Efficient content delivery through fountain coding in opportunistic information-centric networks

Opportunistic networks can increase network capacity, support collaborative downloading of content and offload traffic from a cellular to a cellular-assisted, device-to-device network. They can also support communication and content exchange when the cellular infrastructure is under severe stress and when the network is down or inaccessible. Fountain coding has been considered as espe- cially suitable for lossy networks, providing reliable multicast transport without requiring feedback from receivers. It is also ideal for multi-path and multi- source communication that fits exceptionally well with opportunistic networks. In this paper, we propose a content-centric approach for disseminating con- tent in opportunistic networks efficiently and reliably. Our approach is based on Information-Centric Networking (ICN) and employs fountain coding. When tied together, ICN and fountain coding provide a comprehensive solution that overcomes significant limitations of existing approaches. Extensive network simulations indicate that our approach is viable. Cache hit ratio can be increased by up to five times, while the overall network traffic load is reduced by up to four times compared to content dissemination on top of the standard Named Data Networking architecture

Scaling bloom filter-based multicast via filter switching

Abstract—Stateless multicast forwarding with in-packet Bloom filters (iBF) has recently been proposed as a highly scalable way for supporting a large number of multicast groups. However, iBF multicast generates redundant traffic due to false positive forwarding decisions and it also scales poorly with multicast group size. In this paper we investigate scaling iBF multicast to arbitrary multicast group sizes, by partially sacrificing the network’s fully stateless operation. We propose a switched-iBF multicast scheme that places multicast forwarding state at a few network nodes, so as to minimize redundant traffic regardless of the group size. We evaluate the scheme through simulations and find that switched-iBF multicast can scale to any group size while keeping redundant traffic below 1%-4 % at the (minimal) cost of placing state at no more than 0.5%-2.5 % of network nodes. We also compare the state requirements of switched-iBF multicast against other multicast schemes. Our evaluation shows that switched-iBF multicast achieves a tremendous reduction of multicast state in the range of 87%-99.6%. Hence, even though the system is no more fully stateless, it remains far more scalable than other approaches. Index Terms—in-packet Bloom filters, multicast packet forwarding, switched-iBFs I

Προώθηση πολυεκπομπής σε μελλοντικά πληροφοριο-κεντρικά δίκτυα

Information-Centric Networking (ICN), an active research area in Computer Networking, has the goal of designing a network architecture that better suits today's networked world: billions of connected devices requesting access to voluminous amounts of digital media. ICN architectures aim to facilitate content distribution by placing self-identified information items at the heart of the networking protocol stack and building routing and transport protocols around them.Among other design choices, ICN emphasizes support for scalable and efficient multicast delivery. However, practical implementations of ICN architectures have found that achieving this goal is easier said than done. For instance, the Content-Centric Networking (CCN) architecture realizes single-source multicast delivery through a distributed stateful forwarding scheme, which faces scalability issues with respect to the forwarding state kept at routers. On the other hand, the Publish-Subscribe Internet (PSI) architecture proposes a centrally-controlled fully stateless multicast forwarding scheme with In-packet Bloom filters (IBF), which faces scalability issues with respect to the network and/or multicast group size. This dissertation addresses the issue of multicast forwarding scalability in two very different ICN architectures, namely CCN and PSI. The common ground in the proposed solutions is the use and extension of Bloom filter-based packet forwarding mechanisms. In CCN, we relax the fully stateful nature of its forwarding scheme, in order to improve the architecture's scalability with respect to the forwarding state kept at routers. We propose a semi-stateless forwarding scheme by incorporating Bloom filter-based forwarding, while respecting the architecture's distributed routing and forwarding operations. Our simulation-based study shows that the scheme can effectively reduce forwarding state at routers by 60%-70% at the cost of 1.5%-12% in bandwidth overhead.In PSI, we similarly relax the fully stateless nature of its forwarding scheme, proposing a semi-stateless alternative with IBF switching, in order to allow IBFs to efficiently scale to any network and/or multicast group size. We integrate IBF switching in PSI, utilizing the architecture's centralized control-plane operations. Our simulation-based study shows that with IBF switching, forwarding scalability is achieved regardless of network and/or multicast group size, at the cost of placing forwarding state at 0.5%-2.5% of forwarding nodes, which is far less than that of competing technologies.Τα Πληροφοριο-Κεντρικά Δίκτυα (ΠΚΔ) είναι μια δραστήρια ερευνητική περιοχή στο πεδίο των Δικτύων Υπολογιστών και έχουν ως στόχο τη σχεδίαση αρχιτεκτονικών δικτύωσης κατάλληλες για τις σημερινές τεχνολογικές ανάγκες: δισεκατομμύρια συνδεδεμένων συσκευών με πρόσβαση σε τεράστιους όγκους ψηφιακού περιεχομένου. Οι αρχιτεκτονικές ΠΚΔ προσβλέπουν στη βελτίωση της διανομής περιεχομένου τοποθετώντας την έννοια του Αντικειμένου Πληροφορίας στη καρδιά της στοίβας πρωτοκόλλων και χτίζοντας μηχανισμούς δικτύωσης (δρομολόγηση, προώθηση, μεταφορά) γύρω από αυτή.Μεταξύ άλλων επιλογών, τα ΠΚΔ δίνουν ιδιαίτερη έμφαση στην αποδοτική και κλιμακώσιμη προώθηση πολυεκπομπής. Παρόλα αυτά, οι πρώτες υλοποιήσεις ΠΚΔ έδειξαν ότι αυτός ο στόχος επιτυγχάνεται δυσκολότερα από ό,τι είχε αρχικά εκτιμηθεί. Για παράδειγμα, η αρχιτεκτονική Content-Centric Networking (CCN) εφαρμόζει ένα σχήμα κατανεμημένης προώθησης που απαιτεί τη τοποθέτηση πληροφορίας προώθησης στους δρομολογητές και το οποίο αντιμετωπίζει ζητήματα κλιμακωσιμότητας ως προς τον όγκο μνήμης που απαιτείται στους δρομολογητές. Παράλληλα, η αρχιτεκτονική Publish-Subscribe Internet (PSI) προτείνει τη χρήση προώθησης πηγής όπου η πληροφορία προώθησης τοποθετείται στα πακέτα δεδομένων με τη μορφή Bloom filter, αλλά αυτή η τεχνική αντιμετωπίζει ζητήματα κλιμακωσιμότητας ως προς το μέγεθος του δικτύου ή/και της ομάδας παραληπτών.Η παρούσα διατριβή θέτει το θέμα της κλιμακωσιμότητας ως προς τη προώθηση πολυεκπομπής σε δύο ΠΚΔ αρχιτεκτονικές, τις CCN και PSI. Ο κοινός παρανομαστής των προτεινόμενων λύσεων είναι η χρήση και επέκταση της προώθησης πακέτων με Bloom filters. Στο CCN, αφαιρούμε πληροφορία προώθησης από τους δρομολογητές και τη μεταφέρουμε στα πακέτα. Προτείνουμε ένα υβριδικό σχήμα προώθησης εισάγοντας προώθηση πηγής με Bloom filters στην αρχιτεκτονική και παράλληλα διατηρώντας τον κατανεμημένο τρόπο λειτουργίας του δικτύου. Η αξιολόγηση μέσω προσομοίωσης έδειξε ότι η προτεινόμενη λύση μειώνει τις απαιτήσει μνήμης των δρομολογητών κατά 60%-70% με το κόστος 1.5%-12% επιπρόσθετου φορτίου κίνησης.Στο, PSI, παρόμοια εφαρμόζουμε μια υβριδική τεχνική προώθησης με τοποθέτηση πληροφορίας τόσο στα πακέτα όσο και στους δρομολογητές με στόχο την αποδοτική πολυεκπομπή σε κάθε μέγεθος δικτύου ή/και πλήθος παραληπτών. Η τεχνική λειτουργεί με κεντρικοποιημένο τρόπο και είναι κατάλληλα σχεδιασμένη για να ενσωματωθεί στο PSI που επίσης εφαρμόζει μια κεντρικοποιημένη φιλοσοφία. Η αξιολόγηση μέσω προσομοίωσης έδειξε ότι η λύση επιτυγχάνει αποδοτική πολυεκπομπή με το κόστος τοποθέτησης πληροφορίας προώθησης σε 0.5%-2.5% των δρομολογητών, που είναι συγκριτικά λιγότερο από αντίστοιχες τεχνολογίες πολυεκπομπής

Supporting diverse traffic types in information centric networks

In this paper we focus on the issue of transferring diverse kinds of information through information-centric networks (ICNs). We argue that the one request per packet mode of operation suggested in the early development of ICN applications is not a good fit for some types of traffic, such as media streams and real-time notifications. To efficiently deliver all kinds of information, we argue that an ICN should not only identify information by its name, it should also be aware of the nature of its traffic. We classify information traffic types based on two characteristics: a) reliable vs. unreliable transfer and b) real-time vs. on-demand delivery. The combination of these two characteristics leads to three broad categories: a) channels, b) on-demand documents and c) real-time documents. To handle all traffic types, we propose two extensions to the CCN architecture: Persistent Interests and Reliable Notifications. We describe how these additions, together with a careful selection of information names, can efficiently support these three categories of information traffic types

Adaptive timeout policies for wireless links

A considerable body of evidence indicates that the use of reliable link layer protocols over error prone wireless links dramatically improves the performance of Internet protocols and applications. While traditional link layer protocols set their timeout values assuming that they fully control the underlying link, some wireless networks allow multiple link layer sessions to co-exist over the same link. Since the optimal timeout values for a reliable link layer protocol depend on the available bandwidth, with dynamic link sharing such a protocol should ideally adapt its timeout values accordingly. We have thus designed an Adaptive Selective Repeat protocol that modifies its timeout values based on the policy used by TCP. We compare the performance of Web Browsing over Selective Repeat when using our adaptive timeout scheme with a range of parameters, against a manually tuned fixed timeout version. Our measurements show that these adaptive timeout policies outperform the fixed one, regardless of the level of contention, and that the best adaptive timeout policy in this setting is not the one used by TCP. © 2006 IEEE

Multisource and multipath file transfers through publish-subscribe internetworking

We present mmFTP, an information-centric and receiver-driven file transfer protocol for the Publish Subscribe Internetworking (PSI) architecture. mmFTP supports both multisource and multipath transfers, while requiring minimal complexity in terms of network operation. We describe the basic design and operation of mmFTP and present preliminary experimental performance results from a prototype implementation deployed in the PlanetLab testbed. Copyright © 2013 ACM

Efficient real-time information delivery in Future Internet Publish-Subscribe Networks

In this paper we explain how efficient delivery of real-time information can be supported in the Publish Subscribe Internet (PSI), a network architecture proposal for the Future Internet. PSI departs from IP thinking with respect to the core abstractions made and the functional organization of the system. PSI places information at the heart of the network layer and decouples the forwarding, path formation and topology management functionalities. This design approach can be highly beneficial for real-time communications, as it enables the network to apply sophisticated mechanisms for multicast tree construction, such as delivery of information over optimal (minimum cost) Steiner trees. Initial experiments with a proof-of-concept implementation of PSI indicate the feasibility of realizing such optimization policies. Our results show that significant bandwidth savings can be achieved at the cost of small, unnoticeable to the end-users, delays in flow establishment. © 2013 IEEE

Caching and mobility support in a publish-subscribe internet architecture

The Internet is straining to meet demands that its design never anticipated, such as supporting billions of mobile devices and transporting huge amounts of multimedia content. The publish-subscribe Internet (PSI) architecture, a clean slate information-centric networking approach to the future Internet, was designed to satisfy the current and emerging user demands for pervasive content delivery, which the Internet can no longer handle. This article provides an overview of the PSI architecture, explaining its operation from bootstrapping to information delivery, focusing on its support for network layer caching and seamless mobility, which make PSI an excellent platform for ubiquitous information delivery. © 2012 IEEE