Apr 302013

Version 0.4 of the Blackadder ICN prototype is now out on GitHub. This release includes topology management extensions for traffic engineering, QoS and information resiliency, as well as various other improvements and updates. And although this is the final release in the PURSUIT project, Blackadder will be updated in the future as well!

SDN Demonstration Videos

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Oct 152012

The SDN (Story Delivery Network) is a collaborative effort between the University of Cambridge and CTVC Ltd (both are partners of the FP7 Pursuit project) in which we are seeking to deliver media-based stories over a network. In order to demonstrate the efficacy of our approach, we have implemented a media-delivery application that pulls media from available network resources and stitches it together at the player.

Although we consider that this is an advanced method for media delivery, it is certainly not new (or unique). The emphasis of this work, however, is that by placing this delivery method within an Information-centric network (such as our own), much of the required implementation is handled (or at least enabled) natively by the network. We would suggest that it is always better to consider systems that provide the required functionality natively rather than seeking to retro-fit alternative systems (just because you can!).

We have produced three short videos to describe the operation of the SDN. The demo is in three parts;

Part 1: Intro to the SDN – changing the way we disseminate media.

Part 2: The search for media – how the SDN, enabled by the middleware, can be used to search for media.

Part 3: The delivery – pull media from the publishers and stitch together at the subscriber.

We hope you enjoy this quick introduction. Please get in touch if you have any comments or questions!

Aug 032012

We’ve updated our Deliverables page with a list of deliverables from PURSUIT that we have produced throughout the year. You can now find updates to the architecture (as well as a security analysis), information about implementation components, integration as well as demonstration, evaluation at architectural and business level and (last but not least) information about our dissemination activities within the project.

So check it out – there is lots of information available!

 Posted by at 13:16
Jul 102012

Since our PSIRP efforts, much work has gone into design and realisation of our vision that is the information-centric networking (ICN) Internet. PURSUIT continued this work since September 2010.

The IEEE Communications Magazine has now run a number of special issue articles on the ICN topic. The efforts in PURSUIT are represented by two articles (among 5 total articles – that’s a great achievement!), one on caching and mobility (discussed here) and one on the overall design and implementation. In the latter article by George Parisis and myself, you can find the main design tenets, the fundamental layering in our design approach as well as the realisation of all of this within our line-speed prototype Blackadder. This article, needless to say, is the result of the many discussions and the hard work of the wider PURSUIT team.

For those of you who have followed our deliverables, much of the text will be well-known. It serves, however, as an anchor point for references to our design and implementation work that can be used by ourselves and others who find the PURSUIT work relevant. It also provides some new insights into the performance of our prototype, and we also illustrate the layering tenet through a segmentation example that utilises algorithmic identification as a neat approach to relate seemingly unrelated information items through algorithmic relations that are embedded into the item identifiers.

A section that we added based on the feedback from the editors showcases how we see other ICN architectures (including today’s IP) being enabled by the design tenets that we bring forward in this article. While we haven’t gone through all of the necessary details for this enablement, we do assert that there is a common set of tenets that can enable a breadth of design choices, such as CCN/NDN, NetInf and others. What is missing, however, is a concise and deep write-up on this aspect – a long-lived exercise that keeps getting pushed down the line of writing, it seems.

Check out the article through IEEE explore or send an email for a copy.

 Posted by at 14:25
Jun 062012

Contrary to TCP’s inherent location-dependency, Information-Centric Networking (ICN) architectures employ a receiver-driven model where (i) receivers request content by its name, (ii) in an asynchronous and (iii) connectionless (stateless) manner. Hence ICN architectures are mobile-friendly by design, as mobile receivers can re-send requests for content not received after handing over to other locations, without any need for re-establishing a point-to-point connection. Nevertheless, there are still issues with respect to delay and jitter as well as the demand for lossless transmission of data during a mobile’s disconnection period, crucial for applications with strict performance requirements such as real-time emergency notification services, multimedia streaming and event notification services.

We present Selective Neighbor Caching (SNC), a seamless mobility enhancement solution for ICN architectures to appear in the upcoming ICN’12 workshop, which will take place in Helsinki, Finland in conjunction with the ACM SIGCOMM 2012 conference, in August 2012. SNC is an approach that aims exactly at minimizing the delay in receiving data experienced by mobiles after handing off to another network location. In order to do so, SNC defines and minimizes a target cost function which captures the tradeoff between delay and caching costs.

To satisfy the above delay optimization criterion, SNC exploits the knowledge inferred by information requests issued by mobile nodes due to the receiver-driven model in ICN. Moreover, it leverages the knowledge of users’ mobility behavior. Unlike other proactive caching approaches which blindly cache items at every cache available, SNC defines a simple, decentralized and distributed procedure for selecting only an appropriate subset of neighboring proxies, i.e. proxies lying one hop away from a mobile’s last known network location, responsible for handling information requests on behalf of mobiles, pre-fetching and proactively caching desired information items matching the mobiles’ requests while the latter remains disconnected during the hand-off phase.

Jun 012012

A common starting point among ICN efforts (and clean-slate designs in general) is the mismatch between the TCP/IP core design goals and current Internet usage. Despite this common starting point however, there have been quite a few different design proposals for ICN (e.g. DONA, CCN and CONET to name a few), with similarities and dissimilarities among them when it comes to functional organization, the mechanisms adopted and the service models provided.

The upcoming special issue of the IEEE Communications Magazine on Information-centric networks (expected for July 2012) will feature an article that describes the PURSUIT architecture at some level of detail, filling a gap in the ICN literature and clearing the picture of what PURSUIT does for ICN. The architecture described in the article is a product of collective work that has taken place in both PURSUIT and PSIRP, PURSUIT’s ancestor project.

In the article we provide a thorough description of how several things are realized in PURSUIT, such as locating an item (commonly referred to as name-based routing), managing the network topology through an explicit topology management system and forwarding data with new, novel forwarding techniques such as LIPSIN. Apart from the technical description, we also point out the clear separation of the network core functions, that is, Rendezvous, Topology and Forwarding, an approach that has been a main driver in PURSUIT thinking.

Based on this architectural background, the paper proceeds to show how PURSUIT can accommodate dedicated content replication operators (similar to today’s CDNs), acting as mediators between information providers who can offload content distribution and access networks who minimize inter-domain traffic and improve user experience in turn. With respect to caching, PURSUIT supports two options: (i) on-path caching that can take place at any nodes throughout transport paths according to local policies, (ii) οff-path caching that allows access networks to orchestrate local caching of popular information. Both forms of caching allow for avoiding needless connectivity costs by network providers and improving quality of experience for users.

Finally, PURSUIT provides native mobility support, as it decouples information resolution from data transfer in both time and space. Regarding time, information providers and consumers do not need to be simultaneously connected to the network. Regarding space, information consumers can be served by any source providing the desired information, e.g., depending on location, even for different chunks of the same item. Since caching is also an integral part of PURSUIT, it is far easier to serve mobile devices from current or recent attachment points than it is with today’s IP architecture.

A pre-print version of the article  is available online.