UKAIRO: internet-scale bandwidth detouring

The performance of content distribution on the Internet is crucial for many services. While popular content can be delivered efficiently to users by caching it using content delivery networks, the distribution of less popular content is often constrained by the bandwidth of the Internet path between the content server and the client. Neither can influence the selected path and therefore clients may have to download content along a path that is congested or has limited capacity. We describe UKAIRO, a system that reduces Internet download times by using detour paths with higher TCP throughput. UKAIRO first discovers detour paths among an overlay network of potential detour hosts and then transparently diverts HTTP connections via these hosts to improve the throughput of clients downloading from content servers. Our evaluation shows that by performing infrequent bandwidth measurements between 50 randomly selected PlanetLab hosts, UKAIRO can identify and exploit potential detour paths that increase the median bandwidth to public Internet web servers by up to 80%

Improving End-to-End Internet Performance by Detouring

The Internet provides a best-effort service, which gives a robust fault-tolerant network. However, the performance of the paths found in regular Internet routing is suboptimal. As a result, applications rarely achieve all the benefits that the Internet can provide. The problem is made more difficult because the Internet is formed of competing ISPs which have little incentives to reveal information about the performance of Internet paths. As a result, the Internet is sometimes referred as a ‘black-box’. Detouring uses routing overlay networks to find alternative paths (or detour paths) that can improve reliability, latency and bandwidth. Previous work has shown detouring can improve the Internet. However, one important issue remains—how can these detour paths be found without conducting large-scale measurements? In this thesis, we describe practical methods for discovering detour paths to improve specific performance metrics that are scalable to the Internet. Particularly we concentrate our efforts on two metrics, latency and bandwidth, which are arguably the two most important performance metrics for end-user’s applications. Taking advantage of the Internet topology, we show how nodes can learn about segments of Internet paths that can be exploited by detouring leading to reduced path latencies. Next, we investigate bandwidth detouring revealing constructive detour properties and effective mechanisms to detour paths in overlay networks. This leads to Ukairo, our bandwidth detouring platform that is scalable to the Internet and tcpChiryo, which predicts bandwidth in an overlay network through measuring a small portion of the network

Revisiting Resource Pooling: The Case for In-Network Resource Sharing.

We question the widely adopted view of in-network caches acting as temporary storage for the most popular content in Information-Centric Networks (ICN). Instead, we propose that in-network storage is used as a place of temporary custody for incoming content in a store and forward manner. Given this functionality of in-network storage, senders push content into the network in an open-loop manner to take advantage of underutilised links. When content hits the bottleneck link it gets re-routed through alternative uncongested paths. If alternative paths do not exist, incoming content is temporarily stored in in-network caches, while the system enters a closed-loop, back-pressure mode of operation to avoid congestive collapse. Our proposal follows in spirit the resource pooling principle, which, however, is restricted to end-to-end resources and paths. We extend this principle to also take advantage of in-network resources, in terms of multiplicity of available sub-paths (as compared to multihomed users only) and in-network cache space. We call the proposed principle In-Network Resource Pooling Principle (INRPP). Using the INRPP, congestion, or increased contention over a link, is dealt with locally in a hop-by-hop manner, instead of end-to-end. INRPP utilises resources throughout the network more efficiently and opens up new directions for research in the multipath routing and congestion control areas

Transparent heterogeneous terrestrial optical communication networks with phase modulated signals

This thesis presents a large scale numerical investigation of heterogeneous terrestrial optical communications systems and the upgrade of fourth generation terrestrial core to metro legacy interconnects to fifth generation transmission system technologies. Retrofitting (without changing infrastructure) is considered for commercial applications. ROADM are crucial enabling components for future core network developments however their re-routing ability means signals can be switched mid-link onto sub-optimally configured paths which raises new challenges in network management. System performance is determined by a trade-off between nonlinear impairments and noise, where the nonlinear signal distortions depend critically on deployed dispersion maps. This thesis presents a comprehensive numerical investigation into the implementation of phase modulated signals in transparent reconfigurable wavelength division multiplexed fibre optic communication terrestrial heterogeneous networks. A key issue during system upgrades is whether differential phase encoded modulation formats are compatible with the cost optimised dispersion schemes employed in current 10 Gb/s systems. We explore how robust transmission is to inevitable variations in the dispersion mapping and how large the margins are when suboptimal dispersion management is applied. We show that a DPSK transmission system is not drastically affected by reconfiguration from periodic dispersion management to lumped dispersion mapping. A novel DPSK dispersion map optimisation methodology which reduces drastically the optimisation parameter space and the many ways to deploy dispersion maps is also presented. This alleviates strenuous computing requirements in optimisation calculations. This thesis provides a very efficient and robust way to identify high performing lumped dispersion compensating schemes for use in heterogeneous RZ-DPSK terrestrial meshed networks with ROADMs. A modified search algorithm which further reduces this number of configuration combinations is also presented. The results of an investigation of the feasibility of detouring signals locally in multi-path heterogeneous ring networks is also presented

Tractable Resource Management with Uplink Decoupled Millimeter-Wave Overlay in Ultra-Dense Cellular Networks

The forthcoming 5G cellular network is expected to overlay millimeter-wave (mmW) transmissions with the incumbent micro-wave ({\mu}W) architecture. The overall mm-{\mu}W resource management should therefore harmonize with each other. This paper aims at maximizing the overall downlink (DL) rate with a minimum uplink (UL) rate constraint, and concludes: mmW tends to focus more on DL transmissions while {\mu}W has high priority for complementing UL, under time-division duplex (TDD) mmW operations. Such UL dedication of {\mu}W results from the limited use of mmW UL bandwidth due to excessive power consumption and/or high peak-to-average power ratio (PAPR) at mobile users. To further relieve this UL bottleneck, we propose mmW UL decoupling that allows each legacy {\mu}W base station (BS) to receive mmW signals. Its impact on mm-{\mu}W resource management is provided in a tractable way by virtue of a novel closed-form mm-{\mu}W spectral efficiency (SE) derivation. In an ultra-dense cellular network (UDN), our derivation verifies mmW (or {\mu}W) SE is a logarithmic function of BS-to-user density ratio. This strikingly simple yet practically valid analysis is enabled by exploiting stochastic geometry in conjunction with real three dimensional (3D) building blockage statistics in Seoul, Korea.Comment: to appear in IEEE Transactions on Wireless Communications (17 pages, 11 figures, 1 table

Transparent heterogeneous terrestrial optical communication networks with phase modulated signals

This thesis presents a large scale numerical investigation of heterogeneous terrestrial optical communications systems and the upgrade of fourth generation terrestrial core to metro legacy interconnects to fifth generation transmission system technologies. Retrofitting (without changing infrastructure) is considered for commercial applications. ROADM are crucial enabling components for future core network developments however their re-routing ability means signals can be switched mid-link onto sub-optimally configured paths which raises new challenges in network management. System performance is determined by a trade-off between nonlinear impairments and noise, where the nonlinear signal distortions depend critically on deployed dispersion maps. This thesis presents a comprehensive numerical investigation into the implementation of phase modulated signals in transparent reconfigurable wavelength division multiplexed fibre optic communication terrestrial heterogeneous networks. A key issue during system upgrades is whether differential phase encoded modulation formats are compatible with the cost optimised dispersion schemes employed in current 10 Gb/s systems. We explore how robust transmission is to inevitable variations in the dispersion mapping and how large the margins are when suboptimal dispersion management is applied. We show that a DPSK transmission system is not drastically affected by reconfiguration from periodic dispersion management to lumped dispersion mapping. A novel DPSK dispersion map optimisation methodology which reduces drastically the optimisation parameter space and the many ways to deploy dispersion maps is also presented. This alleviates strenuous computing requirements in optimisation calculations. This thesis provides a very efficient and robust way to identify high performing lumped dispersion compensating schemes for use in heterogeneous RZ-DPSK terrestrial meshed networks with ROADMs. A modified search algorithm which further reduces this number of configuration combinations is also presented. The results of an investigation of the feasibility of detouring signals locally in multi-path heterogeneous ring networks is also presented.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Characterizing and Improving the Reliability of Broadband Internet Access

In this paper, we empirically demonstrate the growing importance of reliability by measuring its effect on user behavior. We present an approach for broadband reliability characterization using data collected by many emerging national initiatives to study broadband and apply it to the data gathered by the Federal Communications Commission's Measuring Broadband America project. Motivated by our findings, we present the design, implementation, and evaluation of a practical approach for improving the reliability of broadband Internet access with multihoming.Comment: 15 pages, 14 figures, 6 table