Packet Switching: LAN to WAN Wired to Wireless Consumer to Enterprise Notes Tony Rybczynski Tonyryb@rogers.com

Life Senior Member of IEEE 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

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

Packet Switching in 3 Parts Part 1: The basic technology Part 2: The enterprise perspective Part 3: Not just connectionless packet

Part 1: Circuit Switching (TDM) vs Packet Switching 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 56Kbps 56Kbps TDM Switch TDM on SONET TDM Switch Mux / Demux Mux / Demux 10/100/1000Gbps 56Kbps, T1, T3 IP/fibre Router Router Packet Switching is a much more flexible and evolvable technology

Packet Switching: A General Definition Message or bit stream subdivided into packets Individually addressed packets Dynamic bandwidth Access and trunk multiplexing Traffic bursts at full pipe capacity Layered operation Application protocols above Transmission facilities/pipes below Seven Layer OSI model helps- packet switching applied at Layer 2 and 3 Exploitation of 'bursty' nature and tolerance to delays of most applications Functionality: routing, flow control, error control, Quality of Service (QoS) … “OSI”: Open System Interconnection

Packet Switching Time Line Ethernet (’80) Token ring et al TCP/IP (’83) Academic Internet Research Nets for robust data comm Voice and video Over IP Mobility ARPAnet (‘72) Commercial X25 nets (‘76) 4G wireless Gaming IPTV Storage/IP Commercial Internet (’94) Frame relay/ATM 1960s 1970s 1980s 1990s 2000’s Present

Many Faces of Packet Switching A set of technologies Switching & multiplexing architecture Packet formats Connectionless or connection-oriented paradigms Transportable on different media at varying speeds LAN/MAN/WAN/wireless networks A carrier service capability Basis for tarriffed services Unicast and multicast A set of open standards Interface and networking standards User and network interface protocols Service definitions Performance metrics Security Adaptation and encapsulation standards “LAN/MAN/WAN”: Local/Metro/Wide Area Net

Scope of This Lecture Layer 4-7 (TCP, UDP, RTP etc) Layer 3 Network Layer (today IP) IP addressing (e.g. 192.168.1.1) Basic delivery with QoS optional Layer 2 Link layer (Ethernet MAC, HDLC) Packet delineation Variable time delay, error free Optional QoS, flow control and error recovery Link addresses (e.g. MAC address: 0007E08CBB04) Layer 1 Physical Layer (copper, fibre, wireless) Transmission of a serial bit stream Dedicated path between two parties Shared path among multiple parties (e.g. wireless) OSI Stack Application 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

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

The Standard Layer 3… IPv4 Origins >30 years ago (ARPAnet) Connectionless/”datagram” networking (not sequence preserving, lossy) 4 Byte IP address per packet Full suite of networking protocols Routing protocols (e.g. RIP- Routing IP, OSPF- Open Shortest Path First) Multicast (e.g. IGMP- Internet Group Membership Protocol, DVMRP- Distance Vector Multicast Routing Protocol, MOSPF- Multicast OSPF, PIM- Protocol Independent Multicast) QoS and traffic management (RSVP- Resource reSerVation Protocol) IPv6 is starting to be deployed! First Asia, public wireless and DoD Required for address scalability (16 B addresses) and increased security (IPsec) OSI Stack Application Presentation Session Transport Network Link Physical “FTP”: File Transfer Protocol

Example: Packet Formats Layer 2 Header Level 3 Header Level 4-7 Headers Data (0-1500B) HDLC Trailer Flag Flag IP: 20B (40B for IPv6) including two addresses Ethernet: 18 B (bytes) Point to Point PPP: 5B including opening sequence UDP: 8B including source/destination port addresses TCP: 20B including port addresses, sequence numbers and window controls; connection setup requires 3-way handshake Layer 4 RTP: 12B including timestamps (for voice); more for data Trailer (Layer 2): 2-4B CRC “CRC”: Cyclical Redundancy Check

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

Routing Challenges in Packet Networks Switch/ Router “C” Switch/ Router “A” Switch/ Router “E” Application Server 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

Routing Options Flat vs hierarchical (for scalability) Switch/ Router “C” Switch/ Router “A” Switch/ Router “E” Application Server <<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

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 (just like highway 417) Traffic characterization (driver behaviour and prioritization) Protecting the network (maximizing cars/minute) Networking objectives: Maximize network utilization Meet user/application needs

Packet Switching: Advantages/Disadvantages Bandwidth only consumed when needed Reduced cost of bandwidth Reduced cost sensitivity to distance Speed conversion 56Kbps modem access to 100GigE server Dynamic routing Connection Connectionless Leveraging of end point processing Flow and error control But ... Processing requirements per packet Complexity Routing algorithms Congestion control Protocols Variable delays

Part 2: 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 Time Traffic Applications IT Budget The CIO’s dilemma Threats Message: Here’s a high level opener to initiate dialog with the customer on his/her priorities and challenges. We focus on CIO’s environment to make you successful. Large corporations want to leverage carrier IP and non-IP services, with best bang for the buck, control, security and reliability.

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

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

High-performance level maintained in case of a switch failure Ethernet Switching to the Desktop Dedicated bandwidth to each desktop Standard Carrier Sense Multiple Access (CSMA)/ Collision Detection 100 meter wired range Flat MAC addressing space Power over Ethernet (for VoIP, WLANs, security devices) Standard QoS 10/100/1000 Gbps Over Category 5 wiring High-performance level is maintained even in case of a failure. If a cable is disconnected, the performance drops only by 80 Gbps. The total stack bandwidth in this case is 640-80 = 580 Gbps (88% of 640 Gbps). If a switch were to fail, the performance may drop by 160 Gbps. The total stack bandwidth in this case will be 640-160 = 480 Gbps (75% of 640 Gbps) With traditional ring architecture design, the performance may drop by 50%. But with FAST design, the performance is maintained at a high bandwidth. This diagram also shows the fail-safe stacking feature. If a switch were to fail in a stack, all the other switches in the stack continue to function as a stack. For fail-safe stacking, the cascade return cable must be connected (as shown in the diagram). High-performance level maintained in case of a switch failure

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)

Ethernet Routing Switches Network View Mobile user 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 Database Application Server WLAN Laptop “VPN”: Virtual Private Network “DSL”: Digital Subscriber Line “3G CDMA/GSM”: third gen public wireless 3

Enterprise Inter-Site Connectivity Options Campus networks Regional center Branch networks 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 Messages: Nortel is the #2 in the data space. Nortel offers both best in class solutions for multivendor networks and is the only one of two vendors who can offer comprehensive end-to-end converged networking and security solutions On the diagram: The boxed areas identify solutions areas that can be targeted with Nortel products in a multivendor environment. The functionality in the cloud is offered by Nortel as part of an end-end solutions. Service providers developed ‘Layer 2’ packet services: Ethernet services Multiprotocol Label Switching (MPLS)

Part 3: Not Just Connectionless IP Packet Switching & Multiplexing Packet Switching Statistical Multiplexing Circuit Switching TDM Multiplexing Connection- Oriented Connectionless Layer 3 IP Layer 2.5 MPLS Layer 2 Frame Relay/ATM Layer 2 Ethernet Copper/fibre MAN/WAN Wired MAN Wireless LAN/MAN Carriers developed connection-oriented & connectionless ‘Layer 2’ packet services to meet enterprise needs MPLS was also developed as carrier backbone technologies for enhanced traffic management capabilities

Connection-oriented Packet Nailed up connections C B Connections could be frame (Frame Relay) or IP-based (e.g. MPLS) Switching based on connection-ids (MPLS labels) Enterprise site-site IP runs over these connections Segregation from public Internet Handling of private enterprise IP addressing Improved security and control Economics of packet for enterprise connectivity

MultiProtocol Label Switching (MPLS) MPLS allowed carriers to meet enterprise needs, AND to address traffic management challenges in their public IP networks Connectionless IP Connection-oriented packet MPLS IP routing software IP routing software Connection control plane Label Swapping Label swapping Forwarding IP control plane for topology and addressing QoS defined for transport of IP traffic Label swapping paradigm for VPNs & traffic management

Let’s End With A Reality Check Everything on IP and IP on everything Simplification via bandwidth Access is split across multiple technologies Ethernet for desktops (may be displaced by WiFi) WiFi for mobile hotspots DSL, cable and some fiber to homes 2-4G public wireless Carrier backbones evolving to Ethernet MANs and MPLS WANs for public Internet and enterprise VPNs

What’s Hot in Packet Switching? Making IP networks more scaleable and improving economics Explosion in broadband wireless including 802.11n Beyond 10 Gbps Ethernet (40 or 100?) Terabit switch routers (hardware/hardware/hardware) Evolution/transition to IPv6 for end-to-end addressing scalability Security everywhere Expanding application fit of IP networking Sensors 4G Internet-optimized public wireless IPTV Storage on IP More gaming Debate: application-fluent network intelligence Lots of Opportunities for You!

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

For More Information Bon Voyage and Thank You 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.ieee.org/web/standards/home/index.html + Course lectures on: VoIP, Internet of Things, WiFi, Internet Technology and Large-scale IP Network Design Bon Voyage and Thank You