Supporting ubiquitous deployment of built-in Internet service with Software Defined Networking (SDN), Network Function Virtualization (NFV), and Low Earth Orbit (LEO) satellite constellations has been widely accepted as one of the key technologies for the next-generation communication services. By integrating terrestrial and space network capabilities, new design features are introduced to existing network ecosystems. For instance, terrestrial Virtual Network Functions (VNFs) can now be hosted on satellites, utilizing satellite highways. This requires expanding the roles of the control units, originally responsible for terrestrial data planes, to include space-based counterparts. As a result, seamless integration of Service Function Chains (SFCs) across satellite constellations and terrestrial control units becomes a challenge due to the topology dynamics caused by high-speed LEO satellites. In this paper, we propose the Geosynchronous Service Function Chaining (GSFC) scheme to facilitate programmable, Internet SFC operations based on LEO satellite network environments. The key idea is to cluster adjacent LEO satellites to represent logical VNF containers at the fixed positions, where the initial VNFs at the region are continuously filled up by the traversing satellite payload functions in a predictable manner. With this design, the ground-based controllers can maintain the space-terrestrial SFCs without being affected by the constantly shifting satellite VNFs, and thereby large-scale and complex recalculation for the routing policies is avoided. The design principle introduces a ground-breaking approach to space Internet protocol stacks, facilitating robust routing for SFC operations across integrated space and terrestrial networks. Our simulation results verify the feasibility of the proposed GSFC-based VNF orchestration mechanism and reveal the trade-offs in both data and control plane performance.

Integrating Low Earth Orbit (LEO) satellites with terrestrial network infrastructures to support ubiquitous Internet service coverage has recently received increasing research momentum. One fundamental challenge is the frequent topology change caused by the constellation behaviour of LEO satellites. In the context of Software Defined Networking (SDN), the controller function that is originally required to control the conventional data plane fulfilled by terrestrial SDN switches will need to expand its responsibility to cover their counterparts in the space, namely LEO satellites that are used for data forwarding. As such, seamless integration of the fixed control plane on the ground and the mobile data plane fulfilled by constellation LEO satellites will become a distinct challenge. For the very first time in the literature, we propose in this paper the Virtual Data-Plane Addressing (VDPA) scheme by leveraging IP addresses to represent virtual switches at the fixed space locations which are periodically instantiated by the nested LEO satellites traversing them in a predictable manner. With such a scheme the changing data-plane network topology incurred by LEO satellite constellations can be made completely agnostic to the control plane on the ground, thus enabling a native approach to supporting seamless communication between the two planes. Our simulation results prove the superiority of the proposed VDPA based flow rule manipulation mechanism in terms of control plane performance.

Integrating Low Earth Orbit (LEO) satellites with terrestrial network infrastructures to support ubiquitous Internet service coverage has recently received increasing research momentum. One distinct challenge is the frequent topology change caused by the constellation behaviour of LEO satellites. In the context of software defined networking (SDN), the controller function that is originally required to control the conventional data plane fulfilled by terrestrial SDN switches will need to expand its responsibility to cover their counterparts in the space, namely LEO satellites that are used for data forwarding. As such, seamless integration of the fixed control plane on the ground and the mobile data plane fulfilled by constellation LEO satellites will become a distinct challenge. In this paper, we propose the Virtual Data-Plane Addressing (VDPA) Scheme by leveraging IP addresses to represent virtual switches at the fixed space locations which are periodically instantiated by the nested LEO satellites traversing them in a predictable manner. With such a scheme the changing data-plane network topology incurred by LEO satellite constellation can be made completely agnostic to the control plane on the ground, thus enabling a native approach to supporting seamless communication between the two planes. Our testbed-based experiment results prove the technical feasibility of the proposed VDPA-based flow rule manipulation mechanism in terms of data plane performance.

The launch of the StarLink Project has recently stimulated a new wave of research on integrating Low Earth Orbit (LEO) satellite networks with the terrestrial Internet infrastructure. In this context, one distinct technical challenge to be tackled is the frequent topology change caused by the constellation behaviour of LEO satellites. Frequent change of the peering IP connection between the space and terrestrial Autonomous Systems (ASes) inevitably disrupts the Border Gateway Protocol (BGP) routing stability at the network boundaries which can be further propagated into the internal routing infrastructures within ASes. To tackle this problem, we introduce the Geosynchronous Network Grid Addressing (GNGA) scheme by decoupling IP addresses from physical network elements such as a LEO satellite. Specifically, according to the density of LEO satellites on the orbits, the IP addresses are allocated to a number of stationary "grids" in the sky and dynamically bound to the interfaces of the specific satellites moving into the grids along time. Such a scheme allows static peering connection between a terrestrial BGP speaker and a fixed external BGP (e-BGP) peer in the space, and hence is able to circumvent the exposure of routing disruptions to the legacy terrestrial ASes. This work-in-progress specifically addresses a number of fundamental technical issues pertaining to the design of the GNGA scheme.

Empowered by computing at the network edge, data sensed from Internet of Things (IoT) devices can be processed by various IoT applications stored in the nearby cloudlets to reduce the response time between the IoT devices. Together with the recently wide- studied network slicing and Network Function Virtualization (NFV) paradigm, IoT edge computing function can satisfy the individual requirements on the flexibility, security as well as accessibility of the IoT applications. Although the significant research effort made on NFV architectures has received remarkable achievements recently, seldom work has put its emphasis on optimizing IoT edge computing when considering it as a service chain. Since edge computing is regarded to play as a critical role in the context of IoT paradigm to enhance network efficiency, we consider in this paper the dynamic VNF service chain allocating optimization for IoT edge computing. To this end, we detail an Integer Linear Programming (ILP) framework designed to VNF based IoT edge-chains and propose a heuristic scheme to reduce the computation difficulty for large size problems. At last, the attainable system performance of the proposed scheme has been validated by a wide set of investigations.

The explosive growth of mobile data traffic and the envisioned delay sensitive applications in 5G networks ranging from high definition video streaming with strict playout deadlines to multi modal tactile/haptic with kinaesthetic feedback that require some form of edge cloud cache support makes mobility a challenge. In this paper, we propose a Proactive Caching with Delay Guarantees (PCDG) approach to enhance the supporting of seamless mobility within 5G networks that are Information-Centric Networking (ICN)-aware. The proposed scheme is designed to cache contents into a set of potential edge clouds with delay guarantees and to achieve a trade-off among caching, redirection and missing cost. In particular, this approach consider the delay constraints in mobile network, especially the queuing delay in network links and edge clouds, which are modeled as M/M/1 and M/M/c queuing systems respectively. We formulate and linearize this problem as a Mixed Integer Linear Programming (MILP) model and compare the performance with other techniques. The result obtained from simulation reveal that the proposed PCDG scheme lead to a significantly lower total cost and higher satisfied probability albeit higher computational/complexity cost.

In emergency medical services, the lag time between injury and treatment is one of the most critical parameters with respect to patient survivability. Ambulance services aim to maximize the likelihood of prompt medical treatment to prevent death and/or potential non-reversible damages. The emerging Tactile Internet has a vital role to play on that frontier by allowing next generation of ambulances to be equipped with advanced haptic/tactile devices to allow pre-hospital treatment/diagnosis or even remote surgery while en route. In this paper we propose a novel reliable multi-modal e- health high mobility service optimization framework for ambulances utilizing mobile edge clouds to efficiently transport real time patient information to the hospital. The main challenge of the proposed e-health service is to guarantee the heterogeneous QoS requirements of all involved data flows between the ambulance and the medical personnel. To this end, we formulate the service configuration problem as an optimization problem. In addition, a set of low- complexity algorithms are proposed to provide competitive solutions in real-time. A comprehensive set of numerical investigations are presented to characterize the attainable system performance of the proposed schemes.

Notwithstanding the significant attention that network function virtualization architectures received over the last few years, little attention has been placed on cases where proactive caching is considered within a service chain. Caching algorithms have been developed independently from virtual network function (VNF) chaining schemes, and as we explain in detail in this paper such operation might lead to sub-optimal overall network and service performance. Since caching of popular content is envisioned to be one of the key adopted technologies in emerging 5G networks to increase network efficiency and overall end user perceived quality of service, we explicitly consider the interplay and subsequent optimization of caching-based VNF service chains. To this end, a mathematical programming framework is proposed tailored to VNF caching chains and, in addition, we detail a scale-free heuristic algorithm to provide competitive solutions for large network instances since the problem itself can be seen as a variant of the classical NP-hard uncapacitated facility location problem. A wide set of numerical investigations is presented for characterizing the attainable system performance of the proposed schemes.

Information-Centric Networking (ICN) or Content-Centric Networking (CCN), as it also known for, has recently been proposed as an evolutionary framework to propel the current Internet network architecture towards a content oriented design. Mobility-aware caching can be deemed as indispensable for improving the experience of mobile users. To this end, we propose a proactive caching with redirection (PCWR) approach for enhancing the support of seamless mobility within ICN networks as well as the Quality of Service (QoS). To achieve that, we model and formulate the underlying problem as an Integer Linear Programming (ILP) problem aiming to derive the optimal balance between content caching and redirection. Via a wide set of numerical investigations, we compare the proposed scheme with various previously defined caching schemes in order to explore the inherent trade-offs. The results reveal that the proposed framework lead to significant gains in network cost compare to other techniques. Moreover, the investigations shed further light into how network cost gain is impacted by the proportion of caching and redirection cost.