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Packet Switching

Packet Switching. Tony Rybczynski 23 January 2018 Tonyryb@rogers.com. Tony Rybczynski. B.Eng-EE (McGill) M.Sc- EE (U of Alberta) Life Senior Member of IEEE. 37 years in the industry 10 years with Bell Computer Communications Group as packet switching pioneer

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Packet Switching

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  1. Packet Switching Tony Rybczynski 23 January 2018 Tonyryb@rogers.com

  2. Tony Rybczynski B.Eng-EE (McGill) M.Sc- EE (U of Alberta) Life Senior Member of IEEE 37 years in the industry • 10 years with Bell Computer Communications Group as packet switching pioneer • 4 years in Bell Northern Research in system engineering • 23 years in Nortel Networks mostly in the enterprise business unit • Retired as Director of Strategic Enterprise Technologies (CTO Office) • Over 200 articles, monthly column in trade journal, the ‘Hyperconnected Enterprise’ (TMC) blog and contributor to 2 books • Lecturer in this course since 2000

  3. Outline • Packet technology • The enterprise perspective • Concluding remarks

  4. Why is Packet Switching So Important? Packet switching is the dominant networking technology in the Internet, in public wired and cellular core networks And in wired and wireless home and enterprise networking

  5. Why not Ethernet to where you want to go? Ethernet addressing* is flat! Ethernet networking is not scalable! * 90:21:80:81ff:fedb:637 (in hex)

  6. Why not a fixed circuit to where you want to go? We call that “TDM” or “circuit switching”

  7. Router Router TDM Switch TDM Switch Mux / Demux Mux / Demux Circuit Switching (TDM) vs Packet Switching 56Kbps, T1, T3 56Kbps, T1, T3 TDM on SONET Main differences (TDM vs packet) • Fixed speed vs speed conversion • Fixed delay vs variable delay • Dedicated vs shared bandwidth • Separate vs integrated switching and multiplexing • Call set up vs IP routing 10/100/1000Gbps 56Kbps, T1, T3 IP/fibre Packet Switching is a much more flexible and evolvable technology

  8. Packet Switching Taxonomy Switching & Multiplexing Circuit Switching TDM Multiplexing Packet Switching Statistical Multiplexing Connection- Oriented Connectionless Layer 3 IP Layer 2.5 MPLS Layer 2 Frame Layer 2 Ethernet Copper/fibre MAN/WAN Wired MAN Wireless LAN/MAN • Carriers developed connection-oriented packet services • to meet enterprise needs • to enhance traffic management capabilities

  9. Many Faces of Packet Switching • A set of technologies • Switching & multiplexing architecture • Packet formats • Transportable on different media at varying speeds • LAN/MAN/WAN wired/wireless networks • A service capability • Tarriffed services for consumers and business • Basis for enterprise connectivity • A set of open standards • Interface and networking standards • Unicast and multicast • Service definitions • Performance metrics • Security • Adaptation and encapsulation standards “LAN/MAN/WAN”: Local/Metro/Wide Area Net

  10. Packet Switching: A General Definition • Message or bit stream subdivided into packets • Individually addressed packets provide: • Dynamic bandwidth • Access and trunk multiplexing • Traffic bursts at full pipe capacity • Layered operation with • Application protocols above • Transmission facilities/pipes below • Exploitation of 'bursty' nature and tolerance to delays of most applications • Functionality: routing, flow control, error control, Quality of Service (QoS) …

  11. Packet Switching Time Line Research Nets for robust data comm Ethernet (’80) TCP/IP (’83) Academic Internet Voice and video over IP Mobility ARPAnet (‘72) Commercial X25 nets (‘76) 4G/5G wireless Gaming IPTV Commercial Internet (’94) Frame relay/ATM nets 1960s 1970s 1980s 1990s 2000’s Present IBM PC 1981 iPhone 2007

  12. IP Is THE Network Layer Standard Data Voice Video Multimedia Gaming File sharing IP TV Telemetry Applications Network Layer Layer 4-7 ‘IP Suite’ IP Any Layer 2 Fiber DWDM SONET Copper Wireless Security can be applied in all layers as appropriate “DWDM”: Dense Wave Division Multiplexing “SONET”: Synchronous Optical NET

  13. The IP Protocol Stack OSI Stack Application • Layer 4-7 (TCP, UDP, RTP etc) • Layer 3 Network Layer (today IP) • IP addressing (e.g. 192.168.1.1) • Basic delivery (no guarantees) • Layer 2 Link layer (Ethernet MAC, HDLC) • Packet delineation • Variable time delay, error free • Optional QoS, flow control and error recovery • Link Layer addresses • Layer 1 Physical Layer (copper, fibre, wireless) • Transmission of a serial bit stream • Dedicated path between two entities • Shared path among multiple parties (e.g. wireless) Presentation Session Transport Network Link Physical “TCP”: Transmission Control Protocol “UDP”: User Datagram Protocol “RTP”: Real-Time Protocol “MAC”: Media Access Control “HDLC”: High Level Data Link Control

  14. Switch/ Router Queuing and Packet Switching output inputs 10 5 • Queuing introduces variable delays • Congestion control required to protect the network • Quality of Service (QoS) mechanisms available for time critical traffic Total time Service time utilization 100%

  15. Application Server Routing Challenges in Packet Networks Switch/ Router “C” Switch/ Router “A” Switch/ Router “E” Switch/ Router “B” Switch/ Router “D” • Links can have • Different speeds • Different utilizations • Different delays • Different operational states (up or down) Routing system has two objectives: • Maximize network utilization and minimize routing convergence times • Meet user/application needs

  16. Application Server Routing Options Switch/ Router “C” Switch/ Router “A” Switch/ Router “E” <<RP>> <<RP>> <<RP>> <<RP>> Switch/ Router “B” Switch/ Router “D” Routing Protocol exchanges routing information periodically <<RP>> Routing Table is maintained and specifies what is “best” link to take for each destination • Flat vs hierarchical (for scalability) • Static vs dynamic routing • Distance Vector (e.g. hop count to each destination) vs Link State Routing (each node has network view) • Per packet vs per flow • Added requirements • Load balancing • Policy-based routing • ‘Cost’ of links

  17. The Standard Layer 3… IPv4 OSI Stack Application Presentation • Defined in 1983 along with TCP • Connectionless networking • Non-sequence preserving and lossy (End-to-end TCP is sequence preserving and lossless) • 4 Byte IP address per packet • 20- 65,535 Bytes in length (but, generally, Ethernet has max of 1522 Bytes) • Full suite of networking protocols • Routing protocols • Multicast • QoS and traffic management • IPv6 is starting to be deployed! • First Asia, public wireless and defence networks Session Transport Network Link Physical

  18. IPv6 • Defined in 1999 • Greatly expanded address space (vs 4.3B addresses defined in IPv4) • Historical imbalance in distribution of IPv4 addresses • North America vs Asia • Early-adoptor large corporations got huge address spaces • 2B Internet users worldwide and growing • Internet of Things explosion • Network and end device implications • Can co-exist with IP v4 networking Next generation IP address standard intended to supplement and eventually replace IPv4

  19. Trailer (Layer 2): 2-4B CRC Layer 4 RTP: 12B including timestamps (for voice); more for data UDP: 8B including source/destination port addresses TCP: 20B including port addresses, sequence numbers and window controls; connection setup requires 3-way handshake IP: 20B (40B for IPv6) including two addresses Ethernet: 18 B (bytes) IPv4-on-Ethernet Protocol Stack Packet Formats HDLC Trailer Layer 2 Header Level 3 Header Level 4-7 Headers Data (0-1500B) Flag Flag “CRC”: Cyclical Redundancy Check

  20. Packet Switching Performance Parameters • Transit delay: time from transmission to reception • Access link delay (queuing time, emission time, propagation time) • Network transit delay ( access + switch + trunk delay) • Average vs distribution of delays • Throughput • Switch • Trunk • Access • User application • Measures of efficiency • Processor and trunk utilization • % overhead for payload • Challenges • Traffic characterization (driver behaviour and prioritization) • Protecting the network (maximizing cars/minute) Networking objectives (just like the 417) • Maximize network utilization • Meet user/application needs

  21. Outline • Packet technology • The enterprise perspective • Concluding remarks

  22. Traffic Threats Time Applications The CIO’s dilemma IT Budget Time The Enterprise Perspective Business IT needs: • To do more with less • To drive employee productivity wherever they are • To use IT to grow revenues • To use IT to anticipate customer requirements Large corporations want to leverage carrier IP and non-IP services, with best bang for the buck, control, security and reliability.

  23. Large Business and Government Organizations…. • Have very large internal IP networks (often with private IP addresses) • Are reluctant to expose their internal traffic to Internet insecurity etc • Have economic access to raw bandwidth • Can suffer large economic loss from network and security failures • Need management control to respond to internal business owners and their customers

  24. Example of Large Campus Network • 5000 employees • 10,000 10/100 and 10/100/1000 Mbps ports to desktops and servers • Resilient Ethernet switches in 50 wiring closets (<100m to each desk) • 12 redundant Ethernet Routing switches in backbone • Hundreds of WLAN Access Points • >100 Gbps uplink capacity and >Tbps switching capacity • Layered security • Centralized control Applications: Hundreds of business apps, Collaboration, Social networking,Email, Instant Messaging, Video and Audio Streaming

  25. Wireless Ethernet (802.11) Cell “B” Cell “A” Ethernet Switch Workstation Ethernet Segment (10BaseT or 10/100 autosense) Access Point Access Point Powered Over Ethernet • Multiple standard modes: 3 channels @11Mbps; 3 channels @54Mbps; 10+ channels @54 Mbps; 13 channels @100Mbps • Low power unlicensed operation over limited distances (<100m indoors)

  26. Mobile user Database Application Server Network View WLAN & cellular DSL Cable modem Ethernet Branches & remote sites Larger sites Data centres ? Customer or Telecommuter The Internet WAN VPN Router LARGE CAMPUS Campus core/distribution Aggregation/Access Edge (Wiring Closet) Campus backbone Ethernet Routing Switches Ethernet Switches WLAN Laptop “VPN”: Virtual Private Network “DSL”: Digital Subscriber Line

  27. Enterprise Inter-Site Connectivity Options Campus networks Branch networks Regional center Data centres HQ Branch Remote office Many Layer 1 options • Private lines • Dark fibre • Fibre rings with DWDM • SONET rings Layer 2 Packet Services • Ethernet connectivity Layer 3 VPNs • MPLS and/or IPSec over public IP Business Apps & Storage Service providers developed ‘Layer 2’ packet services: • Ethernet services • Multiprotocol Label Switching (MPLS)

  28. Connection-oriented MPLS Networking D E A • IP-based Connections • IP control plane for topology and addressing • Switching based on connection-ids (MPLS labels) • Enterprise site-site IP can run over these connections • Segregation from public Internet • Handling of private enterprise IP addressing • Improved security and control • Economics of packet for enterprise connectivity MPLS connections C B

  29. Outline • Packet technology • The enterprise perspective • Concluding remarks

  30. Let’s End With A Reality Check • Everything on IP and IP on everything • Simplification via bandwidth • Access to wired core network is split across multiple technologies • Ethernet for desktops • DSL, cable and some fiber to homes • WiFi for mobile hotspots • 2-4 and emerging 5G public wireless • Carrier MPLS backbones for improved public Internet operations and enterprise VPNs • Ethernet MANs for high speed Layer 2 connectivity

  31. What’s Hot in Packet Switching? • Making IP networks more scaleable and improving economics • Economic expansion of IP for telephony in carrier networks • Explosion in broadband wireless including 802.11n • Beyond 10 Gbps Ethernet (40 or 100?) • Terabit switch routers (hardware/hardware/hardware) • Increased end-to-end throughputs • Evolution/transition to IPv6 • Security everywhere • Expanding application fit of IP networking • Internet of Things • 4 and 5G Internet-optimized public wireless • More IPTV • Storage on IP • More gaming Debate: pure Layer 3 vs application-fluent network intelligence Lots of Opportunities for You!

  32. A Parting Thought Technology is not an end in itself! It has to take you where the user wants to go

  33. For More Information On packet switching http://en.wikipedia.org/wiki/Packet_switching “Commercialization of packet switching (1975-1985): A Canadian perspective” by T.Rybczynski On all things IP http://www.ietf.org/ On all things wired and wireless Ethernet http://www.ieee802.org/ + Course lectures on: MPLS, VoIP, Internet of Things, WiFi and Internet Technology Bon Voyage and Thank You

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