1. Network Support for Accountability Nick Feamster Georgia Tech Collaborative Response with David Andersen (CMU), Hari Balakrishnan (MIT), Scott Shenker (UC Berkeley/ICSI) Georgia Tech Response with Wenke Lee and Mustaque Ahamad

2. 2 Two Responses (Double Duty) Towards an Accountable Internet Architecture, Andersen, Balakrishnan, Feamster, Shenker In-Band, Bottom-Up Support for Availability and Accountability, Feamster, Lee, Ahamad

3. 3 Internet Accountability Mechanisms to identify, isolate, punish bad behavior Distinct from accounting (cf. original Clark design goals) What is it? Why might the network need to support it? Attacks on the routing system Control over traffic Tracking and mitigating malice –Spam –Botnets –Phishing

4. 4 Facets of Internet Accountability Source: defense against address forgery Data-plane: identify faulty network elements Control-plane: identify forged routing messages Recourse to avoid faulty or malicious elements –Scalable network support for path diversity –Better mechanisms to curtail unwanted traffic

5. 5 AIP: Accountable IP Refactoring of Internet addresses: AD:EID –AD: The autonomous domain of the host –EID: A globally unique endpoint identifier Addresses are self-certifying Why change addressing? –Forms the cornerstone of routing, forwarding, identity –Current address structure makes existing mechanisms clumsy –New structure retains simplicity at the network layer and above ADEID Hash of autonomous domains public key Globally valid endpoint identifier (cf. IPv6 CGA, HIP, etc.)

6. 6 Source Accountability Problem: Sources can forge IP addresses –Can complete three-way handshakes (LAN spoofing) Why it matters: Complicates filtering, blacklisting. –Spam campaigns regularly have 70% fresh IP addresses Solution: Self-certification + Challenge/Response

7. 7 Control-Plane Accountability Problem: Routing messages can be forged Why it matters: –Misconfiguration: AS 7007, ConEdison route leak –Malice: Spammers stealing address space Solution: S-BGP-style attestations + self-cert –Interdomain routing and forwarding is on Ads –The AD is the public key and the address –Eliminates the need for a mapping between IP address space and organizations

8. 8 Data-Plane Accountability Problem: Network elements drop packets, fail, and otherwise give rise to poor performance One Solution: In-Band Path Diagnosis Routers keep track of number of packets seen per flow Each router stamps each packet with current flow counter value If current counter value does not equal routers expected packet count for that flow, router marks packet IP Header New Shim Header Transport header Method Overview

9. 9 Cornerstone Projects In-Progress –Control-Plane: Implementation of control plane accountability (XORP) –Data-Plane: Implementation of in-band diagnosis (XORP/Quagga on VINI) Imminent –Coping: Multiple ongoing efforts Architectural mechanisms for supporting path choice Scalable route diversity protocol that uses network virtualization (analysis, implementation on VINI)