VoCCN: Voice over Content-Centric Networks Van Jacobson, Diana Smetters, Nick Briggs, Michael Plass, Paul Stewart, Jim Thornton, Rebecca Braynard Palo Alto Research Center (PARC) ReArch ’09 1 December 2009 Rome, Italy
Everybody knows that ... • Content-based networking is great for content dissemination ... • ... but can’t handle conversational or real-time traffic. ‘Everybody’ is half right. 2
Content networking is more general than IP It does anything that IP can. To demonstrate this we implemented VoCCN, a VoIP-functional-equivalent based on CCN. (The way we map the IP conversation model isn’t CCN-specific and should work for other Pub/Sub systems.) 3
VoCCN – why bother? • VoIP works badly for multi-point, multi-interface and mobility. • VoIP security is poor. • VoIP setup is complex. ENUM + NAPTR + SRV a.com b.com SIP proxy SIP proxy INVITE sips:bob@b.com M M S S sip:bob@b.com sip:bob@b.com INVITE INVITE STUN/UPnP STUN/UPnP IP IP Alice Bob 4
IP builds conversations using two patterns: B-IP A-IP SIP port 12345 A B • Service to instance data B-IP:SIP/ SIP service SIP client • Uni- to bi-directional SIP B-IP:SIP/A-IP:12345 instance A-IP B-IP A-IP:12345/B-IP:SIP 12345 SIP port data These are just ‘name’ manipulations that should map to any (topic-based) pub-sub system with hierarchical or algorithmic names. 5
VoCCN has only a few moving parts C C ? b.com/sip/bob/invite/E pkB (sk) /E sk (invite) C C REG: b.com/sip/bob C C IP IP Alice Bob • Resulting system is simple, secure and scalable. • Robust support for mobility and multi-point. • Supports secure, stateless, VoIP inter-operation. 6
Performance Packet Interarrival Times 1 70 Link A traffic 0.9 Link B traffic 60 link A link B link A disconnected disconnected disconnected 0.8 CDF: Proportion of Packets 50 0.7 Rate (pkts/sec) 0.6 40 0.5 30 0.4 0.3 20 0.2 10 0.1 Stock LinPhone CCN LinPhone (encrypted) 0 0 0 10 20 30 40 50 60 70 80 90 100 0 20 40 60 80 100 120 140 160 180 Packet Interarrival Time (ms) Time (sec) from Start of Call 7
Availability • Our (open-source, GPL’d) CCN stack is available at www.ccnx.org . • The VoCCN linphone code should be there by the end of this week. Questions? 8
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Message exchanges Caller (Alice) Callee (Bob) <registers a desire to see interests asking for content beginning with / domain /sip/ bob /invite> "#$%&'#%$!(&)*! Interest: ! / domain /sip/ bob /invite/ E pkB (sk) / E sk ( SIP INVITE message) Data: ! Name: !!!!!!!! / domain /sip/ bob /invite/ E pkB (sk) / E sk ( SIP INVITE message) Signature Info: <metadata>, <signature> Content: E sk ( SIP response message ) Interest: ! / domain / bob / call-id /rtp/ seq-no Data: ! Name: !!!!!!!!!!!!!!!!!!!!!!!!! / domain / bob / call-id /rtp/ seq-no +,-#&!(&)*! Signature Info: <metadata>, <signature> Content: SRTP packet (encrypted audio) Interest: ! / domain / alice / call-id /rtp/ seq-no Data: ! Name: !!!!!!!!!!!!!!!!!!!!!!!!! / domain / alice / call-id /rtp/ seq-no Signature Info: <metadata>, <signature> Content: SRTP packet (encrypted audio) 10
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