Review of the literature : VoCCN: Voice-over Content-Centric Networks Takashima Daiki Waseda University, Japan 1/13

Outline 1. Introduction 2. VoIP background 3. VoCCN architecture -VoCCN/VoIP Interoperability 4. Simulation 5. Conclusion 2/13

Introduction Fact: There is widespread agreement that content should have a more central role in future network architectures than the Internet’s current host-to-host conversation model. Goal: To investigate Voice Over CCN – a real-time, conversational, telephony application over Content-Centric Networking (CCN). Doubt: How well the idea fits more conversational traffic such as , e-commerce transactions or VoIP? 3/13 phone call Figure 1: Use case of Voice-over-IP

Background (1) ~VoIP~ Voice over Internet Protocol (VoIP) is dominant open protocol for Internet telephony. When making a phone call, VoIP phones set up a signaling path by using the Session Initiation Protocol (SIP). 4/13 As VoIP endpoints are often mobile, signaling path exchanges are mediated by VoIP that receive and forward messages on behalf of their client endpoints. Figure 2: Voice-over-IP data flows.

Background (2) ~SIP~ 5/13 Figure 3: Sequence diagram of SIP INVITE message. INVITE SIP/2.0 Via: SIP/2.0/CCN parc.com:5060 From: Alice Briggs To: Bob Jacobs Call-ID: CSeq: 20 INVITE Content-Type: application/sdp Max-Forwards: 70 User-Agent: Linphone/3.0.0 (eXosip2/3.1.0) Subject: Phone call Expires: 120 Content-Length: 1477 [... o=alice IN IP c=IN IP a=key-mgmt: mikey AQQFgE3dV+ACAA... m=audio 7078 RTP/AVP ] Figure 4: Example of SIP INVITE message. ① INVITE ② INVITE ④ INVITE ③ 100 Trying ⑤ 100 Trying ⑥ 180 Ringing ⑦ 180 Ringing ⑧ 180 Ringing ⑨ 200 OK ⑩ 200 OK ⑪ 200 OK ⑫ ACK (session-establishment is accepted) Session is established (conversation is done) ⑬ BYE(session disconnect request) ⑭ 200 OK (session disconnect) Alice ccnx.org proxy parc.com proxy Bob

Background (3) ~Mismatch in VoIP~ VoIP Signaling and Media paths result from a mismatch between the user’s goal and the network’s meaning of achieving it. Alice simply wants to talk to Bob but the network requires that the communication be addressed to the IP address of Bob’s phone. 6/13 One strong point of content-oriented networking is that this translation (typically referred to as middleware) is not needed. Figure 2: Voice-over-IP data flows.

VoCCN architecture (1) 7/13 Figure 5: Voice-over-CCN data flows. A caller maps a SIP INVITE into an Interest packet asking for new content from callee, which generates a piece of Data with the requested name containing the SIP response, thus completing SIP signaling in a single round trip. Challenges: ・ Support service rendezvous: request a connection and get a confirmation response. ・ On-demand publishing is needed: request data that was not published yet. ・ Transition phase: from rendezvous to a bi-directional conversation.

Inline message security: ・ Caller: encrypt and authenticate SIP invite using random-Inline message encriptation generated symmetric key (sk) ・ Caller: encrypt sk using callee’s public key (pk B) ・ Callee: decrypt interest using his/her private key ・ Callee: uses sk to verify and decrypt SIP invite message VoCCN architecture (2) 8/13 Figure 6: Protocol exchange. Componets of Interest

VoCCN/VoIP Interoperability The VoCCN/VoIP proxy serves as the SIP proxy for external inbound VoIP calls, and translates from VoIP packets (SIP and SRTP) to VoCCN packets and vice versa. 9/13 The proxy then performs the CCN-specific parts of the call on behalf of the VoIP client – generating and sending an Interest in the next packet of the exchange. The proxy examines a VoIP packet and generates a corresponding CCN packet whose name is determined based on information in the original inbound packet header. Fig 7.VoCCN/VoIP Interoperability VoIP VoCCN Media Path Signaling and Media Path Signaling Path VoIP-VoCCN gateway

To evaluate CCN’s ability to support timely delivery or realtime data the authors looked at the packet arrival times for their VoCCN implementation. 10/13 ・ Proof-of-concept of real-time CCN ・ Extension of Linux VoIP phone (libeXoSIP, liboRTP) ・ Open CCN toolkit (CCNx): routers run on endpoints. ・ Support multi-point routing (mobility) ・ Easy to build advanced services (e.g. conference calls) Simulation (1)

Simulation (2) 11/13 LinPhone Packet Interarrival Time Packet interarrival Time (ms) CDF: Proportion of Packets CCN LinPhone - Encrypted Stock LinPhone The VoCCN call has slightly fewer packet. With almost equal delivery performance, VoCCN and VoIP have same call quality. Figure 4: Cumulative distribution of inter-packet intervals, or jitter, for a 10-minute voice call. Limitations/Open Issues ・ Constructable names: flexibility may require partial names that are not unique ・ Pipeline of Interest packets: not proved to perform Performance for a 10 minutes conversation: ・ More packets below the expected inter-packet interval ・ Small number of long-interval packets ・ No packets loss for both cases

12/13 ・ CCN can not only move content scalably and e ffi ciently, they can also implement IP-like conversational services like voice calls, or transactions. ・ Voice-over-CCN is functionally and performance equivalent to Voice-over-IP. ・ It is more simpler in architecture, implementation and configuration. ・ VoCCN is completely interoperable with VoIP via simple, stateless gateways. Conclusion

[1] V.Jacobson, D. K. Smetters, N. H. Briggs, M. F. Plass, P. Stewart, J. D. Thornton, and R. L. Braynard, “VoCCN: Voice-over Content-Centric Networks,” Rome, Italy., [2] Project CCNx. Sep /13 Reference