Content Delivery Networks (CDNs) have been pivotal in the dramatic evolution of the Internet, handling the majority of data traffic for billions of connected users. Low-Earth-Orbit (LEO) satellite networks, such as Starlink, aim to revolutionize global connectivity by providing high-speed, low-latency Internet to remote regions. However, LEO satellite networks (LSNs) face challenges integrating with traditional CDNs, which rely on geographical proximity for efficient content delivery - a method that clashes with the operational dynamics of LSNs. In this paper, we scrutinize the operation of CDNs in the context of LSNs, using Starlink as a case study. We develop a browser extension NetMet that performs extensive web browsing experiments from controlled nodes using both Starlink and terrestrial Internet access. Additionally, we analyse crowdsourced speed tests from Starlink users to Cloudflare CDN servers globally. Our results indicate significant performance issues for Starlink users, stemming from the misalignment between terrestrial and satellite infrastructures. We then investigate the potential for SpaceCDNs which integrate CDN infrastructure directly within the LSNs, and show that this approach offers a promising alternative that decreases latencies by over 50%, making them comparable with the CDN experience of users behind terrestrial ISPs. Our aim is to stimulate further research and discussion on overcoming the challenges of effective content delivery with growing LSN offerings.

We propose XRC, an explicit rate control algorithm that overcomes the poor performance of commonly used TCP variants in cellular networks. XRC exploits explicit feedback from the radio access network that is aware of the physical, network and transport layer information of all UEs as well as resource distribution policies for users with different traffic characteristics. XRC co-exists fairly with other XRC and non-XRC flows at the wireless and non-wireless bottlenecks while it strictly controls queuing delay within a small threshold. We implement XRC in NS-3 and examine its performance across a range of network loads and dynamics. When competing with CUBIC at a wireless bottleneck, XRC achieves a Jain’s fairness index of 99.7% while providing a 3x lower median queuing delay compared to when CUBIC competes with CUBIC in the same setup.

LEO satellite "mega-constellations" such as SpaceX's Starlink, Amazon's Kuiper, OneWeb are launching thousands of satellites annually, promising high-bandwidth low-latency connectivity. To quantify the achievable performance of such providers, we carry out a measurement study of the spatial and temporal characteristics as well as the geographic variability of the connectivity provided by Starlink, the current leader in this space. We do this by building and deploying a browser extension that provides data about web performance seen by 28 users from 10 cities across the world. We complement this with performance tests run from three measurement nodes hosted by volunteer enthusiasts in the UK, EU and USA. Our findings suggest that although Starlink offers some of the best web performance figures among the ISPs observed, there are important sources of variability in performance such as weather conditions. The bent-pipe connection to a satellite and back to earth also forms a significant component of the observed latency. We also observe frequent and significant packet losses of up to 50% of packets, which appear to be correlated with handovers between satellites. This has an effect on achievable throughput even when using modern congestion control protocols such as BBR or CUBIC.

Today almost half the world's population does not have Internet access. This is particularly the case in rural and undeserved regions where providing Internet access infrastructure is challenging and expensive. To this end, we present demonstration of WhiteHaul [5], a low-cost hybrid cross-layer aggregation system for TV White Space (TVWS) based backhaul. WhiteHaul features a custom-designed frequency conversion substrate that efficiently handles multiple noncontiguous chunks of TVWS spectrum using multiple low-cost COTS 802.11n/ac cards but with a single antenna. At the software layer, WhiteHaul uses MPTCP as a link-level tunnel abstraction to efficiently aggregate multiple chunks of the TVWS spectrum via a novel uncoupled, cross-layer congestion control algorithm. This demo illustrates the unique features of the WhiteHaul system based on a prototype implementation employing a modified version of MPTCP Linux Kernel and a custom-designed conversion substrate. Using this prototype, we highlight the performance of the WhiteHaul system under various configurations and network conditions.

We address the challenge of backhaul connectivity for rural and developing regions, which is essential for universal fixed/mobile Internet access. To this end, we propose to exploit the TV white space (TVWS) spectrum for its attractive properties: low cost, abundance in under-served regions and favorable propagation characteristics. Specifically, we propose a system called WhiteHaul for the efficient aggregation of the TVWS spectrum tailored for the backhaul use case. At the core of WhiteHaul are two key innovations: (i) a TVWS conversion substrate that can efficiently handle multiple non-contiguous chunks of TVWS spectrum using multiple low cost 802.11n/ac cards but with a single antenna; (ii) novel use of MPTCP as a link-level tunnel abstraction and its use for efficiently aggregating multiple chunks of the TVWS spectrum via a novel uncoupled, cross-layer congestion control algorithm. Through extensive evaluations using a prototype implementation of WhiteHaul, we show that: (a) WhiteHaul can aggregate almost the whole of TV band with 3 interfaces and achieve nearly 600Mbps TCP throughput; (b) the WhiteHaul MPTCP congestion control algorithm provides an order of magnitude improvement over state of the art algorithms for typical TVWS backhaul links. We also present additional measurement and simulation based results to evaluate other aspects of the WhiteHaul design.

Mobile phones and innovative data oriented mobile services have the potential to bridge the digital divide in Internet access and have transformative developmental impact. However as things stand currently, economics come in the way for traditional mobile operators to reach out and provide high-end services to under-served regions. We propose a do-it-yourself (DIY) model for deploying mobile networks in such regions that is in the spirit of earlier community cellular networks but aimed at provisioning high-end (4G and beyond) mobile services. Our proposed model captures and incorporates some of the key trends underlying 5G mobile networks and look to expand their scope beyond urban areas to reach all by empowering small-scale local operators and communities to build and operate modern mobile networks themselves. We showcase a particular instance of the proposed deployment model through a trial deployment in rural UK to demonstrate its practical feasibility.

Although SDN is considered as one of the key technologies behind the impending 5G evolution of mobile networks, the opportunity of reaping its benefits is largely still untapped on the Radio Access Network (RAN) side due to the lack of a software-defined RAN (SD-RAN) platform. In this work we demonstrate the capabilities of FlexRAN, an open-source SD-RAN platform developed to fill this void. FlexRAN separates the RAN control and data planes with a custom-tailored southbound API. Besides it features a hierarchical control plane architecture that enables programmability, flexible and dynamic control function placement (allowing different degrees of coordination within and among base stations) and real-time control. Virtualized control functions and control delegation are two key features in FlexRAN that makes these capabilities possible. This demo illustrates the capabilities and the performance of FlexRAN based on a prototype implementation, while its applicability is highlighted through a Mobile Edge Computing use case, where it acts as an enabler of a video bitrate adaptation application based on the radio conditions at the network edge.

Although the radio access network (RAN) part of mobile networks offers a significant opportunity for benefiting from the use of SDN ideas, this opportunity is largely untapped due to the lack of a software-defined RAN (SD-RAN) platform. We fill this void with FlexRAN, a flexible and programmable SD-RAN platform that separates the RAN control and data planes through a new, custom-tailored southbound API. Aided by virtualized control functions and control delegation features, FlexRAN provides a flexible control plane designed with support for real-time RAN control applications, flexibility to realize various degrees of coordination among RAN infrastructure entities, and programmability to adapt control over time and easier evolution to the future following SDN/NFV principles. We implement FlexRAN as an extension to a modified version of the OpenAirInterface LTE platform, with evaluation results indicating the feasibility of using FlexRAN under the stringent time constraints posed by the RAN. To demonstrate the effectiveness of FlexRAN as an SD-RAN platform and highlight its applicability for a diverse set of use cases, we present three network services deployed over FlexRAN focusing on interference management, mobile edge computing and RAN sharing.

In this paper, we propose a dynamic decentralized scheme, namely, the Multi-Objective Harmony Search (MO-HS). The proposed scheme improves on the conventional single-objective HS scheme by attempting to optimize two objective functions simultaneously. In particular, the MO-HS scheme attempts to minimize the use of the same channels by edge users in neighboring cells, and the average cell interference. Simulation results demonstrate that, with a slight degradation in fairness, the proposed scheme achieves 21% throughput improvements to edge users as compared to the conventional HS without penalizing other users.

In this paper, we propose a new addressing scheme, namely, the Clock Skew Addressing (CLOSA) scheme, that allows for assigning a unique IPv6 addresses to each node in the Internet of Things (IoT) network. The CLOSA scheme eliminates the need for the inefficient techniques of duplicate address detection and allocation table validation used in most existing addressing schemes. CLOSA guarantees uniqueness by extracting the clock skew of each communication device and converting it into an IPv6 address. Simulation analysis confirms that the proposed scheme can provide significant reductions in communication overheads as compared to the well-known LEADS, SIPA, and DAD addressing schemes.