Network Function Virtualization Platform Research Articles

On the Upgrade of Service Function Chains With Heterogeneous NFV Platforms

The fast development of high-performance and flexible SmartNICs and programmable data plane switches (PDP-SWs) has motivated people to consider the deployment of virtual network functions (vNFs) on them. Hence, together with traditional virtual machines (VMs), SmartNICs and PDP-SWs form heterogeneous network function virtualization (NFV) platforms for realizing vNF service chains (vNF-SCs). In this work, we consider the transition from software-based homogeneous NFV platforms to the heterogeneous ones, and study how to optimize the service upgrade of vNF-SCs. Specifically, the service upgrade is divided into two steps, which are 1) selecting servers/switches in the substrate network (SNT) to upgrade, which is done by adding SmartNICs to servers and replacing traditional switches with PDP-SWs, under a fixed budget, and 2) redeploying the existing vNF-SCs in the updated SNT to maximize the quality-of-service (QoS) improvement on latency reductions. We first formulate an integer linear programming (ILP) model to optimize the overall service upgrade, then design two correlated optimizations for its two steps, and finally propose polynomial-time approximation algorithms to solve the optimizations. The results of extensive simulations confirm that our proposed algorithm outperforms the existing benchmarks in various network scenarios, and achieves better tradeoff between performance and time-efficiency.

NFV Platforms: Taxonomy, Design Choices and Future Challenges

Due to the intrinsically inefficient service provisioning in traditional networks, Network Function Virtualization (NFV) keeps gaining attention from both industry and academia. By replacing the purpose-built, expensive, proprietary network equipment with software network functions consolidated on commodity hardware, NFV envisions a shift towards a more agile and open service provisioning paradigm with much lower capital expenditure (CapEx) and operational expenditure (OpEx). Nonetheless, just like any complex system, NFV platforms commonly consist of abounding software and hardware components and usually incorporate disparate design choices based on distinct motivations or use cases. This broad collection of convoluted alternatives makes it extremely arduous for network operators to make proper choices. Although numerous efforts have been devoted to investigating different aspects of NFV, none of them specifically focused on NFV platforms or attempted to explore the design space. In this paper, we present a comprehensive survey on NFV platform design. Our study solely targets existing NFV platform implementations. We begin with an architectural view of the standard reference NFV platform and present our taxonomy of existing NFV platforms based on the principal purpose of design. Then we thoroughly explore the design space and elaborate on the implementation choices each platform opts for. We believe that our study gives a detailed guideline for network operators or service providers to choose or implement the most appropriate NFV platforms based on their respective requirements. Note that this report serves as a complementary document for a published IEEE TNSM paper [1]. We will periodically update this document to include the newly proposed NFV platforms and design choices.

Application-Driven Provisioning of Service Function Chains Over Heterogeneous NFV Platforms

Although network function virtualization (NFV) has been proven to be beneficial in terms of equipment cost, service delivery flexibility, and time-to-market, most of the studies in this area only addressed homogeneous NFV platforms (e.g., with virtual machines (VMs) only). In this work, we argue that by leveraging heterogeneous NFV platforms such as VMs, docker containers, and programmable hardware accelerators (e.g., SmartNICs), one could achieve better flexibility and cost-effectiveness to support virtual network function service chains (vNF-SCs) with various quality-of-service (QoS) requirements. Therefore, we study application-driven provisioning of vNF-SCs over heterogeneous NFV platforms, and design a polynomial-time approximation algorithm to tackle the problem for near-optimal solutions. We first introduce a layered auxiliary graph (LAG) based approach to model the problem of vNF-SC provisioning, and then formulate a novel integer linear programming (ILP) model based on it. Specifically, the ILP model minimizes the total cost of vNF-SC deployment while ensuring that the QoS requirements of all the vNF-SCs are satisfied. To solve the ILP time-efficiently, we propose an approximation algorithm based on linear programming (LP) relaxation and randomized rounding. Extensive simulations confirm that with significantly improved time-efficiency, our proposed algorithm can provide near-optimal solutions whose gaps to the exact ones are bounded.

CoNFV

Network function virtualization (NFV) is a powerful networking approach that leverages computing resources to perform a time-varying set of network processing functions. Although microprocessors can be used for this purpose, their performance limitations and lack of specialization present implementation challenges. In this article, we describe a new heterogeneous hardware-software NFV platform called CoNFV that provides scalability and programmability while supporting significant hardware-level parallelism and reconfiguration. Our computing platform takes advantage of both field-programmable gate arrays (FPGAs) and microprocessors to implement numerous virtual network functions (VNF) that can be dynamically customized to specific network flow needs. The most distinctive feature of our system is the use of global network state to coordinate NFV operations. Traffic management and hardware reconfiguration functions are performed by a global coordinator that allows for the rapid sharing of network function states and continuous evaluation of network function needs. With the help of state sharing mechanism offered by the coordinator, customer-defined VNF instances can be easily migrated between heterogeneous middleboxes as the network environment changes. A resource allocation and scheduling algorithm dynamically assesses resource deployments as network flows and conditions are updated. We show that our deployment algorithm can successfully reallocate FPGA and microprocessor resources in a fraction of a second in response to changes in network flow capacity and network security threats including intrusion.

A Multi-Site NFV Testbed for Experimentation With SUAV-Based 5G Vertical Services

With the advent of 5G technologies, vertical markets have been placed at the forefront, as fundamental drivers and adopters of technical developments and new business models. Small Unmanned Aerial Vehicles (SUAVs) are gaining traction in multiple vertical sectors, as key assets to generate, process, and distribute relevant information for the provision of value-added services. However, the enormous potential of SUAVs to support a flexible, rapid, and cost-effective deployment of vertical applications is still to be exploited. In this paper, we leverage our prior work on Network Functions Virtualization (NFV) and SUAVs to design and build a multi-site experimentation testbed based on open-source technologies. The goal of this testbed is to explore synergies among NFV, SUAVs, and vertical services, following a practical approach primarily governed by experimentation. To verify our testbed design, we realized a reference use case where a number of SUAVs, cloud infrastructures, and communication protocols are used to provide a multi-site vertical service. Our experimentation results suggest the potential of NFV and SUAVs to flexibly support vertical services. The lessons learned have served to identify missing elements in our NFV platform, as well as challenging aspects for potential improvement. These include the development of specific mechanisms to limit processing load and delays of service deployment operations.

Re-Architecting NFV Ecosystem with Microservices: State of the Art and Research Challenges

Network Function Virtualization (NFV), considered a key enabler of network softwarization, promises to reduce capital and operational expenditures for network operators by moving packet processing from purpose-built hardware to software running on commodity servers. However, the state-of-the-art in NFV is merely replacing monolithic hardware with monolithic VNFs, the software that realizes different network functions (e.g., firewalls, WAN optimizers, and so on). Although this is a first step toward deploying NFV, common functionality is repeatedly implemented in monolithic VNFs. Repeated execution of such redundant functionality introduces processing overhead when VNFs are chained to realize Service Function Chains and leads to sub-optimal usage of infrastructure resources. This stresses the need for re-architecting the NFV ecosystem, from VNFs to their orchestration, through modular VNF design and flexible service composition. In that perspective, we make the case for using the microservice software architecture, proven to be effective for building large-scale cloud applications from reusable and independently deployable components, to re-architect the NFV ecosystem. We also discuss the state-of-the-art in realizing modular VNFs from both industry and academia. Finally, we outline a set of research challenges for microservice-based NFV platforms.

Shared Virtual Function Orchestration Technique

Network function virtualization (NFV) is a promising technique of high quality, flexible and scalable service for telecommunication companies clients and for enterprise data center clients. One of the important capabilities of this technique is providing a virtual service as a combination of multiple virtual functions. There are two types of virtual functions: those intended for a single customer (su-VF) and those that can serve multiple users (mu-VF). In case when output of mu-VF is chained with inputs of several different su-VFs, there is a need for a mechanism of identification and separation of users network flows passing through mu-VF to allocate them correctly between inputs of su-VFs in the NFV infrastructure. In the cloud environment, it is not always possible to use VLAN tags, IP and MAC addresses for that. In this paper, we consider the problem of identification of network traffic coming from a certain user inside an NFV platform and present a solution implemented in C2 MANO-platform.

Network Function Virtualization-Aware Orchestrator for Service Function Chaining Placement in the Cloud

Network function virtualization (NFV) has been introduced by network service providers to overcome various challenges that hinder them from satisfying the growing demand for networking services with higher return-on-investment. The association of NFV with the leading technologies of information technology virtualization and software defined networking is paving the way for flexible and dynamic orchestration of the VNFs, but still, various challenges need to be addressed. The VNFs instantiation and placement problems on data center’s (DC) servers are key enablers to achieve the desired flexible and dynamic NFV applications. In this paper, we have addressed the VNF placement problem by providing a novel mixed integer linear programming (MILP) optimization model and a novel heuristic solution, Betweenness centrality Algorithm for Component Orchestration of NFV platform (BACON), for small- and large-scale DC networks. The proposed solution addresses the VNF placement while taking into consideration the carrier-grade nature of the NFV applications and at the same time, minimizing the intra- and end-to-end delays of the service function chain (SFC). Also, the proposed approach enhances the reliability and the quality of service (QoS) of the SFC by maximizing the count of the functional group members. To evaluate the performance of the proposed solution, this paper conducts a comparative analysis with an NFV-agnostic algorithm and a greedy-k-NFV approach, which is proposed in the literature work. Also, this paper defines the complexity and the order of magnitude of the MILP model and BACON. BACON outperforms the greedy algorithms especially the greedy-k-NFV solution and has a lower complexity, which is calculated as $O((n^{3}-n^{2})/2)$ . The simulation results show that finding an optimized VNF placement can achieve minimal SFCs delays and enhance the QoS accordingly.

Multi-Provider and Multi-Domain Resource Orchestration in Network Functions Virtualization

Resource orchestration has a major impact on improving the performance of network services and reducing the system cost composed of both capital expenditures and operational expenses in network functions virtualization (NFV). In this paper, we consider the optimal resource orchestration problem in a multi-domain NFV system under the competition among multiple NFV service providers (NSPs). In particular, we analyze a game on an NFV platform where an NSP can reserve different types of resources, including the virtual computing, storage, and network resources, and the non-virtualized resources allocated by various NFV domains, for optimizing the utility in an individual manner. We also derive a necessary and sufficient condition for equilibrium under the competition among NSPs. We further investigate the equilibrium in a scenario of cooperation where NSPs build their own NFV infrastructure and join together to create a federation. Our numerical results illustrate the best response in resource reservation of a provider with respect to the strategy of other providers and the effect of the number of domains on the utility obtained by NSPs in the competition. Importantly, we demonstrate that an NSP is able to make a profit when the number of domains in an NFV infrastructure increases until a threshold, beyond which the utility of an NFV provider falls down, which is useful for designing a multi-domain NFV platform, especially in a multi-provider scenario. Another observation is that the best strategy of the NSPs in the competition is opposite to that in the scenario of cooperation, which is significant for the NSPs in the optimization of their utility.

Real-time network function virtualization with timing interfaces

More and more infrastructure is becoming virtualized. Recently this trend has begun to include network functions - such as firewalls, WAN optimizers, and intrusion prevention systems - that have traditionally been implemented as middleboxes using dedicated hardware. This trend towards network function virtualization (NFV) offers a variety of potential benefits that resemble those of cloud computing, including consolidation, easier management, higher efficiency, and better scalability. However, current cloud technology is not a perfect match for NFV workloads: since the infrastructure is shared, the time it takes for a packet to pass through a particular function is no longer predictable, and can in fact vary considerably. This is causing headaches for operators, who can no longer treat network functions as "bumps in the wire" and must now consider a complex web of possible interactions and cross-talk when operating or diagnosing their systems. In this position paper, we propose a compositional approach towards building a scalable NFV platform that can provide latency and throughput guarantees using timing interfaces. We discuss our preliminary results that leverage and extend recent advances on timing interfaces and compositional theory from the real-time systems domain to the NFV setting, and we highlight open challenges and potential directions towards real-time NFV.

Towards "Full Containerization" in Containerized Network Function Virtualization

With exploding traffic stuffing existing network infra-structure, today's telecommunication and cloud service providers resort to Network Function Virtualization (NFV) for greater agility and economics. Pioneer service provider such as AT&T proposes to adopt container in NFV to achieve shorter Virtualized Network Function (VNF) provisioning time and better runtime performance. However, we characterize typical NFV work-loads on the containers and find that the performance is unsatisfactory. We observe that the shared host OS net-work stack is the main bottleneck, where the traffic flow processing involves a large amount of intermediate memory buffers and results in significant last level cache pollution. Existing OS memory allocation policies fail to exploit the locality and data sharing information among buffers. In this paper, we propose NetContainer, a software framework that achieves fine-grained hardware resource management for containerized NFV platform. NetContainer employs a cache access overheads guided page coloring scheme to coordinately address the inter-flow cache access overheads and intra-flow cache access overheads. It maps the memory buffer pages that manifest low cache access overheads (across a flow or among the flows) to the same last level cache partition. NetContainer exploits a footprint theory based method to estimate the cache access overheads and a Min-Cost Max-Flow model to guide the memory buffer mappings. We implement the NetContainer in Linux kernel and extensively evaluate it with real NFV workloads. Exper-imental results show that NetContainer outperforms conventional page coloring-based memory allocator by 48% in terms of successful call rate.

Towards "Full Containerization" in Containerized Network Function Virtualization

With exploding traffic stuffing existing network infra-structure, today's telecommunication and cloud service providers resort to Network Function Virtualization (NFV) for greater agility and economics. Pioneer service provider such as AT&T proposes to adopt container in NFV to achieve shorter Virtualized Network Function (VNF) provisioning time and better runtime performance. However, we characterize typical NFV work-loads on the containers and find that the performance is unsatisfactory. We observe that the shared host OS net-work stack is the main bottleneck, where the traffic flow processing involves a large amount of intermediate memory buffers and results in significant last level cache pollution. Existing OS memory allocation policies fail to exploit the locality and data sharing information among buffers. In this paper, we propose NetContainer, a software framework that achieves fine-grained hardware resource management for containerized NFV platform. NetContainer employs a cache access overheads guided page coloring scheme to coordinately address the inter-flow cache access overheads and intra-flow cache access overheads. It maps the memory buffer pages that manifest low cache access overheads (across a flow or among the flows) to the same last level cache partition. NetContainer exploits a footprint theory based method to estimate the cache access overheads and a Min-Cost Max-Flow model to guide the memory buffer mappings. We implement the NetContainer in Linux kernel and extensively evaluate it with real NFV workloads. Exper-imental results show that NetContainer outperforms conventional page coloring-based memory allocator by 48% in terms of successful call rate.

Toward High-Performance and Scalable Network Functions Virtualization

Network functions virtualization (NFV) promises to bring significant flexibility and cost savings to networking. These improvements are predicated on being able to run many virtualized network elements on a server, which leads to a fundamental question on how scalable an NFV platform can be. With this in mind, the authors build an experimental platform with commonly used NFV technologies. They evaluate the NFVs performance and scalability and, based on their demonstrated improvements, discuss best practices for achieving optimum NFV performance on commodity hardware. They also reveal the limitations on NFV scalability and propose a new architecture to address them.