Charge routing networking : using lightning strikes to add dynamicity to CCN

Abstract

This thesis presents a novel routing mechanism designed to improve the performance of information-centric networks where there is a large degree of content producer mobility. Usage patterns on the Internet have changed a lot since the network was first designed and deployed in the 1960ies. From being a point-to-point communications and resource sharing platform, the Internet has evolved into the planet's premier content distribution platform. This change in the way the network is being used means that the underlying transport mechanisms, in the form of TCP, UDP, and IP, are no longer as well suited to catering for the network's netizens as they were when they were first designed. Where the protocols concern themselves with transporting opaque data streams from one named endpoint in the network to another, their users are more concerned with what data is delivered to their systems and less with where it came from. Users no longer care whether they are connected to a server in Ireland or Columbia, as long as it delivers the content they request from it. As a result, a research sphere has sprung up around a replacement paradigm called Information-Centric Networking (ICN). ICNs make content, and the names that it is addressable by, the primary routing mechanism in the network, rather than IP addresses as is the case today. This makes them uniquely suitable to servicing the needs of modern users, in that both network and users can now focus on what content is delivered rather than where to retrieve it from. ICNs typically provide features such as name-based routing, which alleviates the need for name resolution overlays such as the Domain Name System, in-network caching, which decreases the network traffic by utilizing nearby copies of requested content, and intrinsic content consumer mobility, which allows user nodes to roam freely throughout the network without having to be assigned domain-specific addresses, as is the case with IP. In this thesis, we address an oft-overlooked network feature: Content producer mobility. It is a feature that still requires research to be fully supported in ICNs without resorting to using mobility anchors or a partially-fixed infrastructure. Our starting point is one ICN in particular - Content-Centric Networking (CCN) - and we present extensions that allow it to support a fully-mobile network infrastructure. We choose to focus on CCN because it is the most well-supported and mature of the ICNs currently out there. We expand CCN into a new paradigm, called Charge Routing Networking (CRN) that allows for a much greater degree of flexibility toward mobile content producers than CCN. CRN takes inspiration from how lightning strikes work in nature and model a transfer of content from a producer to a consumer in the same way as a lightning bolt transfers charge from a cloud to the ground. With CRN, producers can pre-seed paths in the network, which let consumers discover the content that the producers make available, by making a series of path-of-least-resistance routing decisions. We experimentally demonstrate and evaluate the features of CRN and compare them to their CCN counterparts in a collection of simulated networks. We simulate two applications in these networks: A high-throughput, latency-sensitive video streaming application, and a low-throughput, non-latency-sensitive Twitter-like social networking application. We show how CRN can outperform CCN by on average 38% to 79%, measured on delivery faults under the streaming application, and 6% to 38%, measured on content delivery volume under the social networking application. We also show how, when the overhead of the extra traffic introduced by CRN is low compared to the total traffic volume, or when node churn in the network is modest, CRN achieves this using on average 3% to 84% less total traffic than the comparable CCN solution. In the best cases, CRN can reduce delivery faults by more than 99% and decrease traffic volume by 97%. Finally, we show that at the very worst case - low throughput, high CRN overhead – CRN can consume up to four and a half times more network traffic than CCN under similar conditions. We conclude from this thesis that CRN can indeed make a big difference in the number of delivery faults with latency-sensitive applications and the amount of content the network can deliver in a given time with non-latency-sensitive applications. These are the metrics of our simulations, and in all but the worst cases, CRN improves – sometimes significantly - on the performance of CCN when run in head-to-head comparison scenarios. Actual results in a given situation depend on the applications being serviced by the network and the churn in mobile nodes. Best results are achieved when application throughput in the network is high, and node churn is moderate. This thesis presents a novel routing mechanism designed to improve the performance of information-centric networks where there is a large degree of content producer mobility. Usage patterns on the Internet have changed a lot since the network was first designed and deployed in the 1960ies. From being a point-to-point communications and resource sharing platform, the Internet has evolved into the planet's premier content distribution platform. This change in the way the network is being used means that the underlying transport mechanisms, in the form of TCP, UDP, and IP, are no longer as well suited to catering for the network's netizens as they were when they were first designed. Where the protocols concern themselves with transporting opaque data streams from one named endpoint in the network to another, their users are more concerned with what data is delivered to their systems and less with where it came from. Users no longer care whether they are connected to a server in Ireland or Columbia, as long as it delivers the content they request from it. As a result, a research sphere has sprung up around a replacement paradigm called Information-Centric Networking (ICN). ICNs make content, and the names that it is addressable by, the primary routing mechanism in the network, rather than IP addresses as is the case today. This makes them uniquely suitable to servicing the needs of modern users, in that both network and users can now focus on what content is delivered rather than where to retrieve it from. ICNs typically provide features such as name-based routing, which alleviates the need for name resolution overlays such as the Domain Name System, in-network caching, which decreases the network traffic by utilizing nearby copies of requested content, and intrinsic content consumer mobility, which allows user nodes to roam freely throughout the network without having to be assigned domain-specific addresses, as is the case with IP. In this thesis, we address an oft-overlooked network feature: Content producer mobility. It is a feature that still requires research to be fully supported in ICNs without resorting to using mobility anchors or a partially-fixed infrastructure. Our starting point is one ICN in particular - Content-Centric Networking (CCN) - and we present extensions that allow it to support a fully-mobile network infrastructure. We choose to focus on CCN because it is the most well-supported and mature of the ICNs currently out there. We expand CCN into a new paradigm, called Charge Routing Networking (CRN) that allows for a much greater degree of flexibility toward mobile content producers than CCN. CRN takes inspiration from how lightning strikes work in nature and model a transfer of content from a producer to a consumer in the same way as a lightning bolt transfers charge from a cloud to the ground. With CRN, producers can pre-seed paths in the network, which let consumers discover the content that the producers make available, by making a series of path-of-least-resistance routing decisions. We experimentally demonstrate and evaluate the features of CRN and compare them to their CCN counterparts in a collection of simulated networks. We simulate two applications in these networks: A high-throughput, latency-sensitive video streaming application, and a low-throughput, non-latency-sensitive Twitter-like social networking application. We show how CRN can outperform CCN by on average 38% to 79%, measured on delivery faults under the streaming application, and 6% to 38%, measured on content delivery volume under the social networking application. We also show how, when the overhead of the extra traffic introduced by CRN is low compared to the total traffic volume, or when node churn in the network is modest, CRN achieves this using on average 3% to 84% less total traffic than the comparable CCN solution. In the best cases, CRN can reduce delivery faults by more than 99% and decrease traffic volume by 97%. Finally, we show that at the very worst case - low throughput, high CRN overhead – CRN can consume up to four and a half times more network traffic than CCN under similar conditions. We conclude from this thesis that CRN can indeed make a big difference in the number of delivery faults with latency-sensitive applications and the amount of content the network can deliver in a given time with non-latency-sensitive applications. These are the metrics of our simulations, and in all but the worst cases, CRN improves – sometimes significantly - on the performance of CCN when run in head-to-head comparison scenarios. Actual results in a given situation depend on the applications being serviced by the network and the churn in mobile nodes. Best results are achieved when application throughput in the network is high, and node churn is moderate.