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Capsule-based Active Networks: What have we learned?. David Wetherall (djw@cs.washington.edu) University of Washington. State of Active Networks. AS1. ACTIVE IP. Plugins. Softnet. ANTS. ??. M Ø. PLAN. The Active Internet. PAN. Vision. 96. 97. 98. 99. 00. …. 0x.
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Capsule-based Active Networks: What have we learned? David Wetherall (djw@cs.washington.edu) University of Washington
State of Active Networks AS1 ACTIVE IP Plugins Softnet ANTS ?? MØ PLAN The Active Internet PAN Vision 96 97 98 99 00 … 0x Are we there yet? So when can I use it? djw // OpenSig’99 // 10/99
Context: Styles of Extensibility Getting beyond “One size fits all” djw // OpenSig’99 // 10/99
This is ANTS • Aim: Each user controls the handling of their own packets in the network • How well does this work? capsules User 1 User 2 active nodes djw // OpenSig’99 // 10/99
ICMP as a Minimal System • ICMP • Runs at all IP routers, can be used by all users • Programs • Traceroute, path MTU discovery performance security flexibility ICMP ANTS? djw // OpenSig’99 // 10/99
ANTS Tradeoffs • Mobile code for flexibility • Simple forwarding model for performance / security • Depend on caching; target experimentation #7 IP #7 data RUNTIME #23 djw // OpenSig’99 // 10/99
Accepting Heterogeneity • Can’t make forwarding simpler, so processing ultimately depends on node’s abilities /position • E.g. 1GHz, 1Gbps, 1000b, 100% 1000 cycles • Or if 100Mbps, 10% 100,000 cycles • Wide variation heterogeneity is fundamental • Build into programming model • Can query node to determine what’s appropriate • Non-active nodes (IP routers) at bottom djw // OpenSig’99 // 10/99
A Minor Matter of Security • Vision: unprivileged users have unrestricted access • Requires Protection • My program can’t corrupt your program We know how to do this • Requires Resource Management • My program can’t starve your program The harder problem djw // OpenSig’99 // 10/99
Resource Management Tasks djw // OpenSig’99 // 10/99
The “Per Packet” Problem • TTLs are a weak solution; not related to topology • Fairness mechanisms mitigate, but arguably not enough • Restricted program forms may help … Want to Stop this! djw // OpenSig’99 // 10/99
Programming with ANTS • Examples • Multicast (single source and PIM) • Mobility • Reliable Multicast support • Path MTU discovery • Auctions • Web cache diversion routing • “TCP-SYN” filtering djw // OpenSig’99 // 10/99
Lessons / Discoveries • How to program mixed networks: A complication • Code as flexible “glue”: Many variations • A clean way to query the network: Heterogeneity • The set of unchangeable things: Shared assumptions More Application Experience is Needed! djw // OpenSig’99 // 10/99
More Details • See paper in SOSP’99: • Active Network Vision and Reality: Lessons from a Capsule-based System, D. Wetherall. djw // OpenSig’99 // 10/99