Slide 2 1 1 1 Wide Area Networks (WAN) - Synchronous Digital
Hierarchy (SDH) AAU Jens H. Srensen [email protected] 20 Oktober 2005
Slide 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) Slide 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 Slide 5
4 4 SDH Services Slide 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) Slide 7 6 6 SDH services - Users Slide 8 7 7 Slide 9 8 8
Slide 10 9 9 Slide 11 10 SDH services - Users Slide 12 11
Wavelength Division Multiplexing (WDM) Slide 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 p 5 min
Slide 14 13 WDM network, 4 STM-N Rings Slide 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 Slide 16 15 Network Availability, Restoration and
Automatic Protection the five 9s (99,999%) Slide 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 Slide 18 17 Alternative Routes,
Alternative Sites Circuit with alternative routes (cable) Circuit
with alternative routes and sites Slide 19 18 Protection SNC-PTrail
Inherent monitoring Ring Linear Non intrusive monitoring shared
dedicated MS VC Classification shared dedicated MS VC Slide 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 Slide 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
Slide 22 21 Protection af Network connections Ring protection TX RX
Slide 23 22 Multiplexer Shared Protection Ring (MSSPRING)
NormalCable fault between Node A1 and Node A6 Slide 24 23 Eksempel
p SNC beskyttelse Slide 25 24 Next/new Generation SDH and relations
to IP, ATM, WDM, Ethernet Slide 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 Slide 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 Slide 28 27 Next
Generation SDH Virtual Concatenation Generic Frame Procedure (GFP)
Link Capacity Adjustment Scheme (LCAS) Slide 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 Slide 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 Slide 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 Slide 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
Slide 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) Slide 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-ns
Different up- og down bandwidth is supported The combination of
LCAS and VC enables cheap protection Slide 35 34 Upcoming WANs
Slide 36 35 Slide 37 36 Slide 38 37 Network Synchronisation Slide
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 Slide 40 39 Necessary accuracy 1 sec per day~1
/ 86.400 = 11,610 -6 Equipment in hold-over~4,610 -6 SASE
oscillator~210 -10 Csium modul~< 110 -11 (10 -10 svarer til en
njagtighed p cm p jordens omkreds) Slide 41 40 The effect of Slips
Tale Uncompressed - 5% slips medfrer hrbare klik Compressed - et
slip vil medfre hrbart klik Fax Et slip kan fjerne flere linier
Modem Et slip kan medfre adskillige sekunders drop out Compressed
video Et slip kan fjerne flere linier Flere slip kan fryse billedet
i sekunder Encrypted/compressed data protokol Slip medfrer
reduceret bndbredde Slide 42 41 Netopbygning NATIONALT NETLAG
REGIONALT NETLAG LOKALT NETLAG Primr forbindelse Sekundr
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 Slide 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 n jordrotation divideret med
86.400. Slide 44 43 Referencer (4) GPS princip 4 satellitter
ndvendig for (x, y, z, t)
