? p?? d?aded?µ???? ??d??a?
  a?apa??stas?? ?a?a?t????.
• ?????? ? ??d???p???s? ASCII ??a??p????se t??
  a????e? t?? p????aµµ?t?? p?? apa?t??sa? ??a
  pe?????sµ??? s????? ??d???p???µ???? ?a?a?t????.
• ? e?????? ?µ?? t?? ?p?????st?? d?µ??????se t??
  a????? ???? µ??f?? ??d???p???s?? t?? ?e?µ????
  ?p?? e??a? ?? ISO ?a? Unicode ?a??? ?a? ??e?
  ???sse? pe????af?? ?p?? ? ??d???p???s?
  ?st?se??da? HTML.

39
??a pa??de??µa ASCII ??d???p???s?? (7bit) t??
????? HELLO (4/6)
40
??d???se??de? ISO (International Standards
Organisation)? (5/6)

• S?µa?t??? µe?????t?µa t?? ASCII e??a? ?t?
  pe???aµß??e? µ??? ?at??????? ?a?a?t??e?.
• G?a t? ???? a?t? d?µ?????????a? epe?t?se?? t??
  (???s? 8 bit), ?? ?p???? µp????sa? ?a
  a?t?st????s??? a??µa ?????? 28 256 ?a?a?t??e?.
• ?? p??te? 128 ??se?? e??a? ?d?e? µe t?? ASCII ?a?
  ?? ep?p???? 128 ?a?a?t??e? e??a? ??a e?d???
  s?µß??a ????? a?f?ß?t??
• G??st?? ??d??e? p?? ???s?µ?p?????ta? st?? ????da
• IBM 851, IBM 869, 737 ? a????? e???????? 437
  (??at? p??????e ap? t?? aµe???????? ??d???se??da
  437)
• ???? 928 e??a? ? p?? s??????? t?p?p???s? ?a?
  ?a??e?????e a????? ap? t?? ???? ?a? a???te?a
  ????e ap?de?t? ap? t?? ISO-Latin-8859-7 ? ap??
  Latin 7.

41
Unicode ??d???p???s? (6/6)

• ? a??pt??? ??d???se??d?? ISO ???se µe????? t?
  p??ß??µa µe ta d??f??a a?f?ß?ta.
• ? ????pa??? ???s? ??e?a??ta? p??????
  ??d???se??d?? ??a ?a ?a???e? ??e? t?? ???e? µ???
  t?? ?a? ?ts? d?µ?????????e ? ??d???se??da
  Unicode, p?? p??te??e? ??a ???e ?a?a?t??a, ??a
  µ??ad??? a???µ? a?e???t?ta ap? t? ?e?t???????
  s?st?µa, t? ????sµ??? ?a? t? ???ssa.
• ???e ??d???p???µ??? ???? Unicode ??e? µ???? 16
  bit d??ad? ep?t???????ta? 21665536 s??d?asµ??
• ? Unicode pa???e? ??d???p???s? ??a t???
  ?a?a?t??e? ???? t?? ???ss?? s?µpe???aµßa??µ????
  t?? ????pa????, t?? ??s?? ??at???? ?a? t?? ?s?a?.

42
???f?? µet?d?s?? (1/5)

• ?a??????? ep????????a (8 bits) st?????ta?
  ta?t?????a, ??a ??e?????ta? 8 a?e???t?te? ??aµµ??
  
• Se???a?? ep????????a (1 bit) ?a? ??e???eta? 1
  ??aµµ? s??des??.
• S??????? µet?d?s?
• ?s??????? µet?d?s?

43
Se???a?? µet?d?s? (2/5)
44
?a??????? µet?d?s? (3/5)
45
S??????? µet?d?s? (4/5)

• ?et?d?s? µ?a? p????f???a? teµa??sµ??? se pa??ta
• ?pa?a?t?t? p???p??es? ??a t? µet?d?s? t??
  ded?µ???? e??a? ? s???????sµ?? µeta?? p?µp?? ?a?
  d??t?.
• St???? e??a? ? ???µ?? de??µat?????a? t?? d??t? ?a
  ta?t??eta? µe t?? ???µ? µet?d?s?? t?? bit.
• ?????µata ?????sµ?? ?a???????? t?? ???µ?
  µet?d?s??.
• ? d??t?? p??pe? ?a ???t??e? st?? µ?s? t??
  d????e?a? t?? bit ??a ?a p??sd?????e? t?? t?µ?
  t?? ap?ste???µe??? bit (0 ? 1).
• ?e???a pa??ta de? µp????? ?a µetad????? se
  as??????? ?e???.

46
?s??????? µet?d?s? (5/5)

• ? ap?st??? t?? ded?µ???? ???eta? ?p? µ??f?
  ?a?a?t????, ?? ?p???? µetad?d??ta? ??a?-??a?, µe
  ??p??? ?e?? ??????? d??st?µa µeta?? t??? ??a ?a
  d?a??????? ap? t? d??t?.

47
?ate????s? ?et?d?s?? ?ed?µ???? (1/3)

• ? ?ate????s? t?? µet?d?s?? t?? ded?µ???? µp??e?
  ?a e??a?
• ?p?? ? µ???d??µ? (Simplex)
• ?µ?aµf?d??µ? (Half-Duplex) a? µp??e? ?a ???e?
  µet?d?s? ?a? p??? t?? d?? ?ate????se?? a?? ???
  t?? ?d?a st??µ?.
• ?µf?d??µ? (Full-Duplex) a? µp??e? ?a ???e?
  µet?d?s? ?a? p??? t?? d?? ?ate????se?? ???e
  st??µ?.

48
????d??µ? (2/3)

• St? µ???d??µ? µetaf??? ta ded?µ??a ????? t?? ?d?a
  f??? st? ?a???? µet?d?s??
• ?a??de??µa - S??des? ?/? µe ??t?p?t?

49
?µf?d??µ? ??a??ass?µe?? (3/3)

• ?a ded?µ??a ??????ta? ?a? p??? t?? d??
  ?ate????se?? a??? ??? ta?t?????a (?µ?aµf?d??µ?).
• ?a??de??µa Walkie Talkie

50
?et?d?s? s?µe??? p??? s?µe??

• ?? ??µß?? (? te?µat???) e??a? s??deµ????
  ape??e?a? µeta?? t???.

51
?et?d?s? e?p?µp??

• ??a? ??µß?? a?a?aµß??e? t? ???? t?? p?µp??, e??
  ??p???? ????? ??µß?? ?aµß????? ta ded?µ??a ??
  d??te?.
• S?efte?te t? ?p?? t?? t??e??as? ? sta?µ??
  e?p?µpe?, a??? de? ??????e? a?? p?sa st??µ? p?se?
  t??e???se?? t?? ?aµß?????.

52
???µ?? ?et?d?s??

• ?et???ta? se bits (d?ad??? ??f?a) a??
  de?te???ept? ?a? ??? se bytes
• H µ???da e??a? t? bps (bits per second) ?a? ta
  p???ap??s?a t??
• ?a??t?ta µet?d?s?? 1?bps s?µa??e? 1.000.000 bits
  t? de?te???ept?.
• ?pe?d? 1 byte8bits 1 Mbps 1.000.000/8125.000
  bytes t? de?te???ept?

53
???µ?? Sfa?µ?t?? ??ad???? ??f???

• ?? ste????µe 1.000.000 d?ad??? ??f??, ?a? ta 3
  ??f???? ?????, ????µe ???µ? sf??µat?? 3/1.000.000
• Se as??µata d??t?a ? ???µ?? sfa?µ?t?? e??a?
  s?????? p?? µe????? ap? ta e?s??µata.

54
?????e?s? ?a???

• ????d?? a????e?s??
• Parity (?s?t?µ?a)
• pe??tt?
• ??t?a
• Checksum
• ?p??????eta? a? p??ste?e? ? de?ad???? ASCII
  a???µ?? ???e ?a?a?t??a t?? µ???µat?? ?a?
  d?a??e?e? t? ?????sµa µe t? 255. ?? ?p????p? t??
  d?a??es?? ap?te?e? t? checksum.
• ?? checksum (?p????p?) µetad?deta? µe t? µ???µa.

55
?ef. 3??sa µet?d?s?? (T)
56
??sa ?et?d?s?? ?ed?µ????

• ??s??µata
• ?a??d?a S??est?aµµ???? ?e????? (Twisted Pair)
• Shield Twisted Pair.
• Unshielded Twisted Pair.
• ?µ?a?????? ?a??d?a
• ?as???? ????? (Baseband Coaxial Cable) thinnet.
• ???e?a? ????? (Broadband Coaxial Cable) -
  thicknet.
• ?pt???? ??e?
• ????t??pe? (single mode).
• ????t??pe? (multi-mode).
• ?s??µata
• ???a?
• ?ad????µata - Radio
• ???????µata -Microwave
• ?p?????e? Infrared.

57
???t???a ep?????? µ?s?? µet?d?s?? ?a? st???e???
d?as??des??

• ?p?st?se?? - ????? ?a??d???
• ?pe?tas?µ?t?ta - ??aßa?µ?se??
• ??t??? st?? ß??ße? - ??a?es?µ?t?ta
• ?e??ß????? - ?a?eµß????
• ??????a e??at?stas??.

58
T??a??sµ??a /???????sta S??est?aµµ??a ?a??d?a
(1/4)

• ?a UTP ap?te????
• ??????µ??? ep????? ??a d??t??s? LAN
• ????? e??e?a d??d?s? sta s?µe???? LAN
• ???s?µ?p????? 1 ?e???? ?a??d???.
• ?a STP ???s?µ?p?????ta? ?p?? ?p?????? p??ß??µata
  pa?eµß????.

59
?? s?µa sta s??est?aµµ??a ?a??d?a (2/4)
LINE 1
LINE 2 -

• ??t?st??f? t?? f?se??, ?ste ?a apa?e?f?e? ?
  ????ß??.

60
?at?????e? ?a??d??? (3/4)

• S?????? a?afe??µaste sta ?a??d?a ?at?????a? 3 ?a?
  5
• ? ?at?????a 5 ??e? a?t??atasta?e? ap? t?? CAT 5E
  µe 4 ?e??? s??est?aµµ??a a?? 2.
• ? ?at?????a 6 d?p?as???e? t? e???? ????? t??
  ?at?????a? CAT 5.
• ? ?at?????a 7 ft??e? ta 600 Mbps.

61
S??desµ?????a s??est?aµµ???? (4/4)

• ?e??? ?a??d???
• blue, white-blue
• orange, white-orange
• green, white-green
• brown, white-brown
• ?at?????e? ß?sµ?t?? RJ-11 ?a? RJ-45.
• ?a Cross over ?a??d?a ???s?µ?p?????ta? ??a t??
  ape??e?a? s??des? d?? ?/?, s??d???ta? t? p??s???
  t?? µ?a? ????? µe t? p??t??a?? t?? ????? (?e????
  µet?d?s?? µe ?e???? ?????).
• D connectors.

62
RJ-45 (Jack 45) ???s?µ?p?????ta? 8 ?a??d?a ??a
Ethernet d??t?a.
63
RJ-11 4 ? 6 ?a??d?a ??a ta t???f??a
64
?µ?a?????? ?a??d?a

• ?p?te????ta? ap? d?? a??????.
• ????te?? e?a?s??ta st?? pa?eµß??? ?a? t??
  s??a???as? ap? ?t? ??a s??est?aµµ??? ?e????.
• X??s?µ?p?????ta? ??a µe?a??te?e? ap?st?se??.
• ?a?????? µe?a??te?? e???? ????? se s??s? µe ta
  s??est?aµµ??a ?e???.
• ?µ?a?????? ?as???? ????? (thinnet, ?ept?)
• ?a???? ???µat??
• 185 µ?t?a ap?stas?.
• ?µ?a?????? ???e?a? ????? (thicknet, ???t??).
• ??t????? ???µat??.
• 500 µ?t?a ap?stas?.

65
?pt???? ??e? (1/4)

• ???s?µ?p?????ta?
• G?a ?a ?a?????? µe?a??te?e? ap?st?se??.
• ?ta? apa?t???ta? µe???e? ta??t?te?.
• ?ta? ?p?????? p??ß??µata µe????? pa?eµß????.
• ?ta? apa?te?ta? asf??e?a st? µet?d?s?.
• ???? p?? d?s???? ? ???p???s? t??? ap? ta UTP
  ?a??d?a.

66
?pt???? ??e? (2/4)
Laser
Single Mode ????t??pe?
8/125 micron
????? 50 µ???a
LED
Multimode ????t??pe?
62.5/125 micron
????? 2000 µ?t?a
67
?pt???? ??e? (3/4)

• St?? p???t??pe? ?pt???? ??e?, ? p????a? t??
  ?pt???? ??a? ??e? s?et??? µe???? µ??e??? µe
  ap?t??esµa t? f?? ?a ?????f??e? µ?sa st?? ?pt???
  ??a? ??? µe t?? µ??f? µ?a? ?a? µ??ad???? a?t??a?,
  a??? p?????.
• St?? µ???t??pe? ?pt???? ??e? t? f?? ?????f??e? µe
  t?? µ??f? µ?a? ?a? µ??? a?t??a?. ???a?
  ?ept?te?e?, p?? s???ete? st?? ?atas?e?? ?a?
  µp????? ?a ???s?µ?p??????? ??a µe?a??te?e?
  ap?st?se??.

68
??sµata ?pt???? ???? (4/4)
69
?s??µata f?s??? µ?sa (1/2)

• F?s??? µ?s? e??a? ? a??a? (atµ?sfa??a) ? a??µa
  ?a? t? ?e??.
• ??asp??? ??e?t??µa???t???? f?sµat?? s????t?t??
  (Spread Spectrum)
• ?ad????µata
• ???????µata
• ?p?????e?
• LASER
• ?a ?ad????µata s?et??? ?aµ???? s????t?t?? µp?????
  ?a ?epe??s??? ad?afa?? eµp?d?a.
• ?a ?ad????µata ?????? s????t?t?? (?a?
  µ??????µata) d?ad?d??ta? e?????aµµa ?a?
  ??e?????ta? ??s?ast??? ?pt??? epaf?.
• ?? ?p?????e? a?t??e? ?a? t? f?? ?e????
  ??e?????ta? ?pt??? epaf?.

70
?? ??e?t??µa???t??? f?sµa (2/2)
71
?? e??a? s?µa ?as???? ?????

• ?p?st??? (µe p??? ?aµ???? s????t?te?) t??
  p????f???a? 1 0 0 1 1 0
• ?? ?????? 1 e??a? ? ?et??? t?µ?
• ?? ?????? 0 ? a???t??? t?µ? (?a? ??? t? 0)
• ?? ???e bit ap?st???eta? se pe???d???
  (?????????de?) ?se? µeta?? t???.

72
?? e??a? s?µa e??e?a? ?????
73
T???ß?? pa?aµ??f?s? (1/8)

• ???a? ? ????? p?? de? ???s?µ?p????µe µet?d?s?
  ßas???? ????? st?? as??µate? ep????????e? (a???
  ?a? ??a µa?????? ap?st?se?? st?? e?s??µate?).

74
T???ß?? pa?aµ??f?s? (2/8)

• ?? d??µe ??a pa??de??µa.
• St?????µe t? s?µa 1101001000

75
T???ß?? pa?aµ??f?s? (3/8)

• ??? ?e???te ?t? t? s?µa p??pe? ?a d?aµ??f??e?.
• ??p?? ?ts? ???a? t? ?da???? d?aµ??f?µ??? s?µa µe
  ASK (Amplitude Shift Keying) d??ad? d?aµ??f?s?
  p??t???.

76
T???ß?? pa?aµ??f?s? (4/8)
...?µ??, ???? ????ß?? ?aµß????µe
77
T???ß?? pa?aµ??f?s? (5/8)

• S????????ta? ta s?µata...

?da????
??a?µat???
78
T???ß?? pa?aµ??f?s? (6/8)
?? d??µe µa?? t?? a????? p????f???a ?a? a?t? p??
te???? ?a ??ß??µe
???a? te???? s?st?
79
T???ß?? pa?aµ??f?s? (7/8)

• ??? ?a p??? t?? a????? p????f???a
• ?? ?p?????s? t?? µ?s? ??? t?? p??t??? t?? s?µat??
  ??a ???e pe???d? bit, t? ?a ß??
• ?? ß?? ?et??? a???µ?, t?te ??? 1
• ?? ß?? a???t??? a???µ?, ??? 0.

80
T???ß?? pa?aµ??f?s? (8/8)

• ??a?t???, ? a??????µ?? d???e?e? ?a??!
• ???a??t?ta ??????
• 8 bit ??a ???e 10.000 bit (810-4)
• ???et? ?a?? de ??µ??ete
• S?µp??asµa Sta ??f?a?? s?µata, de? ??e???eta?
  ?a a?apa?????µe t?? a????? ??µat?µ??f?, ?p?? sta
  a?a??????!

81
?e???d?? - S????t?ta

• ??a s?µa p?? epa?a?aµß??eta? ???µ??eta?
  pe???d???.
• ?e???d?? se ??a t?t??? s?µa e??a? ? ?????? p??
  ??e???eta? ??a µ?a p???? e?a??a?? (d??. ? ??????
  µ???? ?a a???se? ?a epa?a?aµß??eta?).
• ? pe???d?? µet???ta? sa? ?????? se de?te???epta
  ?a? ?p?d?a???se??.

82
?e???d?? - S????t?ta

• S????t?ta ???µ??eta? ? a???µ?? t?? pe???d??
  (epa?a???e??) t?? s?µat?? se ????? e???
  de?te????pt??.
• ????da s????t?ta? e??a? t? Hertz (Hz)

???? ap? ta d?? s?µata a??ste?? ??e? µe?a??te??
s????t?ta
?? de?te?? (d?p??s?a s????t?ta) St?? ?d?? ?????
??e? ???e? t?? d?p??? epa?a???e??.
83
?ef. 4 ?e?????? µet?d?s?? (T)
84
?e?????? µeta????? (1/8)

• ?e????? µeta????? ???µ??eta? ? t??p?? µe t??
  ?p??? ap??a??stata? ? ep????????a a??µesa se d??
  ??µß??? µe s??p? t?? a?ta??a?? ded?µ????.
• ?eta???? ?????µat??
• ?eta???? µ???µat??
• ?eta???? pa??t??
• a?t?d??aµ??
• ???t?? ?????µat??.

85
??apa??stas? t?? te?????? µeta????? (2/8)
86
?eta???? ?????µat?? (3/8)

• G?a ???e µet?d?s? ded?µ????, e??a??stata? ??a
  µ???µ? (f?s???) ?????µa ??a ?s? ??a apa?te?ta?
  p.?. ta d??t?a ISDN ?a??? ?a? t? ??as???
  t??ef????? d??t??.

87
?eta???? ?????µat?? (4/8)
G
?
?
?
?
?
???t?? ?eta?????
88

?eta???? µ???µat?? (5/8)

• ?e? ?p???e? ??p??? µ???µ? f?s??? ?????µa.
• ?? ??µß?? µetad?d??? t?? p????f???a µ?sa se ??a
  ?a? µ??? pa??t? t? ?p??? d??µ????e?ta? ?at?????a
  µ?sa ap? t?? d??f??e? d??t?a??? s?s?e??? p??
  ?p?????? st?? d?ad??µ? µ???? ?a ft?s??? t??
  p?????sµ? t???.
• ?a???s???e? s?µa?t??? µe???e?t?µata (p?. apa?te?
  ?? e?d??µes?? ??µß?? ?a ????? µe???? ap????e?t???
  ????).

89
?eta???? pa??t?? (6/8)

• ?p?te?e? pa?a??a?? t?? µeta????? µ???µat??.
• ? p????f???a teµa???eta? se pe??ss?te?a t?? e???
  pa??t?? µet?d?s??.
• ?µfa???eta? µe d?? pa?a??a??? st?? te?????
• ???s? a?t?d??aµ?? pa??t?? (datagram).??
  e?d??µes?? ??µß?? a?ta???s??? ?at?????a ta pa??ta
  p?? d??µ???????ta?, ?ste a?t? ?a ft?s??? st??
  p?????sµ? t??? ?st? ?a? ap? d?af??et?????
  d??µ???. ?e? ??e? a???p?st?a (p?. ???s? UTP
  p??t???????).
• ???s? ???t?? ?????µat?? (VC). ?p?te?e? µ?a
  p??d?a??aµµ??? ???t? d?ad??µ? p?? a????????? ta
  pa??ta µ?sa se ??a d??t?? ??a ?a ft?s??? st??
  p?????sµ? t???.
• ?a ???t? ?????µata d?a??????ta? µe t? se??? t???
  se
• ???s????? ???t? ?????µata ?a?
• ????µa ???t? ?????µata.

90
?eta???? ?a??t?? µe ???s? ??t?d??aµ?? ?a??t??
(7/8)
G
?
?
?
?
?
???t?? ?eta?????
91
?eta???? ?a??t?? µe ???s? ???t?? ?????µ?t?? (8/8)
G
?
?
?
?
?
???t?? ?eta?????
92
?ef. 5 ???t?a ep????????a? (T)
93
?? e??a? d??t??

• ???t?? e??a? µ?a ?µ?da ?p?????st?? s??dedeµ????
  µeta?? t??? e?s??µata ? as??µata, ? ?p??a
  ep?t??pe? se p?????? a????p??? ?a a?ta???ss???
  p????f???e? ?a? ?a µ???????ta? ta?t?????a
  e??p??sµ?.

94
?? s?µa??e? ? ???? ep????????a

• ?p????????a e??a?
• ? ap?st??? µ???µat?? ap? ??a s?µe?? e??? d??t???
  se ??a ???? s?µe?? ? d??t?? ?a?
• ? ep?ßeßa??s? t?? ????? ?ata???t?? ????? ap? t??
  e???s??d?t?µ??? pa?a??pt?.

95
?p?te??? ep????????a? se a??µ????e??? pe??ß?????

• G?a ?a ep????????s??? d?? ?p?????st???
  s?st?µata p??pe? ?a ?p???e? µeta?? t????
• ?????? d?as??des? ?a?
• F?s???.
• ??d???te?a ? f?s??? d?as??des? ???p??e?ta? ap?
• ?? f?s??? µ?s? µet?d?s?? (p?. ?a??d?? UTP,
  a??a?).
• ??? t?p?????a d??t???.
• ?? µ???d? p??sßas?? st? µ?s?
• ??? te????? ?et?d?s?? ?a? ??d???p???s?? t??
  ded?µ????
• ??? ta??t?ta µet?d?s??.
• ?? d??t?a?? e??p??sµ?.

96
??d? d??t???

• ??p??? ???t?? (Local Area Network - LAN). S??d?e?
  ?p?????st?? se ??a pe?????sµ??? ????, ?p?? ??a
  ?t????.
• ??t??p???t??? ???t?? (Metropolitan Area Network -
  ???). S??d?e? ?/? p?? ß??s???ta? µ?sa se µ?a
  e??e?a pe????? ?p?? µ?a p???, ??µ?? ??p
• ???t?? ???e?a? ?e?????? (Wide Area Network -
  WAN). S??d?e? ?p?????st?? µ?sa se ??a µe????
  ?e???af??? ???? (???t??, ?pe????, p?a??t??).

97
?? ?a?e?????? ???t?? ??a t?? ??pa?de?s? (EDUnet)

98
????S?? ????FO???? ?????? (PSTN) (1/5)
S??d??µ?t??
?T??? ?st??? ???t??
?d??t??? ???ef????? ???t??
???t?? ??aß?ßast???? ???t???
????? ?st??? ???t??
T?S/?? CO
T?S/?? ?st??? ???t??
S??d??µ?t??
99
???t?? PSTN (2/5)

• ???sf??e?
• Sta?e?? t??ef???a
• ?s??µat? t??ef???a
• fax (µe e?s?µat?µ??? modem)
• ?p????????a ded?µ???? (data communication) µe
  modem

100
???t?? PSTN ?as??? ?a?a?t???st??? (3/5)

• ??a?????? p??sßas?, 300-3.400 Hz
• ???t?? µeta????? ?????µat?? µe aµf?d??µ?
  ep????????a (circuit-switched duplex connection)
• ????? ????? 3.100 Hz ??a a?a?????? t??ef?????
  ???t?a (telephone exchanges)

101
??f??p???s? t?? d??t??? PSTN (4/5)

• ???? ap? a?a?????? µet?d?s?.
• ?etat??p? a?a??????? ??aµµ?? se ??f?a??? ?e?
  ???a?a? ?? f?s???? ??aµµ??, a??? ? t??p??
  e?µet???e?s?? t?? ?a????.
• ?p?te??sµata e??at?stas?? ??f?a??? t??ef??????
  ???t???
• ?e??s? ????ß??.
• ?e?a??te?? p??sßas?.
• ??e? ?p??es?e? ?p?? ? a?a?????s?/ a?aµ??? /
  e?t??p? ???s??.
• ?e????µa ?????????s??.

102
???t?? PSTN T1 carrier ?a??d?a ?1 (5/5)

• ?o p??t? ??f?a?? µ???µ? ?????µa PSTN st??
  ?µe????.
• ? ???µ?? ded?µ???? e??a? 1,544 Mbps
• ?etaf??e? 24 ??f?a??? ???se?? ta?t??????? µ?s?
  ???????? ?a??d??? se ap?st?se?? µ???? 50 µ?????
• ???a ???s?µ?p?????ta? ?a? ?pt???? ??e?.
• ???s?µ?p??e?ta? ??a µet?d?s? f???? ?a? ??a
  µet?d?s? ded?µ????.
• ? µet?d?s? p????f????? µe t? T1 ???eta? DS1
  Digital Services 1.
• St?? ????p? ?p???e? a?t?st???a ? f???a? ?1 (2048
  Mbps).

103
??s??µ??e? ??aµµ?? (leased lines)

• T??ef?????? ??aµµ?? p?? e?????????ta? ??a
  ap???e?st??? ???s?.
• S??d?se?? ?????? ??a ep??e???µat??? ???s?.
• ?a?????? 24 ??e? µ???µ? p??sßas? µe ?a????sµ???
  ??st??.

104
???t??? Dial-up d?as??des?? (1/2)

• ?at? ?a???a ???s?µ?p??e?ta? ap? ????a????
  s??d??µ?t?? (1 ???st??)
• ???s? t?? ?p?????sa? t??ef?????? s??des??
• ????? ta??t?ta p??sßas??
• ?? sta?e?? s??des?
• S??d??µ? ?????????s? PSTN
• Over booking (15 1) t?? modems t?? ISP

105
???t??? Dial-up d?as??des?? (2/2)

• ?p?t??pe? t?? µet?d?s? bits µ?s? ??????
  t??ef?????? ??aµµ??.
• ???s?µ?p??e?ta? ?ta? ?? ?/? de? e??a? ???t?
• ? µet?d?s? ???eta? µ?s? t?? t??ef?????? ??aµµ??
  ?a? e??a? se???a??.
• ?? ??e? ??f?a??? t??ef?????? ??aµµ?? d????? t?
  d??at?t?ta ??a p??? ?????? ta??t?te? s??des??
  (ADSL).
• ?a pe??ss?te?a ????t? t???f??a p???? µp????? ?a
  ?e?t?????s??? ?? modem.

106
??f?a?? ???t?? ???p???µ???? ?p??es??? ISDN (1/2)

• ????te?t????? ???a??µ??? se ep?peda.
• St????eta? st?? ?p?????sa ?p?d?µ? t?? t??ef??????
  d??t???.
• ?p?te?e? e?e???µ??? d??t?? µeta????? ?????µat??.
• ?p??e? ?a µetaf??e? ???e ????? p????f???a (???,
  ß??te?, ded?µ??a ?p?????st??)
• ?????? ??f??p???s?
• ?a??te?? p???t?ta (??? ????ß??)
• Y????te?e? ta??t?te?
• ?????? d?af??et???? s?s?e??? p??? st?? ?d?a
  ??aµµ?.
• ?a??t?te? x64 Kbps.

107
??f?a?? ???t?? ???p???µ???? ?p??es??? ISDN (2/2)
???sßas? ???te???t?? ???µ?? (PRA)
???sßas? ?as???? ???µ?? (BRA)
30B D
2.048 Mbps

2B D

64 Kbps 64 Kbps 16 Kbps
64 Kbps 64 Kbps
144 Kbps

• ??a f?s??? s??des? µe t? ???t?? ISDN
• 30 ??????? s??d?se?? (?a????a) (E???p?)
• 23 ??????? s??d?se?? (U.S.? / Canada)
• ?e?µat???? ???p??sµ??

• ??a f?s??? s??des? µe t? ???t?? ISDN
• 2 ??????? s??d?se?? (?a????a)
• ?e?µat???? ???p??sµ?? (??1, ??2,
  ??, ??)

108
???t?a µeta????? pa??t?? ?? p??t?p? ?.25 (1/4)

• ?µfa??st??e st?? a???? t?? de?aet?a? t?? 1970
  e?a?t?a? t?? ???s?? t?? d?µ?s??? d??t???
  ep????????a?
• ?pa?t?s? ??a d?as??des? d?af??et???? s?st?µ?t??.
• ????? ??st?? t?? µ???µ?? s??d?se??.
• ?? p??t?p? ?.25 e??a? s?µßat? µe t? µ??t??? OSI
  ?a? ?a?????e? µ?a se??? ?a????? p?? ??????? t??
  ep????????a µeta?? t?? te?µat???? (DTE) ?a? t??
  ??µß?? µeta????? (DCE).
• ?? ßas???? ?p??es?e? p?? pa???e? t? ?.25 e??a?
• ??ta??a?? ??d???? ??a t?? ap??at?stas? µ?a?
  s??des??.
• ?e?t?????e? d?a?e???s?? d?ad??as?a? e??????
  sfa?µ?t?? ?a? e?asf???s?? a???p?st?? µet?d?s??
  p????f?????.

109
???t? ?????µata st? ?.25 (2/4)

• ?? d??t?? ?.25 ap?te?e?ta? ap? ??µß??? µeta?????
  pa??t?? ?? ?p???? s??d???ta? a?? d?? µe s??d?se??
  s?µe?? p??? s?µe??. G?a ?????? ??????µ?a? st??
  ?a??d??se??, e??a? d??at?? d?? te?µat??? ? DTE ?a
  µ???????ta? t?? ?d?a ??aµµ? ep????????a? µe t??
  ???st? µa? µ???d? t?? p???p?e??a? st? ????? (TDM).

110
? ?e?t?????a t?? ?.25 (3/4)

• ?a ded?µ??a st? ?.25 ???????ta? se pa??ta
  s???e???µ???? µe?????? p.?. 128 ?a?a?t???? e?t??
  ?s?? ap? t? te?e?ta??, t? ?p??? µp??e? ?a e??a?
  µ????te??.
• ?? ?.25 ?a?????e? t?? µ??f? t?? p?a?s??? t??
  pa??t?? ded?µ???? p?? ap?te?e?ta? ap?
• t?? ep??efa??da
• t? ped?? ded?µ???? t?? ???st? ?a?
• t? µetaß??t? ped?? p????f???a?
• ?a? e?s?µat??eta? st? p?a?s?? p????f???a?
  (information frame), t? ?p??? pe???aµß??e? ??e?
  t?? p????f???e? p?? apa?t???ta? ??a ?a ?a????ste?
  ? d?ad??µ? t?? pa??t?? ap? t? ??a s?µe?? st? ????.

111
? ep????????a st? p??t?p? ?.25 (4/4)

• ???p??e?ta? se t??a ep?peda
• F?s??? ep?ped? ??e???p???s? t?? f?s???? s??des??
  µ?a? DTE µe µ?a DCE.
• ?p?ped? ??aµµ?? ded?µ???? ? p????f???a
  ?µad?p??e?ta? se p?a?s?a. ?p?s?? ?a???????ta? ??
  d?ad??as?e? p?? apa?t???ta? ??a t?? a?ta??a?? t??
  p?a?s???.
• ?p?ped? d??t????a ded?µ??a pa?????? t? µ??f?
  pa??t?? ?a? µetaf????ta? ap? ?a? p??? t? d??t??.

112
?? p??t?p? µeta????? p?a?s??? (Frame Relay)

• ???s?µ?p??e?ta? sta d??t?a WAN
• ?p?te?e? ??s?ast??? e?????? t?? p??t?p?? ?.25
• ?e?t????e? sta d?? p??ta ep?peda t?? OSI (f?s???
  ?a? ??aµµ?? ded?µ????)
• St????eta? st? µeta???? pa??t?? ?a? µ???sta
  µetaß??t?? µ????? (variable length) ta ?p??a
  ???µ????ta? p?a?s?a
• ?????? ???s?µ?p??????e sta d??t?a ISDN a??? ap?
  t? 1988 ?a? µet? ??e? ße?t???e? s?µa?t??? ?a?
  ???s?µ?p??e?ta? e???te?a
• ???s?µ?p??e?ta? t?s? se d?µ?s?a ?s? ?a? se
  ?d??t??? d??t?a.
• ?p?t?????e? ???µ??? µet?d?s?? p?? e??a?
  p???ap??s?a t?? 64 Kbps (max 45 Mbps).

113
S?s?e??? d??t??? Frame Relay

• ?e?µat??? ?ed?µ???? (DTE)
• ?e?µat??? d??ta?? ?????µat?? (ep????????a?)
  ded?µ???? (DCE) ?a? ??
• S?s?e??? p??sßas?? µeta????? p?a?s??? FRAD (Frame
  Relay Access Device) p?? µp????? ?a d?a?e???st???
  p???? p??t?????a ?a? ???e? d??t?a??? s?s?e???.

114
?? p??t?p? ?eta????? p?as??? Frame Relay

• ???s?µ?p??e? ???t? ?????µata
• ?a???e? ep????????a d?p??? ?ate????s?? a??µesa se
  d?? DTE.
• ?e??ss?te?a ap? ??a ?a????a µp????? ?a
  µ???????ta? t? ?d?? f?s??? µ?s? ???s?µ?p????ta?
  t?? ???st? µa? µ???d? t?? p???p?e??a? TDM (st?
  ?????).
• ?a ?a????a ?a?a?t??????ta? ??a? a???µ? (µ?a
  ta?t?t?ta s??des?? ??aµµ?? ded?µ???? DLCI, Data
  Link Connection Identifier).

115
DLCIs
116
Virtual Circuits and Frame Relay Virtual
Connections
(X.25)
117
?? Hellaspack II

• ???a ?d??µata (????te??e??, ?a?. ??????,
  ??????µ??? ?a?.) µet????? st? p???t??? Frame
  Relay (HELLASPAC II) t?? ??? t? ?p??? st??
  pa???sa f?s? pa???e? p??sßas? 2 Mbps st? ??????
  ???t?? ??e??a? ?e???????a? (???? - Grnet) µe
  d?e??? s??des? 2 Mbps st? Internet (µ?s? t??
  ????pa???? f???a DANTE, pa????? ?p??es???
  Internet se ?????? ??e???t??? d??t?a).

118
???t?a Frame Relay

• G?a t?? p??sßas? µ?s? e??? t?p???? d??t??? se
  d??t?? Frame Relay apa?te?ta? µ?s??µ??? ??f?a??
  ??aµµ? ??a t?? s??des? µe t?? p??s??ste?? ??µß?,
  d??µ?????t?? µe ???ta Frame Relay ?a? s?s?e??
  CSU/OSU ??a t?? µetas??µat?sµ? t?? ??f?a???
  s?µat??.
• ? t?µ?????s? t?? ???s?? t?? d??t??? Frame Relay
  e?a?t?ta? ap? t? ep???µ?t? e???? ?????.
• ? ?p??es?a Frame Relay e??a? ??????µ???te?? ap?
  t? ???s? af?e??µ???? ??aµµ??, ?ta? p???e?ta? ?a
  d?as??de???? a??et? t?p??? d??t?a se p?????
  ap?µa???sµ??e? pe??????.
• ?pa?te?ta? ????te?? ????? af?? a??e? µ?a µ???
  ??aµµ? ?1/?1 (µeta?? t?? pe??t? ?a? t?? pa????a
  t?? ?p??es?a?) ??a t? s????? t?? apa?t??µe???
  ??aµµ??.
• ? f???a? t?? ?p??es?a? e??a? ?pe?????? ??a t?
  d?a?e???s? ?a? ?a?? ?e?t?????a t?? d??t??? Frame
  Relay, a?t??eta µe t?? af?e??µ??e? ??aµµ??, ?p??
  ?pe?????? e??a? ? ???st?? - pe??t??.

119
???t?a ATM

• ?p?te???? ??a d?aded?µ??? t?p? d??t???.
• ????? s?ed?aste? ??a ???t???? ap?st?se?? (p.?.
  ??afe?? ? ?t????), ?s? µa?????? (d?e??e?? ?a?
  d??pe???t???? s??d?se??). ??t? s?µa??e? p?a?t???
  e???e??? µe????? µ????? t?? ?p?d?µ?? p??
  apa?te?ta? s?µe?a ??a ?a s??e??????ta? a?µ?????
  ta t?p??? d??t?a (LAN) µe ta d??t?a µe?????
  ap?st?se?? (WAN) ? ?a? ta µ?t??p???t??? d??t?a
  (MAN).
• St??????ta? st?? as??????? µet?d?s? pa??t??
  (cell) 53 byte.
• ???s?µ?p????? t? µ??t??? a?af???? B-ISDN ATM.

120
???t?a ???

• ?? ??? da?e??eta? st???e?a ap? t??a d?ad?????
  ep?peda st?? ?e?a???a OSI
• t? de?te?? (ep?ped? s??des?? ded?µ????), ??at?
  ß??s?eta? a???ß?? p??? ap? t? ????? ?a? µ???e?
  ?ate??e?a? µe a?t?,
• t? t??t? (ep?ped? d??t???), ??at? t??p?p??e? t?
  s?µpe??f??? t?? µe t?? ??e??? ???? ?a? t?
  d??aµ??? d??µ?????s? ?a? ???µ??eta? ???sa?µ????
  ??? (???s?µ?p??e?ta? ??a t?? s??a?µ?????s?
  ap?s??a?µ?????s? µ????te??? / µe?a??te??? pa??t??
  ?ta? ??e???eta?) ?a?
• t? t?ta?t? (ep?ped? µetaf????), ??at? ??
  s??d?se?? e??a? ?a????sµ??e? ap? s?µe?? se s?µe??
  ?a? ????? a??? ?a? t???? (ep?ped? ???).
• O? ?e?t?????e? t?? ep?p?d?? µetaf????
  ?p?d?a?????ta? se d?? ep?peda
• t? VC (Virtual Channel) ep?ped? ?a?
• t? VP (Virtual Path) ep?ped?.
• ?a d?af??et??? ???t? ?a????a VCs, d?a??????ta?
  ap? t? a?a?????st??? VCI (Virtual Channel
  Identifier).

121
?fa?µ???? t?? ???

• ?? ?????te?e? efa?µ???? st?? ?p??e? ? te???????a
  ??? µp??e? ?a ???s?µ?p????e? e??a?
• ??f?a?? t??e??as?
• ???es??d??s?e?? (Video Conferencing)
• S??d??s?e?? ap? ??afe?? se ??afe?? (Desktop
  Conferencing)
• ??????t???f??? (Videophone)
• ?????a / ???? ?at? pa?a??e??a (Audio/Video On
  Demand)
• ???????? t?p??? d??t?a (VLAN Virtual LANs)
• ?p????????e? ??? µe????? ????t???t?ta? µe
  ????t??? ??µß??? (s?????? µe d???f?????? ?e??e??)

122
???t?a ATM

• ???s? se d??t?a d?a???? ?a? da?t????? µe ???p???
  d???e?s?? (p??t?pa 802.4 ?a? 802.5).
• S?µe?a ta ATM de? ???s?µ?p?????ta? ?? t?p???
  d??t?a, a??? ?????? ??a p???p?e?? sta DSL d??t?a,
  ta ?p??a ????? ?aµ???? apa?t?se?? se ???µ?
  µet?d?s?? ?a? ?p?st??????? t? p??t?????? IP (?a?
  t?? IP ?p??es?e? ?p?? t? VoIP) µ?s? t?? PPP over
  ATM ?a? t?? Ethernet over ATM (RFC 1483).

123
?ef. 6 S?s?e??? t??ep?????????? ?a? d??t??s??
124
S?s?e??? t??ep?????????? ?a? d??t??s??

• ??? ?/? s?st?µata µp????? ?a s??de????
  ???s?µ?p????ta?
• Se???a?? ? pa??????? ???a ep????????a?
• ??a-ap?d?aµ??f?t?? (?odems)
• ???te? d??t??? (NICs)
• ??a??µe?? (Hubs)
• ?pa?a??pte? (repeaters)
• G?f??e? (bridges)
• ???µ?????t?? (routers)

125
S?s?e??? t??ep?????????? ?a? d??t??s??

• Se???a??/pa??????? ???a
• ???t?µ?ta? ?ta? ?? ?/? e??a? p??? ???t?
• ?p?te?e? ??a f???? t??p? d?as??des??
• ???s?µ?p??e?ta? ?ta? ?? apa?t?se?? se ta??t?ta
  e??a? µ?????
• ?p??e? ?a ft?se? t? 1 Mbps.
• ?a modems
• ???a? ?e???? s?s?e??? p?? ep?t??p??? t?? µet?d?s?
  ded?µ???? µ?sa ap? ??aµµ?? p?? de? e??a?
  s?ed?asµ??e? e?d??? ??a t? s??p? a?t?.

126
S?s?e??? t??ep?????????? ?a? d??t??s??

• ?? ???te? d??t??? (NIC- Network Interface Cards)
• ?e?t??????? st? f?s??? ep?ped?
• ???a? s?ed?asµ??e? ??a s???e???µ??? t?p? d??t???
  ?a? s??des?? (?a??d?? ? as??µate?).
• ?a???????? t?? µe??d? p??sßas?? st? µ?s?, s?µf??a
  µe ta p??t?pa ????-802.?.
• ????? ??a? a???µ? t?? ???? (MAC Address),
  d?af??et??? ??a ???e ???ta, ? ?p???? t?p??eta?
  p??? t?? p.?. 08002002904C.

127
S?s?e??? t??ep?????????? ?a? d??t??s??

• ?? ??a??µe?? (Hub)
• ??????? ??a ta ?a??d?a p?? p???????ta? ap? t???
  sta?µ??? e??as?a? se ??a ?e?t???? s?µe?? ? ??µß?.
• ???e e?se???µe?? s?µa eµfa???eta? se ??e? t??
  e??d??? t?? hub (a?t? e??a? ?a? ? ßas??? t??
  d?af??? µe t? Switch).
• ?? d?a??µe?? d?a??????ta? st?? ?at?????e?
• ?a??t???? d?a??µe?? (µe µ???? a???µ? ?????,
  ????? t??f?d?s?a.
• ??e???t???? d?a??µe??.

128
S?s?e??? t??ep?????????? ?a? d??t??s??

• ?? ?pa?a??pte?
• ?? ?????µe e?te ?a ste????µe t? s?µa t?? t?p????
  d??t??? se ap?stas? µe?a??te?? t?? 300 µ?t??? ?
  ?a s??d?s??µe d?? t?p??? d??t?a µeta?? t???
  p??pe? µe ??p??? t??p? ?a a?ad?µ??????s??µe ?a?
  e??s??s??µe t? s?µa.
• ? ?e?t?????a t?? epa?a??pt? (a?ad?µ??????a
  e??s??s? s?µat??) e?s?µat??eta? se p?????
  d??t?a??? s?s?e??? p????, ?p?? e??a? p?. ??
  d?a??µe?? (e?e????) ?a? ?? ??f??e?.
• ?? epa?a??pte? (??? ?? ???p???) ?s? ?a? ??
  d?a??µe?? ?e?t??????? st? f?s??? ep?ped? t??
  a???te?t?????? OSI.

129
S?s?e??? t??ep?????????? ?a? d??t??s??

• ?? G?f??e?
• ?e?t??????? ?a? st?ep?ped? t?? ??aµµ?? ded?µ????
• ???a? ???p?e? s?s?e??? (d?a??t??? epe?e??ast? ?a?
  µ??µ?).
• G???????? (a??? ?a? µa?a?????) t? d?µ? t??
  d??t???.
• ?a?????? ap?f?se?? ??a ta p?a?s?a (??? pa??ta)
  p?? pe????e µ?sa ap? a?t??, ??at? ?ata?aßa?????
  ta p?a?s?a µetaf???? t?? pa??t?? ?a? a?????????
  t?? p????f???e? d??µ?????s?? p?? d?a??t???.
• ??a??t??? p??a?a d?e????se?? ??a t??? ?/? t??
  d??t??? p?? a?a?e??eta? (d?af??e?a- µ???s?)
  s??e???.

130
S?s?e??? t??ep?????????? ?a? d??t??s??

• ?? ???µ?????t??
• ?e?t??????? ?a? st? ep?ped? d??t??? t?? OSI.
• ?p?st??????? t?? ta?t?????? s??des? p?????
  d?af??et???? t?p?? d??t???, µe p??a?? d?af??et???
  µ?sa µet?d?s?? (p.?. ?µ?a?????? ?a??d??, UTP ?t?)
• ?p?st??????? p???p???e? d?at??e?? (t?p?????e?)
  d??t??? st?? ?p??e? e??a? p??a??? d?? s?µe?a t??
  d??t??? ?a e?????ta? µe pe??ss?te?e? ap? µ?a
  d?ad??µ?? a??????ta? ?ts? t?? a???p?st?a.
• ? d??µ?????s? t?? pa??t?? ???eta? d??aµ???,
  ?aµß????ta? ?p??? t?? ?at?stas? t?? d??t???
  (s?????e? ????s??, ?a??st???s? ??p.).
• ??a??t??? p??a?e? d??µ?????s??.
• ?? ???? t?? d??µ?????t? µp????? ?a pa????? a??µa
  ?a? ?/? µe ?at?????a p?????µµata p?. ta Win2000
  Server d?a??t??? µ?a ?p??es?a p?? ???eta? Routing
  Remote Access).

131
S??????e? d??t?a??? s?s?e??? (e?t?? ????)

• Sta pa?ap??? ?a p??s??s??µe ???sµ??e? s??????e?
  s?s?e??? d??t??s?? ?p??
• ?s??µate? ???te? (???t?????a 802.11b/g).
• Access points (S?s?e??? ??a as??µat? p??sßas? st?
  d??t??). ?a??pt??? ap?st?se?? µ???? 100m se
  es?te?????? ?????? ?a? 200 se e??te??????
  ep?t???????ta? ta??t?te? µ???? ?a? 54G, ???s?
  p??t??????? 802.11b/g.
• Bluetooth ?a? Ifrared (S?s?e??? as??µat??
  d??t??s?? se µ???? ap?stas?, p?. BLUETOOTH to USB
  ADAPTER ) µe ta??t?te? µ???? 3Mbps ?a? ?????? ???
  100m.
• ??a??µe?? e?t?? ap? Ethernet, USB ?a? mini USB.
• Switches µe µ??µ? Buffer 512KB ??a ???e s?s?e??.
  ?e ???s? e?a?t?µ?t?? ?p?? t? FIBER MODULE µa?
  d????? t? d??at?t?ta ?a epe?te????µe t? d??t??
  µa? µe s??des? t?? se ??a d?a??s?µ? expansion
  slot t?? switch. ?p????µe ?a s??d?s??µe p???ap??
  switches se ap?stas? ??? 2000 µ?t?a µ?s?
  p???t??p?? ?pt???? ???? (p??t?pa IEEE 802.3u,
  ta??t?ta µetaf???? 200Mbps
• Patch Panel

132
?ef. 7 Digital Subscriber Line / DSL (T)
133
??f?a?? G?aµµ? S??d??µ?t? (Digital Subscriber
Line, DSL)

• ???s? ap??? t??ef?????? ?a??d??? (?a????, CAT3)
• ??? 2,3 Mbps ??a t? s??des? Sp?t? -gt ???µ?????t??
• St?? p???? ??? 768 Kbps
• ??? 52,8 Mbps ??a t? s??des? ???µ?????t?? -gt
  Sp?t?
• St?? p???? ??? 8 Mbps
• ????p?e??a FDM
• 50 kHz - 1 MHz ??a ?at?ßasµa (downloading)
• 4 kHz - 50 kHz for a??ßasµa (uploading)
• 0 kHz - 4 kHz ??a ?a??????? t??ef?????? ???se??
• ????p???s? ?a? t?? 1 MHz e????? ????? t??
  t??ef?????? ?a??d???.

134
T?p??? d??ta?? ADSL e??p??sµ?? (Tanenbaum
-Figure 2-29)
135
xDSL

• ADSL (Asymmetric Digital Subscriber Line)
• ???a? ? p?? d?ad?µ??? µ??f? DSL.
• ???a? as?µµet?? te???????a (8 Mbps downstream/ 1
  Mbps upstream), ap? e?e? ?a? t? p???eµa "A" st?
  ADSL, ?ste ? max ta??t?ta ?a e??a? d?a??s?µ? ??a
  "downloading", p?? ap?te?e? ?a? t?? p?? s????
  d?ast????t?ta.
• ???s?µ?p??e? µe??d??? ??f?a??? ??d???p???s?? ?a?
  epe?e??as?a? s?µat?? ??a a???s? t?? pa?ad?s?a???
  ????t???t?ta?.
• ??a?????e? ta ?a????a upstream ?a? downstream ap?
  t? t??ef????? ?a???? (d?a????sµ?? ap? 300 KHz
  µ???? ta 3,5 MHz).

136
xDSL

• HDSL (High bit rate DSL)
• ???a? s?µµet???? te???????a upstream/downstream
  µ???? 2 Mbps.
• ??? 3.5 km ap?stas? µeta?? t?? d?? ????? t??
  ???????? a?????.
• ?pa?te? t?? ?pa??? 2 t??ef?????? ??aµµ?? (2
  s??est?aµµ??a ?a??d?a).
• SDSL (Single line DSL)
• ???a? ?a? a?t? s?µµet???? te???????a
  (upstream/downstream µ???? 2Mbps)
• ??? 3.5 km ap?stas? µeta?? t?? d?? ????? t??
  ???????? a?????.
• ?pa?te? t?? ?pa??? 1 µ??? t??ef?????? ??aµµ??.

137
xDSL

• VDSL (Very high data rate DSL)
• µ???? 52 Mbps downstream ?a? 2.3 Mbps upstream
• 1,5 km ? µ???st? ap?stas? µeta?? t?? d?? ?????
  t?? ???????? a?????.

138
?ef. 8 ??s??µ??e? G?aµµ?? (T)
139
?a??de??µa ???s?? µ?s??µ???? ??aµµ??
140
??s??µ??e? ??aµµ?? ?????µata

• ?? µ?s??µ??e? ??aµµ?? e??a? ?at?????e? ??a
  asfa?e?? s??d?se?? µe sta?e?? ????t???t?ta.
  ??a??????ta? se
• ??a??????? (??aµµ?? M1020) ??a µet?d?s? ded?µ????
• ??f?a???
• Hellascom ?????? t??ep????????a?? d??t??
  µet?d?s?? ded?µ???? ?a? f???? ??a sta?e?? ??f?a??
  ?????µata ap? 2,4 Kbps ???2Mbps. ?????? ??f?a??
  d??t?? µe a????e?s? ?a? d?????s? ?a???.
• HellasStream ?? p?? te????????? p????µ??? d??t??
  ßas?sµ??? st?? ??? te???????a. S??d???e? t?
  µeta????? pa??t?? µe t? µeta???? ?????µat??.
  ?a???? µ???µ?? ?deat?? s??d?se?? ??? 33Mbps ??a
  t? d?as??des? p???ap??? s?µe??? (n-tier). ?p?
  64Kbps µ???? 2?bps..
• Hellaspac ??as??des? d??t??? ded?µ???? 2 ?
  pe??ss?t???? s?µe??? (n-tier). ?a??t?te? ap? 300
  bps µ???? 2 ?bps.
• ?p???e? ??µß?? ?a? st?? ??????a.

141
??s??µ??e? ??aµµ?? ?????µata

• ?fa?µ????
• S??des? µe t? t??ef????? d??t??
• S??des? e??? t?p???? d??t???.
• FAX
• ???ed??s?e??
• ?et?d?s? ?at????? e????a?/ ?fa?µ???? t??e?at?????
  (Medical Imaging and Telemedicine).
• ??st?? e??at?stas?? µ?a? µ?s??µ???? ??aµµ??
• ??st?? ??a t???? s??des?? ? µetaf???? a?? ????.
• ??st?? p?? af??? t? µ???a?? µ?s??µa t?? ??aµµ??.
• ?a?????eta? ap?
• Ta??t?ta
• ??p? ??aµµ?? (??a?????? ? ??f?a??) ?a?
• ?? ? s??des? af??? ast???? ? ?pe?ast???? ??aµµ??
• ??de??t??? ??st?? µ?s??s?? ??f?a??? ??aµµ??
  µeta?? 2 ??µß?? p?? ap????? 250 km (p.?.
  ??t?a-????a), ta??t?ta? 34 ?bps ?a? µetaß??t??
  µ?s??µat?? a????eta? sta 4402 ??a t? t????
  s??des?? a?? ???? ?a? sta 16463 ??a t? µ???a??
  µ?s??µa a?? ????.

142
?ef. 10???t?p? ??af???? Open Systems
Interconnection/OSI
143
??epaf??
144
???t??? ??af???? OSI
145
? f???s?f?a ?a? ? ???s? t?? p??t?p??

• ??a e????? ap?de?t? te????? d?µ?s?? se ep?peda.
• ?? ?e?t?????e? ???????ta? se ??a ?e?a????? s?????
  ap? ep?peda.
• ???e ep?ped? s?et??eta? µe ??a ?p?s?????
  ?e?t??????? p?? apa?t???ta? ??a ?a ep????????se?
  µe ??p??? ???? s?st?µa.
• ???e ep?ped? st????eta? st? aµ?s?? ?aµ???te??
  t??.

146
?a ep?peda t?? ???t???? OSI

• F?s??? ep?ped? (Physical Layer)
• ?et?d?s? a?at???ast?? bits (0 ? 1) ap? t??
  ap?st???a st?? d??t?.
• ?p?ped? G?aµµ?? ?ed?µ???? (Data Link Layer)
• ?eµa???e? ta ded?µ??a se p?a?s?a (frames)
• ?p?ßeßa???e? ?t? ? ep????????a e??a? a???p?st?
  (acknowledgement frames)
• ?????e?s? ?a? ep?d?????s? ?a??? (Error detection
  and correction).
• ??e???? ???? (flow control).

147
?a ep?peda t?? ???t???? OSI

• ?p?ped? ???t??? (Network Layer)
• ???µ?????s? pa??t??
• ??e???? s?µf???s??
• ??d?s? ???a??asµ?? (billing)
• ?p?ped? ?etaf???? (Transport Layer)
• ?eµa???e? ta µ???µata se µ????te?e? µ???de?
• ?p?ßeßa???e? ?t? ??e? ?? µ???de? ft????? st? ????
  ???? ?a? epa?as??a?µ????e? t? µ???µa.
• ?p??es?e? µetaf???? pa??t?? ap? ???? se ????
  (end-to-end) (p.?. a???p?st? µetaf???).
• ??e???? s?µf???s?? (congestion) ?a? ???? pa??t??.

148
?a ep?peda t?? ???t???? OSI

• ?p?ped? S???d?? (Session Layer)
• ?p??at?stas? s???d?? µeta?? d?af???? µ??a???
  (sessions)
• ??a?e???s? s??t???? (token management)
• S???????sµ?? (synchronization)
• ?p?ped? ?a???s?as?? (Presentation Layer)
• ??d???p???s? ded?µ????
• ?p?ped? ?fa?µ???? (Application Layer)
• S?µßat?t?ta µeta?? efa?µ????.

149
?a ep?peda t?? ???t???? OSI s???pt???
150
S?????s? t?? µ??t???? OSI-TCP/IP
151
????? µe?a??te??? ap?d???? t?? µ??t???? TCP/IP
??a?t? t?? OSI

• ?? µ??t??? OSI
• ???s?µ?p??e?ta? st? s?ed?asµ? d??t???.
• ???a? ?e???t???, ??? ?d?a?te?a d?aded?µ???.
• ??e?e??e? se ???e ep?ped? e???????.
• ???a? pe??p???? ?a? a???ß?.
• ?p??e?peta? se d??d?s? t?? µ??t???? TCP/IP t?
  ?p???
• ???a? s?et??? ap?? ?a? sta?e??.
• ?p?st????eta? ap? ???e d??t?a?? s?s?e?? ?a?
  ????sµ???.
• ???? se a?t? ßas??eta? ? ?e?t?????a t??
  ??ad??t???.

152
?? ?e?t?????e? t?? ep?p?d?? ??aµµ?? ded?µ????
(1/3)

• St??eta? a??µesa st? f?s??? ?a? t? ep?ped?
  d??t???.
• ???eta? ta ded?µ??a ap? t? ep?ped? d??t??? ?a?
  ?ate????e? t? ????? ??a t? µet?d?s? t???.
• ??µ?????e? ta p?a?s?a µet?d?s??.
• ?p?te?e?ta? ap? d?? ?p?ep?peda
• ??????? ???sßas?? st? µ?s? (MAC - Media access
  control)
• ??????? ??????? G?aµµ?? (LLC - Logical link
  control)
• ?ate????eta? ap? t? a?t?st???? p??t??????.

153
?? ?e?t?????e? t?? ep?p?d?? ??aµµ?? ded?µ??????
?p?ep?ped? MAC (2/3)

• ????e?? t?? e??a? ? ep????????a t?? s?s?e??? µ?sa
  ap? ??a ????? µ?s? p??sßas??.
• ?????e?e?, a??? de? d??????e? ta ????.
• ?a???e? ??a µ??a??sµ? d?e????s??d?t?s?? (MAC),
  d??ad? e??? µ??ad???? 12??f??? se???a??? a???µ??
  (de?ae?ad????) ?????ta? d??at? t?? pa??d?s?
  pa??t?? se ??a ?p?d??t??, t? ?p??? p?. de? ??e?
  router, ?p?? ?a µp????se ?a s?µße? se ??a t?p???
  d??t?? Ethernet.
• ? MAC a???µ?? pa??t? de? p??pe?, µp??e? ?a
  t??p?p????e? (http//www.nthelp.com/NT6/change_mac
  _w2k.htm)

154
?? ?e?t?????e? t?? ep?p?d?? ??aµµ?? ded?µ??????
?p?ep?ped? LLC (3/3)

• ???s?eta? p??? ap? t? MAC.
• ???a? a?e???t?t? ap? t? µ?s? ?a? ??e? ??
  a?t??e?µe?? ?a d?e????s??d?te? ?a? ?a p???p???e?
  se µ?sa p???ap??? p??sßas??, ?p?? a?t? t??
  t?p???? d??t???.
• ?a???e? ??e??? ???? ded?µ????.
• ?????e?e? t?? a??? /t???? t?? µet?d?s??.
• ?pa?a?aµß??e? t?? ap?st??? t?? ap????pt???
  pa??t?? a? ??e?aste?.

155
?? p??t?????? PPP (Point- to - Point Protocol)

• ???a? t? e???te?a a?apt??µ??? p??t?????? ??a t?
  s??des? µ?s? t??ef???? (dial up) (s??des? s?µe???
  p??? s?µe??)
• ??s?ast??? e????a???e? ta TCP/IP pa??ta t??
  ?p?????st?-pe??t? ?a? ta p????e? st?? e??p??et?t?
  µ?s? t?? se???a??? ??aµµ?? ep????????a? (layer
  two -L2-point-to-point links)
• ? e??p??et?t?? ?aµß??e? ta pa??ta ?a? ta p????e?
  st? Internet.
• ???a? full-duplex ?a? µp??e? ?a ???s?µ?p????e? se
  d??f??e? te???????e? f?s???? µ?s?? (twisted pair,
  fiber, satellite).
• ???t?µ?ta? ??a?t? t?? p??t??????? Serial Line
  Internet Protocol (SLIP), af?? µp??e? ?a
  ?e???ste? as??????? (asynchronous) ?a? s???????
  (synchronous) ep????????a, ?a d?aµ????se? µ?a
  ??aµµ? se p?????? ???ste? ?a? se a?t??es? µe t?
  SLIP, d?a??te? a?a?????s? sfa?µ?t??.

156
?? p??t?????? PPP (Point- to - Point Protocol)

• Flag ?a?a?t??a? s???????sµ??
• Protocol LCP, NCP, IP ? IPX
• To PPP ep?t??pe? st?? ap?st???a ?a? t?? pa?a??pt?
  ?a d?ap?a?µate????? t? µ??e??? t?? d?af????
  ?a?a?t????.
• ?? p?a?s?? PPP e??a? ???pt???af?µ??? µe Microsoft
  Point-to-Point Encryption (MPPE) ???s?µ?p????ta?
  ??e?d?? ???pt????f?s?? p?? d?µ?????????a? ap?
  d?ad??as?e? a??e?t???p???s?? MS-CHAP
  (???s?µ?p??e? ?e??a??a t???? d?ad??µ??
  (three-way), MS-CHAP v2 ? EAP-TLS.

157
?? p??t?????? PPP (Point- to - Point Protocol)

• ???s?µ?p??e?ta? e????? ??a t?? s??d?se?? st?
  d?ad??t??.
• ?p?t??pe? t?? d?a????sµ? t?? p?a?s???
• LCP (Link Control Protocol) ?p?st????e? t??
  a?t?µat? e?e???p???s? ?a? ape?e???p???s? t??
  ?e??e??
• NCP (Network Control Protocol) ?a???e? ?p??es?e?
  st? ep?ped? d??t???, p.?., d?ap?a?µate?eta? t?
  d?e????s? IP.

158
?a p??t?????aPPPoA ?a? ?????

• ? d?af??? ß??s?eta? st? p?? pe?????f??ta? ta
  ded?µ??a ?at? t? µetaf??? t??? a??µesa st? DSL
  Modem ?a? to dslam t?? ISP, st? aµ?s?? ?aµ???te??
  ep?ped? ap? t? IP st? Data Link layer.
• ?e t? PPPoA ta PPP pa??ta e????a?????ta?
  ape??e?a? se pa??ta ATM (cells), e?? µe t? PPPoE
  p??ta pe????e???ta? ap? µ?a ep??efa??da PPPoE
  p???e?µ???? ?a µp????? ?a pe??s??? µ?sa ap? ??a
  ethernet d??t??, d????ta? ?ts? t? d??at?t?ta se
  ?p???d?p?te µ?????µa t?? d??t??? ?a s??µat?se?
  ape??e?a? PPP link µe t?? ISP.
• ?e? ??e?? ?a???a ???? ?a ???s?µ?p???se?? PPPoE a?
  s?? a??e? ?a s??d?esa? st? Internet ape??e?a? ap?
  t? DSL Router. ??e? ???µa µ??? a? ???e?? ?a
  ???s?µ?p???se?? ??p??? ???? µ?????µa t?? d??t???
  (p.?. ??a PC) sa? router p???e?µ???? ?a ??e??
  ?a??te?? ??e??? p??? st? traffic -? t???? p??t??
  ??a ?p???d?p?te ???? ?a t? s??d?se?? ape??e?a?
  st? Internet.
• ??af??? st?? a???p?st?a de? ?p???e?, ap?? µe t?
  PPPoA ?a ??e?? ???? ????te?? overhead (8bytes /
  pa??t?, t?p??? ???? st? 0,58). ???? t??
  p??s?et?? header st? PPPoE ???e? p??s??? ??a ?a
  µ? f????? pa??ta µe?a??te?a ap? 1500 bytes, ?a???
  t?s? e??a? t? µ???st? MTU (Maximum Transmission
  Unit) p?? p??ß??pe? t? Ethernet, ?µ?? ???? ??
  routers ?a t? f???t?s??? a?t?µata. ?e p?? ap??
  ????a t? MTU se PPPoE e??a? 1492, e?? se PPPoA
  e??a? 1500.

159
?a p??t?????aPPPoA ?a? ?????

• ?? ????? pa??e? s?????? µe LLC ?a? ta dslam t??
  ISPs p.?. st? Forthnet pa????? µe ?????, e?? t?
  ????? pa??e? µe VX-MUX (Virtual Circuit
  Multiplexing) ? s??t? VX (p?? p??? ??a ta dslam
  t?? ???.
• S?????? a??µa ?a? ?a ß??e?? t? a??p?d? ap? a?t?
  p?? pa??e? ? p?????? p??? ?a d?????e?. ?p??
  ???e?? se ta??t?ta ?a? ep?ßa???eta? ?a? ???? t?
  dslam ,???? t?? ?t? ?a ???e? a??a??? sta pa??ta,
  ??a ?a ?????? a?t? st?? s?st? µ??f?.

160
?ef. 11 ??sa???? st? INTERNET ?a? st?? ?p??es?a
pe?????s?? st?? ?a???sµ?? ?st?/WWW
161
?? d?ad??t??

• ?? ??ad??t?? (Internet) e??a? t? d??t?? t??
  d??t???, st? ?p??? e??a? s??dedeµ???? pa?? p?????
  ?p?????st?? ?a? ep?µ????? d??t?a ta ?p??a µp?????
  ?a ???s?µ?p????? d?af??et??? te???????a ?a?
  ?e?t??????? s?st?µata.

• ?e???aµß??e? s?ed?? t? s????? t?? pa???sµ???
  p???? p????f???a? ?a? p??sf??e? p??????a ap?
  ?p??es?e? ?a? e??a?e?a ep????????a? ?a?
  p????f???s??.

162
??? ?a? p?te ?e????se

• Sta t??? t?? de?aet?a? t?? '60, t? ?p????e??
  ?µ??a? t?? ?.?.?. a??pt??e ??a pe??aµat???
  s?st?µa ep????????a? p?? ???µa??ta? ARPANet.
• ?????? s???dee ta d??t?a ?p?????st?? t??
  st?at??t???? ß?se?? t?? ?.?.?, a??? s??t?µa
  epe?t????e ?ste ?a pe???aµß??e? t?? eta??e?e? ?a?
  ta e?e???t??? ?d??µata p?? e??a? s??s? µe t??
  ?µ??a.
• ?? de?aet?a t?? 1980, a?t? ta s??dedeµ??a d??t?a,
  epe?t????a? e???tata sta pa?ep?st?µ?a ?a? se
  ?????? ???a??sµ???.
• S?µe?a ? ?a???a? ap? t? sp?t? t??.

163
??? e??a? d?µ?µ???

• ?? Internet de? a???e? se ?a???a?, ??te ?a?e??
  ?a?????e? t? e?d??? p????f???e? ?a pe??s??? se
  a?t? ? p?? a?t?? ?? p????f???e? ?a
  ???s?µ?p???????.
• ???a? pa??µ??? µe t? d?e???? t??ef????? s?st?µa
  st? s????? t?? de? e??a? ?d???t?s?a ?a?e??? ?a?
  de? e????eta? ap? ?a???a?, ?p???e? ?µ?? s??des?
  t?t??a ?ste ?a ?e?t????e? ?? ??a µe???? d??t??.
• ??? ??p??? tµ?µa ??e? ß??ß? ?? p????f???e?
  a????????? ???? d??µ? pa?a??µpt??ta? t? ?a?asµ???
  tµ?µa.

164
?? p??sf??e? t? Internet

• ?????f???e?, d?as??das?, e?pa?de?s?, ß?ß??a,
  pe???d???, e?pa?de?t??? ?????, µ??s???,
  ß??te?ta???e?, ?µ???e? ?a? d?a???e??.
• ?ad??f????? ?a? t??e?pt??? ?a????a, ?deat??
  ?????t?te?, p?d?sfa???, ???s?e?a, ????????a,
  pe???????, ?ata?a??t??? a?a?? (????a, pap??ts?a,
  f??µa?a, a?ta??a?t???, e?d? sp?t???,).
• S???t?se?? ???ta?? µe ?????? a????p??? µe ?????
  e?d?af????ta ap? ??? t?? ??sµ?, a??e?a ??a ?a
  µetaf??e? st?? ?p?????st? t?? (?d????? s?s?e???,
  e??e???d?a ???s??).
• ???e?? p?????µµata, e????e?, a??e?a, µ??s???,