IPv6 and OverlaysIPv6: MotivationPacket FormatLarger address is not everythingComparison of IPv4 and IPv6Limitation of IP layer servicesInternet TodayGoalsOne SolutionExampleResilient Overlay Network (RON)What about P2P networks?IPv6 and OverlaysEE122Introduction to Communication NetworksDiscussion Section2IPv6: MotivationNeed for a larger address space-Explosive growth-Under-utilization by class A/B/C addresses- MinusCIDR, NAT increase usable address space+ PlusWireless sensor networks, ubiquitous computing require small devices have IP addresses3Packet FormatFrom wikipedia4Larger address is not everythingHeaders structure is made to improve the performance of routing (from wikipedia)No fragmentation-PMTU discovery is neededNo checksumFlow label – QoS managementIPsecMulticast5Comparison of IPv4 and IPv6IPv4 IPv6Address Size 32 bits 128 bitsFragmentation Supported Not supportedChecksum Yes NoQoS No YesIPsec No YesMulticast No Yes6Limitation of IP layer servicesQoS-Payment issueIPsec-End-to-End argumentMulticast7Internet TodayChanges in the network happen very slowly-IPv6 not deployed widely yet-Other examples: IPSEC (93), IP Multicast (90)Why?-Internet network is a shared infrastructure; need to achieve consensus (IETF)-Many of proposals require to change a large number of routers (e.g., IP Multicast, QoS); otherwise end-users won’t benefit -One size does not fit all•Different applications have different requirements8GoalsMake it easy to deploy new functionalities in the network accelerate the pace of innovation Allow users to customize their service9One SolutionDeploy processing in the networkHave packets processed as they traverse the networkAS-1IPAS-1Overlay Network(over IP)10ExampleDefault IP path determined by BGP & OSPFReroute traffic using red alternative overlay network path, avoid congestion pointActs as overlay routerBerkeleyMITUCLA11Resilient Overlay Network (RON)Premise: by building application overlay network, can increase performance and reliability of routing Install N computers at different Internet locationsEach computer acts as an overlay network router-Between each overlay router is an IP tunnel (logical link)-Logical overlay topology is all-to-all (N^2)Computers actively measure each logical link in real time for-Packet loss rate, latency, throughput, etcRoute overlay network traffic based on measured characteristics12What about P2P networks?Some overlays are p2p networksSome p2p networks are
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