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)

3.1. Evolution of transport technologies A. Public Network Principles Transport (Core/ Backbone) Network Transmission Network Terminations Access Gateway Wireless Technologies Access Network Twisted Pair Cable/Coax Powerline Optical Fiber Switching/ Routing These 3 techniques will be discussed next

Years Telegraph Manual switching Electro- mechanics AnalogDigital Hand telegraph Operator Cr-B 55 QE 70 DE-1 PABX-1 PABX-2 PABX-NG (IP) Ethernet Gbit Ethernet Private Public ISDN DE-NG (IP) ATM 10 Gbit Ethernet 1884 Self-dial 1935 (B-ISDN) IP /X25/SMDS FR Cellular radio GSM UMTS/IMT-2000 DE-2 NMT B. Evolution of switching technologies G-MPLS MPLS

Switching technologies (Cntd) CS (PSTN) FR (FS, 70-s, DN) IP (PS-DG, 60-s, Internet) Х.25 (PS-VC, 60-s, DN) MS (Tlg) АТМ ( CS, 80-s, B-ISDN) Connection-oriented technologies Connectionless-oriented technologies

ATM IP OB BACKBONE OPTIONS Transport technologies in network backbones MPLS

ATM IP OB BACKBONE OPTIONS C. Transport technologies in network backbones - ATM MPLS

ATM and the IETF model ATM Layer 1/2 Quality of Service (QoS) Multimedia Transport Constant Bit Rate (CBR) - Voice Variable Bit Rate (VBR) - WWW Available Bit Rate (ABR) – Unspecified Bit Rate (UBR) Application Transport Network Data Link Physical

Putting ATM to work Voice Delay Delay Variation Loss Data Delay Delay Variation Loss Video Delay Delay Variation Loss Multimedia Delay Delay Variation Loss

ATM QoS Constant Bit Rate for switched TDM traffic (AAL1): –Access Aggregation (TDM for GSM/GPRS, ATM for UMTS) –Digital Cross-Connect –Backbone Voice Transport - Basic Real-time Variable Bit Rate for bursty, jitter-sensitive traffic: –Backbone Voice Transport – Advanced (AAL2) –Optional for Packetized Access Transport & Aggregation (3G UTRAN, 2G CDMA) Non real-time Variable Bit Rate for bursty high priority data traffic: –2.5G data services Unspecified Bit Rate+ with Minimum B/W Guarantee for internal data : –Operations, Admin & Maintenance (element management, stats collection, network surveillance, …) –Billing data –Internal LAN traffic ( , web, file sharing, …) between operator’s business offices LINE RATE (LR) CBR nrt-VBR ABR UBR UBR+ rt-VBR

ATM’s role in the network’s segments 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 Multimedia Not used much on Premise Present use in Backbone Predictable Performance/Guaranteed QoS

ATM IP OB BACKBONE OPTIONS D. Transport technologies in network backbones - IP MPLS

Network Layer (Layer 3) End-to-End Addressing/Delivery “Best Effort” Service IP and the IETF Model Physical Data Link Network Transport Application IP

Putting IP to work 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 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/Desktop No Real Competition Campus Backbone No Real Competition Access Low Speed (56/64)ISDN Medium Speed (E1)xDSL, non-channelized E1 Integrated AccessE1, multiple E1, Frame Relay, SDH Backbone VoiceTraditional Telephony DataOptical Backbones VideoOptical Backbones MultimediaOptical Backbones, ATM Backbones

Why use IP? -Wide acceptance Internet popularity Global reach - IP Standards Mature standards Interoperability IP Protocol characteristics Simple protocol Good 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 Next Generation Networks Powerful as a computer Mobile as a cell phone and Working right away as a TV set

Main directions of improvement 1. Scalability 2. Security 3. Quality of service 4. Mobility IPv6

ATM IP OB BACKBONE OPTIONS E. Transport technologies in network backbones - MPLS MPLS

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). A B LER LSR LER LSP MPLS Model 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)

ATM IP OB BACKBONE OPTIONS F. Transmission technologies in network backbones - 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 Years Frequency modulation, FDM PDH 1935 Time multiplexing, TDM Wavelength multiplexing Transmission media Modulation methods Frequency modulation systems SDHWDM Copper cable Radio Coax Fiber Optics Satellite radio Radio all optical

Technological limitations of different transmission media Optical fibers are the only alternative at high bandwidth and distances Fiber Coax Cellular Wireless* *Capacity in Mbit/s/sq_km, Bandwidth 500 MHz 250 Copper Twisted Pair

Optical systems move from backbone to access Entry process of optical systems into access occurs very slowly... Prognosis years, reason: exchange of copper cables and maturity of technologies yesterday today tomorrow 5 Years Years Access MetroBackbone Copper Optical ISDN POTS Fiber optics and laser Copper Optical ADSL Optical additional: color filter and optical amplifier additional: optical switch, color converter

Today optical transmission system consists mainly of electronics and passive optical components SDH networks: WDM networks: SignalMultiplexer Cross connector Optical fiber Amplifier TDM MUX TDM MUX, Cross- connect, control Electrical signal Opto- electronics Active optics Passive optics Electronics SDH and WDM process signals most of the time only electronically Amplifiers are the only active optical elements in the network Optical fiber TDM MUX WDM MUX, Cross- connect Electrical signal Active optics Passive optics Electronics WDM MUX Passive optics: - lenses - prisms - grating Control Passive optics: - lenses - grating - mirrors Optical signal

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 Optical fiber Switch Matrix Aktive Optik Passive optics WDM MUX Passive optics: - lenses - prisms - grating Control Active optics: - Switch - color converter - amplifier Optical signal SignalMultiplexer Switch Amplifier

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 Terabits per second. Of that, only 22.6 Terabits per second percent -- of network bandwidth is actually in use Int'l IP Using City Bandwidth, Bandwidth, Gbit/s Gbit/s London ,5 Paris ,3 Frankfurt ,3 Amsterdam ,2

Development of costs for IC sector Source: Economist 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