The Story of ChronoShare, or How NDN Brought Distributed File Sharing Back Alex Afanasyev, Zhenkai Zhu, Yingdi Yu, Lijing Wang, Yukai Tu, Lixia Zhang UCLA

File sharing is in great demand today Multiple solutions exist today, with different synchronization models Centralized control simple implementation single point of failure Impact on network load, performance Peer-to-peer remove single point of failure Mismatch between apps and network Mismatch between p2p connectivity and underlying topology

ChronoShare: Enabling File Sharing in Truly Distributed Way Name-based rendezvous Data-centric security provenance, integrity, group-access control Keeping local communication local Efficient data sharing Multiple parallel downloading Supporting device mobility and intermittent connectivity

ChronoShare: components

ChronoSync as a Distributed Transport Function files, actions knowledge about actions Z. Zhu and A. Afanasyev, "Let's ChronoSync: Decentralized Dataset State Synchronization in Named Data Networking," in Proceedings of the 21st IEEE International Conference on Network Protocols (ICNP 2013), Goettingen, Germany, October 2013.

ChronoSync Digest Tree Progress /Alice/1 UPDATE /a.jpg to v=1 0x0000... 0xabc1... 0x331a... 0xbbaa... 0xccaa... 0xbbad... 0x112a... /Bob/1 UPDATE /a.jpg to v=2 /Alice/1 /Alice/2 /Alice/3 /Bob/2 /Bob/1 /Dave/2 /Dave/1 /Dave/1 UPDATE /a.jpg to v=3 /Bob/2 UPDATE /a.jpg to v=4 /Dave/2 /Alice/1 /Bob/1 /Dave/1 /Alice/2 UPDATE /z/b.txt to v=1 /Alice/2 /Bob/2 /Dave/2 /Alice/3 /Alice/3 DELETE /z/b.txt

ChronoShare: Recent Progress Polished up implementation, ready to use (pointer to the release below) With NDN CC’s support for ad hoc WiFi: direct file sharing one doesn’t have to change to different mode of operation based on distance or device types /Alice /Bob https://named-data.net/codebase/applications/chronoshare/ /Dave

Take Away NDN with the use of ChronoSync-based ChronoShare brings back truly distributed and secure file sharing name-based multicast, mobile, and DTN-style data retrieval name-based rendezvous name-based communication scoping data-oriented security Basic system picture User/device names are in general location-independent If a name prefix is in FIB, it is reachable, otherwise its location prefix should be in FIB LINK object to reach one the users The focus is on getting desired data, instead of tracking device status or locations Find device location prefix on a “need to know” basis A device can report its current location prefix How it works: focus on file, not device SYNC Interest brings back action data (=action+file name), Use file-name to fetch, if no reply, send to broadcast channel, asking “who has this file?” Whoever has the file replies with its location-prefix Handle device disconnect by fetching from cached copies

Thanks Questions? Email: aa@cs.ucla.edu

ChronoShare: Recent Progress Interest( <device> , <shared-folder> , <action-seq> ) Interest( <device> , <file-hash> , <segment> ) Data( <file> , <action> ) Data( <file>) /Alice /Bob /Dave