1. DHT-Oriented Architecture: A Prototype Maxwell Krohn, Jeremy Stribling, Michael Walfish jmm@pdos.lcs.mit.edu MIT 6.824 Project Demonstration 29 April 2004

2. Old Goal: Separate Location and Identity  An IP address conflates: –Network location –Identity, sort of  So?  Well, that means: 1)Mobility, multihoming, renumbering awkward 2)Tough to reach hosts behind NATs Subject of Demo

3. Recent Proposal: DOA  Hosts get flat identifiers (EIDs) Packet Format  Transport connection bound to EID pair  IP addr gives only routing information IP Header SRC EID DST EID Transport Header (TCP or UDP) Body EID: iuv8h… IP: 18.26.4.245 EID: gbyjgx… IP: 66.59.66.4 TCP Host 1 Host 2

4. Recent Proposal: DOA, cont’d  EIDs passed out of band; map to an IP addr  Assume a mapping service in the sky: IP Header SRC EID DST EID Transport Header (TCP or UDP) Body EIDIP Address 8iabv2hmbsipse49qertgb5muury79tk 66.59.66.4 gbyjgxf6pkninur7jirpzjc3ftwpvfpd 18.26.4.245 iuv8h9r7qxycwkfh4whcsd3ufw4acp6i 18.26.4.245

5. DH T LOOKUP DOA in a Nutshell Problem: identifiers are flat! How to map them to actual IP addresses? User App EID-to-IP Mapping IPEIDTCP Internet Network Stack sendto(EID) Claim: DOA addresses NAT difficulties Host Pkt

6. Reaching NATed Hosts in DOA  EIDs of NATed hosts map to NAT’s IP  NATs use the host identifier, EID, to demux  Many servers behind NAT on same TCP port EID  local IP iuv8h9r7qxyc 192.168.0.10 8iabv2hmbsip 192.168.0.11 NAT ( 18.26.4.245 ) IP: 18.26.4.245 EID: iuv8h PRT: 22 Host 1 Host 2 Packet

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8. DH T Demo of DOA Prototype Client NAT 1NAT 2 Host 1 Host 2 (18.26.4.245) iuv8h … 8iabv… > ssh iuv8h9r7q.DOA

9. Conclusion DOA: 1)permits the location/identity split, which: –supports multi-homed hosts (not discussed) –accommodates hosts behind NATs 2)uses a DHT to map flat EIDs  IP addrs 3)has no chance of ever being deployed