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3. Evolution of network technologies 3.1. Evolution of transport technologies (backbone transport - switching/routing and transmission systems) 3.2. Evolution of access networks’ technologies to broadband (xDSL, CATV, Broadband Wireless Access)
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3. Evolution of network technologies 3.1. Evolution of transport technologies (backbone transport - switching/routing and transmission systems) 3.2. Evolution of access networks’ technologies to broadband (xDSL, CATV, Broadband Wireless Access) 3.3. Evolution of mobile networks (to 3G and beyond)
Wireless Technologies Optical Fiber Twisted Pair Transport (Core/ Backbone) Network Cable/Coax Powerline Access Gateway Network Terminations Switching/ Routing Transmission Access Network 3.1. Evolution of transport technologiesA. Public Network Principles These 3 techniques will be discussed next
B. Evolution of switching technologies DE-NG (IP) MPLS (B-ISDN) G-MPLS ISDN ATM DE-2 DE-1 1884 Operator FR Public Cr-B QE UMTS/IMT-2000 IP/X25/SMDS Hand telegraph 55 70 Cellular radio Self-dial1935 NMT GSM Ethernet Gbit Ethernet 10 Gbit Ethernet PABX-1 Private PABX-NG (IP) PABX-2 Electro-mechanics Manual switching Telegraph Analog Digital 1840 1900 1950 1975 1980 1990 2000 Years
Switching technologies (Cntd) АТМ (CS, 80-s, B-ISDN) FR (FS, 70-s, DN) Х.25 (PS-VC, 60-s, DN) CS (PSTN) MS (Tlg) IP (PS-DG, 60-s, Internet) Connection-oriented technologies Connectionless-oriented technologies
Transport technologies in network backbones BACKBONE OPTIONS IP ATM OB MPLS
C. Transport technologies in network backbones - ATM BACKBONE OPTIONS IP ATM OB MPLS
ATM and the IETF model • Layer 1/2 • Quality of Service (QoS) • Multimedia Transport Constant Bit Rate (CBR) - Voice Variable Bit Rate (VBR) - WWW Available Bit Rate (ABR) – E-mail Unspecified Bit Rate (UBR) Application Transport Network Data Link ATM Physical
Putting ATM to work 1 2 3 4 5 • Voice • Delay • Delay Variation • Loss • Data • Delay • Delay Variation • Loss • Video • Delay • Delay Variation • Loss • Multimedia • Delay • Delay Variation • Loss
ATM QoS • Constant Bit Ratefor switched TDM traffic (AAL1): • Access Aggregation (TDM for GSM/GPRS, ATM for UMTS) • Digital Cross-Connect • Backbone Voice Transport - Basic • Real-time Variable Bit Ratefor bursty, jitter-sensitive traffic: • Backbone Voice Transport – Advanced (AAL2) • Optional for Packetized Access Transport & Aggregation (3G UTRAN, 2G CDMA) • Non real-time Variable Bit Ratefor bursty high priority data traffic: • 2.5G data services • Unspecified Bit Rate+ with Minimum B/W Guaranteefor internal data: • Operations, Admin & Maintenance (element management, stats collection, network surveillance, …) • Billing data • Internal LAN traffic (email, web, file sharing, …) between operator’s business offices CBR rt-VBR LINE RATE (LR) nrt-VBR ABR UBR UBR+
ATM’s role in the network’s segments 1 2 3 4 5 • Premise • LAN/Desktop • Campus Backbone • Access • Low Speed (56/64) • Medium Speed (E1) • High Speed (>E1 to SDH) • Integrated Access • Backbone • Voice • Data • Video • Multimedia
ATM and the “Competition” • Premise • LAN/Desktop - Ethernet, HS Ethernet, Gigabit Ethernet • Campus Backbone - HS Ethernet, Gigabit Ethernet • Access • Low Speed (56/64) - ISDN, ADSL • Medium Speed (E1) – xDSL, E1 • High Speed (>E1 to SDH) - SDH • Integrated Access - E1, xDSL, SDH • Backbone • Voice Traditional Telephony, IP Backbones • Data Optical Backbones, IP Backbones • Video Optical Backbones, IP Backbones • Multimedia Optical Backbones, IP Backbones
ATM Summary MultimediaNot used much on PremisePresent use in BackbonePredictable Performance/Guaranteed QoS
D. Transport technologies in network backbones - IP BACKBONE OPTIONS IP ATM OB MPLS
IP and the IETF Model • Network Layer (Layer 3) • End-to-End Addressing/Delivery • “Best Effort” Service Application Transport Network IP Data Link Physical
Putting IP to work 1 2 3 4 5 • Voice • Delay • Delay Variation • Loss • Data • Delay • Delay Variation • Loss • Video • Delay • Delay Variation • Loss • Multimedia • Delay • Delay Variation • Loss
IP’s Role in the network’s segment 1 2 3 4 5 • Premise • LAN/Desktop • Campus Backbone • Access • Low Speed (56/64) • Medium Speed (E1) • High Speed (>E1 to SDH) • Integrated Access • Backbone • Voice • Data • Video • Multimedia
IP and the “Competition” • Premise • LAN/DesktopNo Real Competition • Campus Backbone No Real Competition • Access • Low Speed (56/64) ISDN • Medium Speed (E1) xDSL, non-channelized E1 • Integrated Access E1, multiple E1, Frame Relay, SDH • Backbone • Voice Traditional Telephony • Data Optical Backbones • Video Optical Backbones • Multimedia Optical Backbones, ATM Backbones
Why use IP? • Wide acceptanceInternet popularityGlobal reach-IP StandardsMature standardsInteroperability IP Protocol characteristicsSimple protocolGood general purpose protocol“Best Effort” Protocol
IP summary Globally popular Originally developed for data Mature standards Interoperability “Best Effort” Protocol Voice over IP gaining popularity
We need a better Internet Reliable as the phone Working right away as a TV set Mobile as a cell phone and Powerful as a computer Next Generation Networks
Main directions of improvement 1. Scalability 2. Security 3. Quality of service 4. Mobility IPv6
E. Transport technologies in network backbones - MPLS BACKBONE OPTIONS IP ATM OB MPLS
LER B LER A LSR LSR MPLS Model • Routers that handle MPLS and IP are called Label Switch Routers (LSRs) • LSRs at the edge of MPLS networks are called Label Edge Routers (LERs) • Ingress LERs classify unlabelled IP packets and appends the appropriate label. • Egress LERs remove the label and forwarding the unlabelled IP packet towards its destination. • All packets that follow the same path (LSP- Label Switched Part) through the MPLS network and receive the same treatment at each node are known as a Forwarding Equivalence Class (FEC). LSP FEC
E. Switching Technologies - Summary • Driving forces (mid of 80th) - Common platform for different types of traffic • ISDN is not suitable (N-ISDN - low bit rates, circuit switching) • ATM will not become as the most important switching technology since 2000s • Main competitors (Performance/Price) # Ethernet (LANs) # xDSL (Access) # IP/MPLS (Backbones)
F. Transmission technologies in network backbones - OB BACKBONE OPTIONS IP ATM OB MPLS
Stated data rates for the most important end-user and backbone transmission technologies -1
Stated data rates for the most important end-user and backbone transmission technologies -2
Stated data rates for the most important end-user and backbone transmission technologies -3
Stated data rates for the most important end-user and backbone transmission technologies -4
Evolution of transmission technologies Satellite radio Radio Radio Transmission media Coax Coax Copper cable 1935 Copper cable Fiber Optics all optical SDH WDM PDH Frequency modulation systems Modulation methods Wavelength multiplexing Time multiplexing, TDM Frequency modulation, FDM 1900 1970 1980 1990 2000 Years
Technological limitations of different transmission media Fiber 250 Cellular Wireless* Coax Copper Twisted Pair *Capacity in Mbit/s/sq_km, Bandwidth 500 MHz Optical fibers are the only alternative at high bandwidth and distances
Optical systems move from backbone to access Access Metro Backbone Optical Copper yesterday Fiber optics and laser ISDN POTS 5 Years Optical Copper today additional: color filter and optical amplifier ADSL 10-15 Years Optical tomorrow additional: optical switch, color converter Entry process of optical systems into access occurs very slowly ... Prognosis 10-15 years, reason: exchange of copper cables and maturity of technologies
Today optical transmission system consists mainly of electronics and passive optical components Signal Multiplexer Amplifier Cross connector • SDH and WDM process signals most of the time only electronically • Amplifiers are the only active optical elements in the network SDH networks: TDM MUX, Cross- connect, control Optical fiber TDM MUX Passive optics Electrical signal Opto- electronics Active optics Electronics WDM networks: Optical signal Electronics TDM MUX Control Optical fiber Electrical signal WDM MUX WDM MUX, Cross- connect Passive optics Passive optics:- lenses - grating - mirrors Passive optics:- lenses - prisms - grating Active optics
Day after tomorrow:All-optical switching and multiplexing • All-optical systems process signals only optically • Electronics disappear • Nortel (03/2002): large scale stand-alone optical switches are likely for longer term market requirements Signal Multiplexer Amplifier Switch Optical signal Control Optical fiber WDM MUX Switch Matrix Passive optics Active optics:- Switch - color converter - amplifier Passive optics:- lenses - prisms - grating Aktive Optik
Future photonic switches • Optics are good for transport • Electronics are good for switching • Electronics as far as possible Evolution instead of Revolution at least, 5 years for first all-optical systems in backbone and metro area
G. Concluding remarks - growth of network capacity and “Death of distance” phenomenon • Growth of network capacity reduction of information transmission costs • New generation of transmission systems – new ratio Cost of transmission/Bandwidth • PCM SDH/SONET DWDM • Bandwidth becoming a less dominating factor in cost of connection • Cost of one-bit-transmission has an obvious tendency to become very close to zero in long distance communications systems • “Flattened” networks • “Death of distance” phenomenon (F. Cairncross, 1997) • Challenges for operators
Bandwidth using • 32 terrestrial carriers connecting to the New York metropolitan area have a combined potential capacity of 818.2 Terabits per second. Of that, only 22.6 Terabits per second -- 2.8 percent -- of network bandwidth is actually in use • Int'l IP Using City Bandwidth, Bandwidth, Gbit/s Gbit/s London 550.3 9,5 Paris 399.4 9,3 Frankfurt 320.2 10,3 Amsterdam 267.1 8,2
Cost of information processing $ per instruction per second Cost of a three-minute telephone call from New York to London, $ to be continued to be continued Source: Economist Development of costs for IC sector