2. 1 1 1 Wide Area Networks (WAN) - Synchronous Digital Hierarchy (SDH) AAU Jens H. Sørensen jhaus@tdc.dk 20 Oktober 2005

3. 2 2 Table of Contents Objectives Introduction to WANs Typical WAN Technologies SDH Protocol SDH Equipment SDH Networks SDH Network Management SDH Services (partly 2nd part) WDM/OTN (2nd part) Network availability, restoration and automatic protection (2nd part) Next/new Generation SDH and relations to IP, ATM, WDM, Ethernet … (2nd part) Network Synchronisation (2nd part)

4. 3 3 Objectives Discussion of LAN versus WAN, scaleability issues WAN technologies, overview Typical WANs, examples, SDH Relations to networks based on Ethernet/IP/ATM/DSL … Upcoming WAN networks

5. 4 4 SDH Services

6. 5 5 Leased line Services (fixed dedicated bandwidth): –2 Mbit/s, n x 2 Mbit/s –VC-12, n x VC-12 –34 Mbit/s, 45 M Mbit/s –VC-3, n x VC-3 –140 Mbit/s –VC-4 –VC-4-4c, VC-4-16c –Grey fibres / WDM channels add-on services –Alternative routing, Specific routing, automatic protection, various Service Level Agreements (SLAs)

7. 6 6 SDH services - Users

8. 7 7

9. 8 8

10. 9 9

11. 10 SDH services - Users

12. 11 Wavelength Division Multiplexing (WDM)

13. 12 WDM systems Passive WDM system - no active electronics - Reach up to appr. 40 km - no e2e management Optical amplified WDM system - Optical amplifiers (end points) - Optional mid-span optical amplifiers - Typical reach up to 700 km - e2e management possible WDM system characterisation - Number of possible channels - No. of channels in use - A channel can be inegrated or open - Geografical reach measured in no. of spans (= mid span amplifiers + 1) WDM på 5 min

14. 13 WDM network, 4 STM-N Rings

15. 14 WDM, OTN WDM –Dense WDM –Coarse WDM Optical Transport Networks, OTN –Direct switching of optical signals with specific wavelengths –Optical ADM –Optical XC

16. 15 Network Availability, Restoration and Automatic Protection the five 9’s (99,999%)

17. 16 Alternative Routing and Protection Costumer address 1 Costumer address 2 Kunde adresse1 Kunde adresse2 Kunde adresse1 Kunde adresse2 Circuits with alternative routes (Costumer initiates protection) Protected Circuit (Service provider responsible for circuit protecion via costumer based equipment) Site 1 Site 2 Site 1 Costumer equipment SP equipment ( ) Costumer equipment

18. 17 Alternative Routes, Alternative Sites Circuit with alternative routes (cable) Circuit with alternative routes and sites

19. 18 Protection SNC-PTrail Inherent monitoring Ring Linear Non intrusive monitoring shared dedicated MS VC Classification shared dedicated MS VC

20. 19 Protection af Network Connections Linear protection –1+1 protection (dedicated) –1 : N protection (dedicated or shared) TX RX Working Protecting TX RX Working Protecting TX RX Working

21. 20 SNCP Protection in a sub-net or end-to-end –Operates at SDH path level (VC-12, VC-4) –simple protection (switching in RX equipment) Sub-network Working Protecting Sub Network Connection Protection

22. 21 Protection af Network connections Ring protection TX RX

23. 22 Multiplexer Shared Protection Ring (MSSPRING) NormalCable fault between Node A1 and Node A6

24. 23 Eksempel på SNC beskyttelse

25. 24 Next/new Generation SDH and relations to IP, ATM, WDM, Ethernet …

26. 25 WAN Transport platforms - relations 2 Mbit/s 34 Mbit/s 155 Mbit/s 622 Mbit/s 2,5 Gbit/s10 Gbit/s 40 Gbit/s IP ATM SDH WDM FIBER Packet Over Sonet (POS) with Contiguous concatenation

27. 26 Data and SDH C-3 ( 49.5 Mbit/s) C-3 C-4 ( 149 Mbit/s) C-4-4c ( 599 Mbit/s) C-4-4c C-4-16c ( 2.4 Gbit/s) C-4-16c SDH 20% 50% 67% 33% 67% 33% 42% C-4-64c100% Ethernet ATM ESCON Fibre Channel Fast Ethernet Gigabit Ethernet Data 10 Mbit/s 25 Mbit/s 200 Mbit/s 400 Mbit/s 800 Mbit/s 100 Mbit/s 1 Gbit/s 10 Gb Ethernet10 Gbit/s Efficiency Transport "efficiency" Solution: Virtual Concatenation

28. 27 Next Generation SDH Virtual Concatenation Generic Frame Procedure (GFP) Link Capacity Adjustment Scheme (LCAS)

29. 28 LSP 1 LSP 2 LSP 1 VCX/ VCG VC-n 1 VC-n 2 STM-N Virtuel multiplexing of a block of VC-n's (VCG) VC-n 1 VC-n 2 VCX/ VCG LSP 1 LSP 2 LSP 1

30. 29 C-n-Xc C-n 1 2 X X  VC-n = VC-n-Xv Virtual Concatenation VC-n-Xc transport through a VC-n only network 29

31. 30 Virtual Concatenation C-12-5c C-12-12c C-12-46c C-3-2c C-3-4c C-3-8c C-4-6c C-4-7c SDH 92% 98% 100% 89% 95% C-4-64c100% Ethernet ATM ESCON Fibre Channel Fast Ethernet Gigabit Ethernet Data 10 Mbit/s 25 Mbit/s 200 Mbit/s 400 Mbit/s 800 Mbit/s 100 Mbit/s 1 Gbit/s 10 Gb Ethernet10 Gbit/s Efficiency Transport efficiencies 30

32. 31 Mapping Data SDH, SONET and OTN provide fixed rate channels, with virtual concatenation and LCAS to provide the best match 31 to map the different types of Data into a fixed rate channel a new mechanism is defined: Generic Framing Procedure (GFP) i.e. ITU-T recommendation G.7041/Y.1303 GFP is a generic mechanism to carry any packet signal (Ethernet, Fiber channel, ESCON) over fixed rate channels VC-n, VC-n-Xc, VC-n-Xv and LCAS providing flexible adjustment of a VC-n-Xv channel most Data transport is packet based

33. 32 Generic Framing Procedure 32 EthernetIP/PPP Fibre Channel FICONESCON other client signals SDH/SONET pathOTN pathother CBR path GFP - Client Specific Aspects (payload dependent) GFP - Common Aspects (payload independent)

34. 33 Link Capacity Adjustment Scheme (LCAS) Bandwidth can dynamically change (eg. nxVC- 12, nxVC-4) "Hitless" change og bandwidth Automatic adjustment of bandwidth in case of failure in one or more VC-n’s Different up- og down bandwidth is supported The combination of LCAS and VC enables ”cheap” protection

35. 34 Upcoming WANs

36. 35

37. 36

38. 37 Network Synchronisation

39. 38 Consequences in case of lack of synchronisation Slip rate = clock offset x frame rate x 86400 (s) pr. day For 2Mbit/s signals, frame rate = 8K frames/s : ­ 10 -11 = 1 slip in 4.8 months ­ 10 -10 = 1 slip in 14.5 days ­ 10 -9 = 1 slip in 1.45 days ­ 10 -8 = 6.9 slips per day ­ 10 -7 = 2.9 slips per hour ­ 10 -6 = 28.8 slips per hour ­ 10 -5 = 4.8 slips per minute

40. 39 Necessary accuracy 1 sec per day~1 / 86.400 = 11,6·10 -6 Equipment in hold-over~4,6·10 -6 SASE oscillator~2·10 -10 Cæsium modul~< 1·10 -11 (10 -10 svarer til en nøjagtighed på ½ cm på jordens omkreds)

41. 40 The effect of Slips Tale –Uncompressed - 5% slips medfører hørbare klik –Compressed - et slip vil medføre hørbart klik Fax –Et slip kan fjerne flere linier Modem –Et slip kan medføre adskillige sekunders drop out Compressed video –Et slip kan fjerne flere linier –Flere slip kan fryse billedet i sekunder Encrypted/compressed data protokol –Slip medfører reduceret båndbredde

42. 41 Netopbygning NATIONALT NETLAG REGIONALT NETLAG LOKALT NETLAG Primær forbindelse Sekundær forbindelse SASEclockG.812 SASEclockG.812SASEclockG.812SASEclockG.812 SASEclockG.812 SASEclockG.812 SASEclockG.812 SASEclockG.812 SASEclockG.812 SASEclockG.812SASEclockG.812 STM-N STM-N STM-N PRCG.811

43. 42 Referencer Tidsenhed - sekund (SI-enheden for tid) ”The second is the duration of 9.192.631.770 periods of the radiation corresponding to the transition between the two hyperfine levels of the fundamental state of the Cesium 133 atom” Tidligere anvendte man et sekund defineret som tiden for én jordrotation divideret med 86.400.

44. 43 Referencer (4) GPS princip 4 satellitter nødvendig for (x, y, z, t)