TagNet: a scalable tag-based information-centric network

The Internet has changed dramatically since the time it was created. What was originally a system to connect relatively few remote users to mainframe computers, has now become a global network of billions of diverse devices, serving a large user population, more and more characterized by wireless communication, user mobility, and large-scale, content-rich, multi-user applications that are stretching the basic end-to-end, point-to-point design of TCP/IP. In recent years, researchers have introduced the concept of Information Centric Networking (ICN). The ambition of ICN is to redesign the Internet with a new service model more suitable to today's applications and users. The main idea of ICN is to address information rather than hosts. This means that a user could access information directly, at the network level, without having to first find out which host to contact to obtain that information. The ICN architectures proposed so far are based on a "pull" communication service. This is because today's Internet carries primarily video traffic that is easy to serve through pull communication primitives. Another common design choice in ICN is to name content, typically with hierarchical names similar to file names or URLs. This choice is once again rooted in the use of URLs to access Web content. However, names offer only a limited expressiveness and may or may not aggregate well at a global scale. In this thesis we present a new ICN architecture called TagNet. TagNet intends to offer a richer communication model and a new addressing scheme that is at the same time more expressive than hierarchical names from the viewpoint of applications, and more effective from the viewpoint of the network for the purpose of routing and forwarding. For the service model, TagNet extends the mainstream "pull" ICN with an efficient "push" network-level primitive. Such push service is important for many applications such as social media, news feeds, and Internet of Things. Push communication could be implemented on top of a pull primitive, but all such implementations would suffer for high traffic overhead and/or poor performance. As for the addressing scheme, TagNet defines and uses different types of addresses for different purposes. Thus TagNet allows applications to describe information by means of sets of tags. Such tag-based descriptors are true content-based addresses, in the sense that they characterize the multi-dimensional nature of information without forcing a partitioning of the information space as is done with hierarchical names. Furthermore, descriptors are completely user-defined, and therefore give more flexibility and expressive power to users and applications, and they also aggregate by subset. By their nature, descriptors have no relation to the network topology and are not intended to identify content univocally. Therefore, TagNet complements descriptors with locators and identifiers. Locators are network-defined addresses that can be used to forward packets between known nodes (as in the current IP network); content identifiers are unique identifiers for particular blocks of content, and therefore can be used for authentication and caching. In this thesis we propose a complete protocol stack for TagNet covering the routing scheme, forwarding algorithm, and congestion control at the transport level. We then evaluate the whole protocol stack showing that (1) the use of both push and pull services at the network level reduces network traffic significantly; (2) the tree-based routing scheme we propose scales well, with routing tables that can store billions of descriptors in a few gigabytes thanks to descriptor aggregation; (3) the forwarding engine with specialized matching algorithms for descriptors and locators achieves wire-speed forwarding rates; and (4) the congestion control is able to effectively and fairly allocate all the bandwidth available in the network while minimizing the download time of an object and avoiding congestion

EDGE RELAY CASCADING TO FACILITATE REAL TIME COMMUNICATIONS

For networking scenarios in which real time traffic is exchanged between multiple participants for a given network session (e.g., a conference, a gaming session, etc.), such traffic often flows from one participant to another by passing through a server, such as a cloud server, which can be expensive and can introduce latency for the traffic. Presented herein are techniques through which mesh edge nodes can be utilized to facilitate real time communications in a manner that allows for the ability to save cloud costs

FAST EDGE ACCESS CONTROL FOR ROUTED TRAFFIC

Real-Time Communication (RTC) traffic typically leverages one or more media bridges (often located in the cloud) and, in order to reduce latency and/or offload cloud resources to the edge, one or more real-time edge relays can be utilized in order to optimize such traffic. Presented herein are techniques to secure a media edge relay node without requiring an authentication for a connection involving the media edge relay node

RELIABLE INTERESTS IN INFORMATION-CENTRIC NETWORKING

In an information-centric networking (ICN) environment, an interest may be dropped by a network for any number of reasons. However, if an interest is lost then the corresponding data cannot be received, thereby reducing the performance of a network. Techniques are presented herein that make ICN interests more resilient to potential losses by adding certain state information into an interest payload. That state information may be used to keep track of the previous interests that have been sent by a forwarder face for a specific name. To encode the sequence numbers of the interests that have been previously sent, a first aspect of the presented techniques employs a list of sequence numbers while a second aspect of the presented techniques employs a bitmap. The presented techniques may be used to reduce the possibility that interests are not dropped during transit when using ICN

TECHNIQUES TO PROVIDE EDGE RELAYS WITH PRIVACY-PRESERVING CACHES

Real-Time Communication (RTC) traffic typically leverages one or more media bridges (often located in the cloud) and, in order to reduce latency and/or offload cloud resources to the edge, one or more real-time edge relays can be utilized in order to optimize such traffic. However, edge relays may also be exploited by malicious entities and, thus, certain protective mechanisms are typically utilized at edge relays that, while reducing the probability of being exploited, can reduce the throughput of such edge relays. Techniques presented herein may help to preserve data privacy at edge relays through the use of a time-local caching mechanism

Search for Eccentric Black Hole Coalescences during the Third Observing Run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass $M>70$ $M_\odot$) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities $0 < e \leq 0.3$ at $0.33$ Gpc$^{-3}$ yr$^{-1}$ at 90\% confidence level.Comment: 24 pages, 5 figure

Content-based publish/subscribe networking and information-centric networking

On-line information comes in different forms and is accessed in different ways and for different purposes. For example, a recording of Beethoven’s Ninth Symphony differs from a storm warning from the local weather service. Beethoven’s Ninth is a large media file with perpetual validity that is typically accessed on demand by users. By contrast, a storm warning is a small ephemeral message typically pushed by the weather service to all users in a specific geographic area. We argue that both should and would be well supported by an information-centric network. More specifically we argue three points. First, modern applications, reflecting the nature of human communications, use and transmit large and long-lived files as well as small ephemeral messages. Second, accessing those two types of information involves significantly different operations within the network. Third, despite their differences, both types of information would benefit from an addressing scheme based on content rather than on more or less flat identifiers, which means that both should be integrated to some extent within a unified contentbased routing infrastructure

Multipath Congestion Control in Content-Centric Networks

Abstract—Data communication across the Internet has significantly changed under the pressure of massive content delivery. Content-Centric Networking (CCN) rethinks Internet communication paradigm around named data retrieval, in contrast with the host-to-host transport model of TCP/IP. Content retrieval is natively pull-based driven by user requests, point-to-multipoint and intrinsically coupled with the availability of network storage. By leveraging the key features of CCN transport, in this paper we propose for the first time a congestion control mechanism realizing efficient multipath communication over content-centric networks. Our proposal is based on a Remote Adaptive Active Queue Management (RAAQM) at the receiver that performs a per-route control of bottleneck queues along the paths. We analyze the stability of the proposed solution and assess its performance by means of CCN packet-level simulations under random and optimal route selection. I