ICNRG K. Pentikousis Internet-Draft Huawei Intended Status: Informational B. Ohlman Expires: May 10, 2013 Ericsson November 6, 2012 ICN Baseline Scenarios draft-pentikousis-icn-scenarios-00 Abstract This document presents scenarios for information-centric networking (ICN) which can be used to establish a common understanding about potential experimental setups where different approaches can be tested and compared against each other. The scenarios are primarily based on published literature, that is, they have all been considered in one or more performance evaluation studies, which are already available to the community. The scenarios selected for inclusion in this first draft aim to exercise a variety of aspects that an ICN solution can address. They include a) general aspects, such as, network efficiency, mobility support, multicast and caching performance, real-time communication efficacy, disruption and delay tolerance; and b) ICN-specific aspects, such as, information security and trust, persistence, availability, provenance, and location independence. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." 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Table of Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2 2 ICN Baseline Scenarios . . . . . . . . . . . . . . . . . . . . 3 2.1 Social Networking . . . . . . . . . . . . . . . . . . . . . 3 2.2 Real-time A/V Communications . . . . . . . . . . . . . . . 4 2.3 Mobile Networking . . . . . . . . . . . . . . . . . . . . . 5 2.4 Infrastructure Sharing . . . . . . . . . . . . . . . . . . 6 2.5 Content Dissemination . . . . . . . . . . . . . . . . . . . 7 2.6 Energy Efficiency . . . . . . . . . . . . . . . . . . . . . 8 2.7 Delay and Disruption Tolerance . . . . . . . . . . . . . . 8 3 Security Considerations . . . . . . . . . . . . . . . . . . . . 8 4 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8 5 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 8 6 Informative References . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10 1 Introduction Information-centric networking (ICN) marks a fundamental shift in communications and networking. In contrast with the omnipresent, and very successful we may add, host-centric paradigm, based on perpetual connectivity and the end-to-end principle, ICN changes the focal point of the network architecture from the "end host" to "information" (or content, or data). In this paradigm, connectivity can be intermittent in general; end-host and in-network storage can be capitalized upon transparently as bits in the network and on some storage device have exactly the same value; mobility, multicasting and multiaccess are supported by default; and energy efficiency is a Pentikousis & Ohlman Expires May 10, 2013 [Page 2] INTERNET DRAFT ICN Baseline Scenarios November 6, 2012 design consideration from the beginning. Although interest in ICN is growing rapidly, ongoing work on different architectures, such as, for example, NetInf [NetInf], CCN and NDN [CCN], the publish-subscribe Internet (PSI) architecture [PSI], and the data-oriented architecture [DONA] is far from being completed. The increasing interest and the plethora of ICN approaches make this a very active research area but, on the downside, it makes it more difficult to compare different proposals on an equal ground. It is not uncommon that different researchers select different performance evaluation scenarios in order to highlight the advantages of their approach. This is reasonable and should be expected to some degree. As Ahlgren et al. note [SoA], describing these architectures is akin to shooting a moving target. We find that comparing these different approaches is often even more tricky. Nevertheless, certain scenarios seem to emerge where said ICN architectures could showcase their superiority over current systems, in general, and against each other, in particular. This document collects several scenarios from the published ICN literature and aims to use them as foundation for the baseline scenarios to be considered by the IRTF Information-Centric Networking Research Group (ICNRG) in its future work. The list of scenarios can obviously change, as input from the research group is received. 2 ICN Baseline Scenarios This section presents a number of scenarios grouped into several categories. Note that certain evaluation scenarios span across these categories, so the boundaries between them should not be considered rigid and inflexible. The goal is that each scenario should be described at a sufficient level of detail so that it can serve as the base for comparative evaluations of different approaches. This will need to include reference configurations, specifications of traffic mixes and traffic loads. These specifications/configurations should preferably come as sets that describe extremes as well as "typical" usage scenarios. 2.1 Social Networking Social networking applications proliferated over the past decade based on overlay content dissemination systems that require large infrastructure investments to rollout and maintain. Content dissemination is at the heart of the ICN paradigm and, therefore, we Pentikousis & Ohlman Expires May 10, 2013 [Page 3] INTERNET DRAFT ICN Baseline Scenarios November 6, 2012 would expect that they are a "natural fit" for showcasing the superiority of ICN over traditional client-server TCP/IP-based systems. Mathieu et al. [ICN-SN], for instance, illustrate how an ISP can capitalize on CCN to deploy a short-message service akin to Twitter at a fraction of the complexity of today's systems. Their key observation is that such a service can be seen as a combination of multicast delivery and caching. That is, a single user addresses a large number of recipients, some of which receive the new message immediately as they are online at that instant, while others receive the message whenever they connect to the networks. Earlier work by Arianfar et al. [CCR] considers a similar pull-based content retrieval scenario using a different architecture, pointing to significant performance advantages. Although the authors consider a different network topology and do not explicitly say that their evaluation scenario is addressing social networking, the similarities are easy to spot: "followers" obtain content put "on the network" by a single user relying solely on network primitives. That is, in both evaluations there is no need for a classic client-server architecture (let alone a cloud-based infrastructure) to intermediate between content providers and consumers. This scenario aims to exercise each ICN architecture in terms of network efficiency, multicast support, and caching performance. 2.2 Real-time A/V Communications Real-time audio and video (A/V) communications include an array of services ranging from one-to-one voice calls to multi-party multi- media conferences with video and whiteboard support to augmented reality. Real-time communications have been studied (and deployed widely) in the context of packet- and circuit-switched networks for decades. The stringent quality of service requirements that this type of communication imposes on network infrastructure is well- known. However, the ICN community has, so far, only scratched the surface of this area with respect to illustrating the benefits of adopting an information-centric approach as opposed to a host-centric one. Notably, Jacobson et al. [VoCCN] presented an early evaluation where the performance of a VoIP call over an information-centric approach was compared with that of an off-the-shelf VoIP implementation using RTP/UTP. The results indicated that despite the extra cost of adding security support in the former case, performance was virtually identical in the two cases evaluated in a testbed. However, the Pentikousis & Ohlman Expires May 10, 2013 [Page 4] INTERNET DRAFT ICN Baseline Scenarios November 6, 2012 experimental setup was was quite rudimentary and the evaluation considered a single voice call only. This scenario does illustrate that VoIP is feasible with at least one ICN approach, but it would need to be further enhanced to include more comprehensive metrics as well as standardized call arrival patterns, for example, following well-established methodologies from the quality of service/experience (QoS/QoE) evaluation toolbox. Given the wide-spread deployment of real-time A/V communications, an ICN approach should show not only feasibility but highlight that complexity is significantly reduced when compared to a classic IP- based A/V application. For example, with respect to multimedia conferencing, Zhu et al. [ACT] describe the design of a distributed audio conference tool based on NDN. The design includes ICN-based conference discovery, speakers discovery and voice data distribution. The reported evaluation results point to gains in scalability and security. Moreover, Chen et al. [G-COPSS] explore the feasibility of implementing a Massively Multiplayer Online Role Playing Game (MMORPG) based on CCNx and show that stringent temporal requirements can be met while scalability is significantly improved when compared to an IP client-server system. In short, scenarios in this category should illustrate not only feasibility but increased scalability, reliability, and capacity to meet stringent QoS/QoE requirements when compared to established host-centric solutions. 2.3 Mobile Networking IP mobility management relies on mobility anchors to provide ubiquitous connectivity to end-hosts as well as moving networks. This is a natural choice for a host-centric paradigm that requires end-to-end connectivity and continuous network presence [SCES]. An implicit assumption in host-centric mobility management frameworks is that the mobile node aims at connecting to a particular peer, not at retrieving information [EEMN]. However, with ICN new ideas about mobility management should come to the forefront, which capitalize on the different nature of the paradigm. For example, Dannewitz et al. [N-Scen], consider a scenario where a multiaccess end-host can retrieve email securely using a combination of cellular and wireless local area network connectivity. This scenario borrows elements from previous work, e.g. [DTI], and develops them further with respect to multiaccess. Unfortunately, Dannewitz et al. [N-Scen] do not present any results demonstrating that an ICN approach is indeed better. That said, the scenario is interesting as it considers content specific to a single user (i.e. Pentikousis & Ohlman Expires May 10, 2013 [Page 5] INTERNET DRAFT ICN Baseline Scenarios November 6, 2012 her mailbox) and does point to a decrease in complexity. It is also compatible with recent work in the Distributed Mobility Management (DMM) Working Group within the IETF. Finally, Xylomenos et al. [PSIMob] as well as [EEMN] argue that an information-centric architecture can avoid the complexity of having to manage tunnels to maintain end-to-end connectivity as is the case with mobile anchor- based protocols such as Mobile IP (and its variants). Overall, mobile networking scenarios have not been developed in detail, let alone evaluated in a wide scale. We expect that in the coming period more papers will address this topic, each perhaps proposing its own evaluation scenario. The scenarios in mobile networking will be naturally coupled with those discussed in the previous sections as more users access social networking and A/V applications through mobile devices. Mobile networking scenarios should aim to exercise service continuity for those applications that require it, decrease complexity and control signaling for the network infrastructure, as well as increase wireless capacity utilization by taking advantage of the broadcast nature of the medium. 2.4 Infrastructure Sharing A key idea in ICN is that the network should secure information objects per se, not the communications channel that they are delivered over. This means that hosts attached to an information- centric network can share resources in an unprecedented scale, especially when compared to what is possible in an IP network. All devices with network access and storage capacity can contribute their resources increasing the value of an information-centric network (perhaps) much faster than Metcalfe's law. For example, Jacobson et al. [CBIS] argue that in ICN the "where and how" to obtain information are new degrees of freedom. They illustrate this with a scenario involving a photo sharing application which takes advantage of whichever access network connectivity is available at the moment (WLAN, Bluetooth, and even SMS) without requiring a centralized infrastructure to synchronize between numerous devices. It is important to highlight that since the focus of the communication changes, keep-alives in this scenario are simply unnecessary, as devices participating in the testbed network contribute resources in order to maintain user content consistency, not link state information as is the case in the host-centric paradigm. This means that the notion of "infrastructure" may be completely different in the future. Pentikousis & Ohlman Expires May 10, 2013 [Page 6] INTERNET DRAFT ICN Baseline Scenarios November 6, 2012 Carofiglio et al., for instance, present early work on an analytical framework that attempts to capture the storage/bandwidth tradeoff and can be used as a basis for a network planning tool [SHARE]. In addition, Chai et al. [CL4M] explore the benefits of ubiquitous caching throughout an information-centric network and argue that "caching less can actually achieve more." These two papers indicate that there is a lot of work to be done in the area of how to use optimally all resources that end hosts bring into the network. Scenarios in this category, therefore, would cover the communication/computation/storage tradeoffs that an ICN network deployment must consider, including network planning, perhaps capitalizing on user-provided resources, as well as operational and economical aspects to illustrate the superiority of ICN over other approaches, including federations of IP-based Content Distribution Networks (CDNs). 2.5 Content Dissemination Content dissemination has attracted more attention than other aspects of ICN, perhaps due to a misunderstanding of what the first "C" in CCN stands for. Decentralized content dissemination with on-the-fly aggregation of information sources was envisaged in [N-Scen] where information objects can be dynamically assembled based on hierarchically structured subcomponents. For example, a video stream could be associated with different audio streams and subtitle sets, which all can be obtained from different sources. Semantics and content negotiation, on behalf of the user was also considered, e.g. for the case of popular tunes. Effectively this scenario has the information consumer issuing independent requests for content based on information identifiers, and stitching the pieces together irrespective of "where" or "how" they were obtained. Content dissemination scenarios have a large overlap with the scenarios described above [DONA, PSI, PSI-Mob, NetInf, CCN, CBIS, CCR], just to name a few. In addition, Chai et al. present a hop-by- hop hierarchical content resolution approach [CURLING], which employs receiver-driven multicast over multiple domains, advocating another content dissemination approach. Scenarios in this category abound in the literature, including stored and streaming A/V distribution, file distribution, mirroring and bulk transfers, SVN-type of services, as well as traffic aggregation. We expect that in particular for content dissemination both extreme as well as typical scenarios can be specified drawing data from current CDN deployments. Pentikousis & Ohlman Expires May 10, 2013 [Page 7] INTERNET DRAFT ICN Baseline Scenarios November 6, 2012 2.6 Energy Efficiency As mentioned earlier, energy efficiency can be tackled by ICN in ways that it cannot in a host-centric paradigm. For example, the work by Guan et al. [EECCN] indicates that CCN may be much more energy- efficient than traditional CDNs for delivering popular content given the current networking equipment energy consumption levels. Evaluating energy efficiency does not require the definition of new scenarios, but does require the establishment of clear guidelines so that different ICN approaches can be compared not only in terms of scalability, for example, but also in terms to power consumption. 2.7 Delay and Disruption Tolerance Delay Tolerant Networking (DTN) [DTN] was originally designed for special use cases, such as interstellar networking, use of data mules, and so on. With the advent of sensor networks and peer-to- peer (P2P) networking between mobile nodes, DTN is becoming a more commonplace type of networking. ICN does not build on the familiar communication abstraction of end-to-end connectivity between a set of nodes. This makes it possible to include DTN support in ICN natively. Thus it is of interest to evaluate to which extent different ICN technologies can support DTN scenarios. Important aspects to be evaluated with respect to delay and disruption tolerance include, but are not limited to, name resolution, routing and forwarding in disconnected parts of the network; support for unidirectional links; number of round trips needed to complete a data transfer, and so on. 3 Security Considerations TBD 4 IANA Considerations This document presents no IANA considerations. 5 Acknowledgments TBD Pentikousis & Ohlman Expires May 10, 2013 [Page 8] INTERNET DRAFT ICN Baseline Scenarios November 6, 2012 6 Informative References [NetInf] Ahlgren, B. et al., "Design considerations for a network of information", Proc. CoNEXT Re-Arch Workshop. ACM, 2008. [CCN] Jacobson, V. et al., "Networking Named Content", Proc. CoNEXT. ACM, 2009. [PSI] Trossen, D. and Parisis, G., "Designing and realizing an information-centric internet", IEEE Commun. Mag., vol. 50, no. 7, July 2012. [DONA] Koponen, T. et al., "A Data-Oriented (and Beyond) Network Architecture", Proc. SIGCOMM. ACM, 2007. [SoA] Ahlgren, B. et al., "A survey of information-centric networking", IEEE Commun. Mag., vol. 50, no. 7, July 2012. [ICN-SN] Mathieu, B. et al., "Information-centric networking: a natural design for social network applications", IEEE Commun. Mag., vol. 50, no. 7, July 2012. [CCR] Arianfar, S. et al., "On content-centric router design and implications", Proc. CoNEXT Re-Arch Workshop. ACM, 2010. [VoCCN] Jacobson, V. et al., "VoCCN: Voice-over Content-Centric Networks", Proc. CoNEXT Re-Arch Workshop. ACM, 2009. [ACT] Zhu, Z. et al., "ACT: Audio Conference Tool Over Named Data Networking", Proc. SIGCOMM ICN Workshop. ACM, 2011. [G-COPSS] Chen, J. et al., "G-COPSS: A Content Centric Communication Infrastructure for Gaming Applications", Proc. ICDCS. IEEE, 2012. [SCES] Allman, M. et al., "Enabling an Energy-Efficient Future Internet through Selectively Connected End Systems", Proc. HotNets-VI. ACM, 2007. [EEMN] Pentikousis, K., "In Search of Energy-Efficient Mobile Networking", IEEE Commun. Mag., vol. 48, no. 1, Jan. 2010. [N-Scen] Dannewitz, C. et al., "Scenarios and research issues for a Network of Information", Proc. MobiMedia. ICST, 2012. [DTI] Ott, J. and Kutscher, D., "Drive-thru Internet: IEEE 802.11b for 'automobile' users", Proc. INFOCOM. IEEE, 2004. Pentikousis & Ohlman Expires May 10, 2013 [Page 9] INTERNET DRAFT ICN Baseline Scenarios November 6, 2012 [PSIMob] Xylomenos, G. et al., "Caching and Mobility Support in a Publish-Subscribe Internet Architecture", IEEE Commun. Mag., vol. 50, no. 7, July 2012. [CBIS] Jacobson, V. et al., "Custodian-Based Information Sharing", IEEE Commun. Mag., vol. 50, no. 7, July 2012. [SHARE] Carofiglio, G. et al., "Bandwidth and storage sharing performance in information centric networking", Proc. SIGCOMM ICN Workshop. ACM, 2011. [CL4M] Chai, W. K. et al., "Cache 'Less for More' in Information- centric Networks", Proc. Networking. IFIP, 2012. [CURLING] Chai, W. K. et al., "CURLING: Content-Ubiquitous Resolution and Delivery Infrastructure for Next-Generation Services", IEEE Commun. Mag., vol. 49, no. 3, Mar. 2011. [EECCN] Guan, K. et al., "On the Energy Efficiency of Content Delivery Architectures ", Proc. ICC Workshops. IEEE, 2011. [DTN] Fall, K., "A delay-tolerant network architecture for challenged internets", Proc. SIGCOMM. ACM, 2003. Authors' Addresses Kostas Pentikousis Huawei Technologies Carnotstrasse 4 10587 Berlin Germany Email: k.pentikousis@huawei.com Borje Ohlman Ericsson Research S-16480 Stockholm Sweden Email: Borje.Ohlman@ericsson.com Pentikousis & Ohlman Expires May 10, 2013 [Page 10]