Digital Subscriber Line

1
Digital Subscriber Line

• ?e???????e? ??ad??t??? ?a? ???t??? ???e?a? ?????

2
??????????? ?p??es?e?

• ????p?st? ?a? d?a???? s??des? st? internet
• ?????? ta??t?te? µetaß?ßas?? ded?µ????
• ?etaf??? p???µes???? pe??e??µ????
• Yp??es?e? ?????ep?d?as??
• ?????µ??e? ?p??es?e? ep?????????? ?a? ße?t??s?
  t?? s??s?? µeta?? ???t???p???t?-ep??e???se??
  eHealth, eGovernment, eLearning, eBusiness

3
?e???????e? ??????????? ???t???

• ??p???? ß????? (Local Loop, Last Mile)
• ???t?a
• ???µ??
• ??e?t???? ???, Gigabit Ethernet
• ?pt??? DWDM
• ???????µat??? LMDS/MMDS/WiMAX
• ???sßas??
• ?e???????e? p??sßas??
• ??s??µate? xDSL, Fiber optic, Powerline, Cable
• ?s??µate? UMTS, WiFi / WiMax, Satellite

4
?e???????a xDSL (1)

• ??p???? ß??????
• S??est?aµµ??a ?e??? ???????? ?a??d??? t??ef???a?
• ?a?t?????? µet?d?s? ded?µ???? ?a? f????
• ??µet???e?s? t?? a???s?µ?p???t?? f?sµat??
  s????t?t?? st?? d?s??µate? ??aµµ??
• ?a?a?t???st???
• ?a??t?ta µetaf???? ded?µ????
• ??????
• ????? s?????t??s?? (Contention ratio)

5
?e???????a xDSL (2)

• xDSL
• S?µµet????? ?d??? ???µ?? ????? ?a? ap?st????
  ded?µ????
• ?s?µµet?e? ? ta??t?ta µe t?? ?p??a ? ???st??
  µp??e? ?a ??ße? ded?µ??a e??a? µe?a??te?? ap?
  a?t? µe t?? ?p??a µp??e? ?a ap?ste??e? ded?µ??a.
• ??a??p?????ta? ßas???? efa?µ???? t?? internet
  ?p?? pe?????s?, ????/ap?st??? ??e?t???????
  ta??d??µe???, ???? µ??s???? ?.?.p.
• Splitter-based apa?te?ta? ? e??at?stas? e???
  d?a????st? s?µat?? (splitter) st? ???? t??
  s??d??µ?t?, ??a t?? d?a????sµ? t?? s?µat?? t??
  f???? ap? t? s?µa p?? µetaf??e? ta ded?µ??a
• Splitterless de? apa?te?ta? ? e??at?stas? e???
  d?a????st? s?µat?? st? ???? t?? s??d??µ?t?, ?
  d?a????sµ?? t?? s?µat?? ???eta? ?e?t???? st??
  e??atast?se?? t?? t??ef?????? eta??e?a?

6
?st????? St???e?a - ADSL
1994 1995 1998 -- 1999 2002 2003
2004 2006 --
DSL Forum
????????s? t?? DMT ?a? CAP ??a ADSL
ANSI T1.413 ITU-T ADSL standards G.992.1
(G.full 8M/640k) ?a?G.992.2 (G.lite 1.5M/512k)
ADSL2 (G.992.3) ?a? (G.992.41) ADSL2
(G.992.5). VDSL (G.933.1) VDSL2 (G.933.2)
7
??p?? xDSL ?a? Standards

• ?????te?e? te???????e? xDSL
• ADSL ?symmetric Digital Subscriber Line (ANSI
  TI.413 - ITU G.992.1)
• ADSL lite (ITU - G.992.2)
• ADSL2 (ITU - G.992.3 - G.992.4)
• ADSL2 (ITU - G.992.5)
• HDSL High-bit-rate Digital Subscriber Line (ITU
  - G.991.1)
• SHDSL Symmetric High-bit-rate Digital
  Subscriber Line (G.991.2)
• VDSL Very-high-data-rate Digital Subscriber
  Line (ITU G.993.1)
• VDSL2 Very-high-data-rate Digital Subscriber
  Line (ITU G.993.2)

8
??p?? xDSL - ?a?a?t???st???
xDSL ?e????af? ???µ?? ?ed?µ???? ???µ?? ?ed?µ???? ?p?stas?
xDSL ?e????af? upstream downstream ?p?stas?
ADSL Asymmetric Digital Subscriber Line 64640 kbps 1.5 - 8 Mbps 1.544 Mbps - 5.5 km 2.048 Mbps - 4.8 km 6.312 Mbps - 3.6 km 8.448 Mbps - 2.7 km
ADSL lite Splitterless Asymmetric DSL 512 Kbps 1 Mbps 5.5 km
ADSL2 Asymmetric Digital Subscriber Line 2 1 - 3.5 Mbps 12 Mbps lt 6 km
ADSL2 Asymmetric Digital Subscriber Line 2 1 - 3.5 Mbps 24 Mbps lt 6 km
HDSL Symmetric High bit-rate Digital Subscriber Line (uses 23 wire pairs) 1.544 Mbps full duplex (T1) 2.048 Mbps full duplex (E1) 1.544 Mbps full duplex (T1) 2.048 Mbps full duplex (E1) 1.544 Mbps - 5.5 km 2.048 Mbps - 3.6 km
SDSL Symmetric DSL (uses 1 wire pairs) 1.544 Mbps full duplex (T1) 2.048 Mbps full duplex (E1) 1.544 Mbps full duplex (T1) 2.048 Mbps full duplex (E1) 3 km (UTP)
VDSL Very high rate Digital Subscriber Line 1.5 - 2.3 Mbps 13-52 Mbps asymmetric 26 Mbps symmetric 12.96 Mbps - 1.4 km 25.82 Mbps - 0.9 km 51.84 Mbps - 0.3 km
9
S?????s? ap?d?s??
0 0.6 1.2
1.8 2.5 3.0
3.6 4.3 4.9
5.5 6.0
Distance/km
Reference DSL Forum DSL Anywhere - Issue 2,
Sep. 04
10
ADSL S?µe?a

• ???O ??? 100.000.000 G?aµµ??
• ?a?????? ?a? ???µ? ?e???????a
• ? ?fa?µ??? t?? ??t??e?µe?? ????t???? S?ed?asµ??
• ??t?µet?p??eta? ?? ?p?d?µ?
• ????? p?s?st? t?? ?a???sµ?a? ??????????t?ta?
• ????? ??a?es?µ?t?ta st?? ??ept??µ??e? ???e?
• ?e???µe?e? ??µ??
• ?fa?µ????
• Internet
• F???
• Video
• St?? ?p??es?a
• ?d??t??
• ?p??e???se??
• ??at???? F?????
• ??pa?de?t???? ???a??sµ??
• ????s?
• Sta?e??
• ?e t?? ???? t?? ?ed?µ????

11
??T??? ???????O?
VoIP 8-64 Kbps ??????s? st??
?st? 1Mbp s F?t? 5Mpixel se 10s 1.5
Mbps SDTV (Mpeg4) 1.5 Mbps SDTV (Mpeg2) 4
Mbps HDTV (Mpeg4) 7-9 Mbps HDTV
(Mpeg2) 15 Mbps
12
ADSL Ge???a (1)

• ?p??es?e? ?????? ta??t?t?? µ?s? UTP
• ???ef???a, ????µ?sa ?a? ded?µ??a p??? ap? µ?a
  d?s??µat? ??aµµ?
• ?et?d?s? f???? lt 4KHz
• ?et?d?s? ded?µ???? 25KHz 1.1 MHz

13
ADSL Ge???a (2)

• ?e?µa ded?µ???? ?????? ???µ?? (downstream) ap?
  ??p??? ???t?? (Local Exchange/Central Office)
  p??? s??d??µ?t?
• ?e?µa ded?µ???? ?aµ???te??? ???µ?? (upstream) ap?
  s??d??µ?t? p??? ??p??? ???t??
• F?s??? ?p?ped?
• ??µ? p?a?s???
• ??aµ??f?s?
• ??d???p???s?
• ????p?e??a

14
????te?t????? ADSL (1)
15
????te?t????? ADSL (2)
16
????te?t????? ADSL S??d??µ?t??(1)

• ???p??sµ?? s??d??µ?t? (Broadband Network
  Termination)
• ADSL modem/router (ATU R)
• ??a????st?? s?µat?? ? f??t?a
• ??a????st?? s?µat?? d?a?????e? t? t??ef????? s?µa
  ?a? t? ???s???? s?µa ??a t? ADSL modem.
• ?? s?µa e??d?? ap? t? ?DSL modem t?? s??d??µ?t?
  ?a? t? t??ef??? µetad?deta? µ?s? t?? d?s??µat??
  ??aµµ?? ?? e??a?? s?µa p?? µetaf??e? ded?µ??a ?a?
  t??ef???a

17
????te?t????? ADSL S??d??µ?t??(2)

• ?? ADSL s?µa d?a?????eta? st? t?p??? ???t?? µe t?
  ???s? e??? d?a????st? s?µat??
• ?? s?µa e??d?? ded?µ???? te?µat??eta? st? ATU-C
  t?? ??f?a??? p???p???t? p??sßas?? (DSLAM ? Access
  Node) ?p?? ap???d???p??e?ta? se ??f?a?? µ??f?

18
????te?t????? ADSL (2)
19
????te?t????? ADSL DSLAM (1)
??µß?? ???sßas??

• ????a ?a?a?t???st??? DSLAM
• ????µ?? p??t?? DSL
• ??epaf?? d??t???
• DSLAM
• Splitters, ATU-C (ADSL modems
• st? t?p??? ???t??), Network Interfaces ??a
• ?a s??d?eta? st?? ????? ???µ? t?? d??t???
• (p? ATM, GE p??? ap? OC-3 /STM-1)

20
????te?t????? ADSL DSLAM (2)

• line termination cards, ATM point to multipoint
  bus, ATM switch, network termination card
• ? ??? ded?µ???? ap? ?a? p??? ta ATU-C
  p???p???eta? ap?p???p???eta? µ?s? t?? ATM bus se
  VC-VPs (Virtual channel Virtual paths) p??? t?
  network interface
• ?? ATM bus ep?t??pe? t?? p???p?e??a
  ap?p???p?e??a t?? d?af???? VC-VPs se d??f?????
  ???µ??? µet?d?s?? ded?µ???? p??? ta d??f??a ATU-C
  
• ???e ATU-C ??e? t?? d??at?t?ta ?a d???e?e? se
  d?af??et??? ???µ? µet?d?s?? ded?µ???? s?µf??a µe
  t? p??f?? t?? ???e te????? ???st? ?a? t?? f?s????
  ????? t?? ?a?a????

21
????te?t????? ADSL DSLAM (3)

• e.g. X DSLAMs provides scalable 48 port density
  options to meet the needs of smaller deployments
  both in-building and in remote cabinets. The
  Raptor XP family includes support for FE/GE
  uplinks and 48 ADSL2 ports with or without
  built-in splitters. The Raptor XP also supports a
  full suite of Layer 2 and Layer 3 capabilities.

22
????te?t????? ADSL ???t?? ???µ?? (1)

• ?? ???? t?? bit ap? ???e DSLAM p???p?????ta? ?a?
  µetad?d??ta? µ?sa ap? t? ?e??t??? d??t?? (trunk
  network), st? s?µe?? pa???s?a? (Point of
  Presence) t?? pa????? (ISP).
• St? s?µe?? pa???s?a? ? ??? t?? bit
  ap?p???p???eta? se ?e????st?? ???? ?a?
  µetad?d??ta? e?te se t?p????? e??p??et?t?? e?te
  se p??e? d?ad??t??? (internet gateways).

23
Protocol stacks ADSL
24
????te?t????? ADSL - RFC 1483

• ???t??? ?e?t?????a? d??µ?????s?? (routed) ?a?
  ?ef???s?? (bridged) Multiprotocol Encapsulation
  over ATM Adaptation Layer 5 -
• ?ridged encapsulation
• An ATU-R acts as a bridge between the Ethernet
  and the wide-area networking (WAN) side.
• CPE 802.3 Ethernet frames are segmented into
  asynchronous transfer mode (ATM) cells through
  ATM adaptation layer 5 (AAL5).
• The receiving equipment is notified of the type
  of protocol segmented into to cells because the
  standard calls appending logical
  linkcontrol/subnetwork access protocol (LLC/SNAP)
  information to the 802.3 frame before its
  segmented into the ATM cells.
• Routed bridge encapsulation
• The packets are not bridged but instead routed
  based on IP header information.

25
????te?t????? ADSL - RFC 1483
26
????te?t????? ADSL M??t??? s?????t??s??
te?µat???µe??? PPP s??d?se?? p??? ap? ATM
27
????te?t????? ADSL M??t??? s?????t??s??
te?µat???µe??? PPP s??d?se?? p??? ap? ATM

• The ATU-R encapsulates IP packets into PPP frames
  and then segments them into ATM cells via AAL5.
  The PPP link is terminated at the BRAS and the
  originating workstations IP packet is routed to
  its final destination through the service
  provider of choice.
• Remote Authentication Dial-in User Service
  (RADIUS) server is used to authenticate and
  authorize the user -gt per session Authentication,
  Authorization, and Accounting (AAA).
• DHCP servers are used to assign the IP address to
  the user.
• A single PPP session per VC.

28
????te?t????? ADSL M??t??? s?????t??s??
te?µat???µe??? PPP s??d?se?? p??? ap? ATM
29
????te?t????? ADSL M??t??? s?????t??s??
te?µat???µe??? PPP s??d?se?? p??? ap? Ethernet

• In the PPPoE architecture, an ATU-R acts as an
  Ethernet-to-WAN bridge and the PPP session is
  established between the end users PC and the
  access concentrator.
• The host encapsulates IP packets into PPP frames.
  PPP frames encapsulated into a MAC frames and
  then bridging the frame over ATM/DSL.
• PPP over Ethernet (PPPoE) provides the ability to
  connect a network of hosts over a simple bridging
  access device to a remote Access Concentrator.
• Each host utilizes its own PPP stack and the user
  is presented with a familiar user interface.
  Access control, billing and type of service can
  be done on a per-user, rather than a per-site,
  basis.
• To provide a point-to-point connection over
  Ethernet, each PPP session must learn the
  Ethernet address of the remote peer, as well as
  establish a unique session identifier. PPPoE
  includes a discovery protocol for this.

30
????te?t????? ADSL M??t??? s?????t??s??
te?µat???µe??? PPP s??d?se?? p??? ap? Ethernet
31
????te?t????? ADSL M??t??? s?????t??s??
te?µat???µe??? PPP s??d?se?? (2)

• ??????????? e??p??et?t?? ap?µa???sµ???? p??sßas??
  (BB-RAS) s???e?t???e? t?? ??????? PPP s??d?se??
  t?? ???st?? ADSL ?a? e??a? ? p??? p??? t? d??t??
  t?? pa????? (ISP)
• RFC 2364 (PPP over AAL5)
• Layer 2 Tunneling Protocol (L2TP)
• LAC (L2TP Access Concentrator)
• LNS (L2TP Network Server)

32
?as??? ????te?t????? ADSL (1)
33
?as??? ????te?t????? ADSL (2)

• ATU-R ADSL Transeiver Unit, Remote end
  (S??d??µ?t??)
• Splitter ??a????st?? s?µat??
• PDN S?st?µa d?a??µ?? ??a t? d?as??des? t??
  µ???d?? ?p??es??? µe t? ATU-R.
• SM (services module) ????da p??sa?µ????
  ?p??es??? (p?. STB, PC interfaces,routers).
• B ?????t??? e?s?d?? ded?µ???? (?p?? s??des? µ?s?
  d???f????), p??? t? µ???da ?p??es??? (p?. Set Top
  Box STB).

34
?as??? ????te?t????? ADSL (3)

• ATU-C ADSL Transeiver Unit, Central Office
  (??p??? ???t??). ? ATU-C µp??e? ?a ß??s?eta?
  e??atest?µ??? st?? ??µß? p??sßas??.
• Access Node ? ??µß?? p??sßas?? ap?te?e?
  ??s?ast??? s?µe?? s?????t??s?? t?s? ??a ta
  ded?µ??a e??e?a? ?s? ?a? ßas???? ?????.

35
?as??? ????te?t????? ADSL (3)

• U ??epaf? ? ?p??a e???e? ta ATU-Rs µe ta
  a?t?st???a ATU-Cs
• VA ?????? d?epaf? a??µesa st? ATU-C ?a? ??µß?
  p??sßas??. ? d?epaf? a?t? µp??e? ?a ???p??e?ta?
  µe s??????? ? as??????? µet?d?s? t?? ded?µ????
  (STM, ATM).
• VC ??epaf? µeta?? t?? ??µß?? p??sßas?? ?a? t?
  d??t?? ???µ??. ?p??e? ?a ???p??e?ta? ap? µ?a ?
  pe??ss?te?e? f?s???? s??d?se??.
• T-SM ??epaf? µeta?? ATU-R ?a? PDN
• T ??epaf? µeta?? PDN ?a? SM.

36
???sßas? st?? ??p??? ß????

• ?e?????? e?????????? p??sßas??
• ?desµ?p???t? p??sßas? st?? t?p??? ß????
  (µe????µe?? ? p?????)
• Bitsream access

37
Local Loop Unbundling

• ?? s?µa??e? ?desµ?p???t? ???sßas? st?? ??p???
  ?????
• ? d??at?t?ta t?? ??µ?µa d??a??????
  t??ep????????a??? ep??e???se?? ?a ???s?µ?p?????
  t?? t?p??? ß???? t?? incumbent (t?? ????a????
  pa??t?, t?? ??? ??a t?? ????da p.?.) ??a t??
  pa???? t??ep????????a??? ?p??es??? st?? pe??t?
• ??? ????eta? ? t?p???? ß?????
• ?? f?s??? ?????µa s??est?aµµ???? ?e?????
  µeta?????? ?a??d??? p?? s??d?e? t? te?µat???
  s?µe?? t?? d??t??? st?? e??atast?se?? t??
  s??d??µ?t? µe t? ????? ?ata?eµ?t? ? µe a?t?st????
  e??at?stas? st? sta?e?? d?µ?s?? t??ef????? d??t??
  t?? incumbent

38
Full Local Loop Unbundling (Full LLU)

• ?????? ?desµ?p???t? ???sßas? (Full Local Loop
  Unbundling)
• Ta ?e??? µeta?????? ?a??d??? e?µ?s?????ta? se
  t??ta µ??? ??a ap???e?st??? ???s?
• ? µ?s??t?? (?e?e?se???µe??? t??ep????????a???
  p??????) ??e? t?? p???? ??e??? t?? t?p???? ß?????
  ?a? t?? s??s?? t?? µe t?? pe??t? t?? ??a t??
  pa???? t??ep????????a??? ?p??es??? µ?s? t??
  ap?desµ?p???µ???? t?p???? ß?????
• To Full LLU ap?te?e? t? d??at?t?ta t?? ??µ?µa
  d??a?????? t??ep????????a??? ep??e???se?? ?a
  ???s?µ?p????? t?? t?p??? ß???? t?? incumbent ??a
  t?? pa???? t??ep????????a??? ?p??es??? st?? pe??t?

39
Shared Local Loop Unbundling

• ?e????µe?? ?desµ?p???t? ???sßas? (Shared Local
  Loop Unbundling)
• ? t?p???? ß????? ???s?µ?p??e?ta? t?s? ap? t??
  incumbent ?s? ?a? ap? t?? ?e?e?se???µe??
  t??ep????????a?? p?????
• ? incumbent e?a??????e? ?a pa???e? t??ef?????
  ?p??es?a e?? ? ?e?e?se???µe??? pa???e? ?p??es?e?
  µet?d?s?? ded?µ???? ?????? ta??t?ta? st?? ?d??
  t?p??? ß????

40
Local Loop Unbundling
Other Local Operators (OLOs) Network
41
Full LLU (Local Loop Unbundling)
?at????s? ?e????
42
Shared LLU (Local Loop Unbundling)
43
LLU ?a? a??pt??? a?ta????sµ??

• ? a??pt??? t?? LLU ?d?a?te?? s?µa?t??? ??a t??
  p?????s? ?a? ed?a??s? t?? a?ta????sµ??
• H a??pt??? t?? LLU ß???? st?? e?sa???? ?a???t?µ??
  e?????????? ?p??es??? (VoIP, IPTV)
• ?? ?e?e?se???µe??? µp????? ?a d?ast????p???????
  a?e???t?ta ap? ta eµp????? p???a t?? incumbent
• ?p????? ?a pa?????? p??sß?se?? xDSL t?? ep??????
  t??? (ADSL, ADSL2, SDSL, VDSL)
• ???at?t?ta d?af???p???s?? a?af????? µe t??
  pa?e??µe?? p???t?ta ?p??es???
• ??af???p???s? ta??t?ta? p??sßas??
• ??af???p???s? p???t???? ?a?a?t???st???? backbone
  d??t???
• ???at?t?ta pa????? ?p??es??? se ?d?a?te?a
  e???st???? t?µ??

44
?a???? Bitstream

• ?? e??a? Bitstream
• ?ta? ? incumbent e??a??st? e??p??sµ? (xDSL) ??a
  t?? pa???? ?p??es??? se te?????? ???ste?
  ?p??es??? ?????? µet?d?s?? ded?µ???? t?te
  ?p???e??ta? ?a d?a??te? t?? a??t??? e??p??sµ? ?a?
  se ?????? t??ep????????a???? ???a??sµ???
  p???e?µ???? ?a µp????? ?a? a?t?? ?a p??sf????? se
  te?????? ???ste? ?p??es?e? ?????? µet?d?s??
  ded?µ???? (p? e????????? p??sßas? st? d?ad??t??)

45
???ef???a Bitstream - LLU
46
???f?? ?a????? Bitstream
47
???f?? ?a????? Bitstream
LLU
48
?a???? Bitstream ap? ???
49
Bitstream ?a? a??pt??? a?ta????sµ??

• ? pa???? Bitstream d?asfa???e? t?? a?ta????sµ?
  t??????st?? se ep?ped? ?p??es??? p??? ?fe??? t??
  te????? ?ata?a??t?? (a?ta????sµ?? se t?µ?? ?a? se
  ???µa ?p??es???)
• ?p?t??pe? ?d??? se µ?????? pa?????? / ISPs ?a
  pa?????? e?????????? ?p??es?e? se te??????
  ???ste?
• ????p??e?ta? se µ???st? ßa?µ? t? ??????? d??t??
  p??sßas?? t?? incumbent operators µe t?? pa????
  xDSL ?p??es??? (?????? ADSL)

50
S?????s? µ??f?? Bitstream (1)

• ?p? Bitstream_5 p??? ?itstream_1 ep?t???????ta?
• ????t?a ??a t?? a??pt??? ?d???t?t?? d??t???
  ???µ?? ap? t??? ????? pa??????
• F????te?? bitstream (t?µ?????? incumbent p???
  pa??????) ?a? ??a p??a??? f????te?? ADSL p???
  ?ata?a??t??
• ?????te??? ßa?µ?? e???t?s?? ap? t?? Incumbent
• ?? bitstream ???eta? pe??ss?te?? a?ta????st???
  st? LLU (t? bitstream_1 µ????e? p??a p??? µe t?
  shared access)

51
S?????s? µ??f?? Bitstream (2)

• ?p? Bitstream_1 p??? ?itstream_5 ep?t???????ta?
• G?????? ?a? e????µ??? e?sa???? ???? te?????????
  (ADSL) ?a? ?p??es??? (fast internet)
• ???µ? ?a? ?? µ????? p?????? ?? ?p???? de?
  d?a??t??? ?d???t?t? d??t?? ???µ?? ??????
  d??at?t?t?? (?a? de? s??pe???? ?a ap??t?s???)
  µp????? ?a pa?????? µ?s? Bitstream ADSL ?p??es?e?
• ?p???e? µe????? a?ta????sµ?? st??? ISP pa??????
  ?a??? de? apa?t???ta? µe???e? epe?d?se?? ??a ?a
  pa?????? ADSL ?a? ep?µ???? s?ed?? ???? ?? ISPs
  µp????? ?a pa?????? ADSL. ??t? ?s?? ep?f??e?
  a?ta????st???? t?µ?? (p??t?te ?µ?? ?a t?? e????e?
  ? incumbent)

52
S?????s? µ??f?? Bitstream LLU ?d???t?t??
?p?d?µ??