可编程网络数据平面技术进展

网络数据平面执行数据包处理转发,是网络性能的决定性因素之一。大带宽、低时延、可持续演进的网络基础设施需要构建高效可编程的网络数据平面。首先,介绍数据包处理转发模型,并以此为基础概述网络数据平面在性能与可编程性面临的关键挑战。然后,从数据包查找算法理论与软/硬件协同实现机制出发,详细论述其基本思路及关键核心技术进展以应对上述关键挑战。最后,探讨高效可编程数据平面的未来发展趋势与技术演进路线。     

基于OpenFlow的虚拟网实现研究

软件定义网络是一种数据和控制平面分离、软件可编程的新型网络架构及技术,控制平面使用以OpenFlow为代表的协议对转发平面进行集中式控制。SDN架构的这些特点能很好地满足了云计算对虚拟网络的集中化、标准化、自动化的配置管理要求。针对传统虚拟网络技术支持云计算平台的不足,提出基于OpenFlow的SDN技术设计虚拟网络的思路,论述了几种虚拟网络实现的原理与处理流程,并给出了模块化的软件设计及部分关键代码功能描述。     

面向全可编程网络数据平面的资源优化方法

现有数据平面无法在整体上支持网络功能的创新和演进,因此面向用户可编程的新型网络数据平面技术发展迅速.针对现有可编程数据平面硬件开销过大且缺乏资源优化的问题,从解析器、匹配表、动作执行器三个方面建立了资源开销模型,并分别提出了类型域合并、匹配域偏移量合并、"域-字"拆分合并映射等资源优化方法.基于NetFPGA的仿真结果表明,与现有机制相比,所提方法减小了38%左右的资源开销.     

同步无线Mesh网络数据包连发技术研究

现有的基于多方向天线阵列的同步无线Mesh网络在一个数据时隙内只发送一个数据包,这在发送节点采用高调制速率发送数据包时会造成时隙利用率的下降。针对该问题,对该网络下的数据包连发技术进行了研究,给出了最多可连发的数据包个数与计算时机、序列号与确认机制、涉及到的参量、父子节点处理流程的详细设计方案。理论性能对比结果表明,在发送节点采用高调制速率发送数据包时,在该网络下采用数据包连发技术能够大幅度提高时隙利用率,网络性能明显提升。     

汇聚网络和服务器统一计算架构的网络流处理器

NFP32xx系列网络流处理器采用65nm技术,由40个支持硬件多线程的可编程内核组成,运行频率达到1．4GHZ。320个硬件线程优化了存储器访问效率,可以提供每秒560亿次指令运算能力,如果以每秒处理3000万个数据包计算,将有1800条指令负责处理每一个数据包。     

软件定义网络中链路故障恢复机制研究

软定义网络(SDN)一种革新的网络架构,实现了控制平面和数据转发平面分离,开放了网络的可编程能力,简化了网络管理。随着SDN技术在现实中的广泛应用,其所存在的问题也凸显出来,链路故障就是其中的一个重要方面。文中针对SDN在链路故障方面存在的问题,通过对SDN技术特征和链路故障管理的分析,对现有的SDN中链路故障恢复方法进行了深入剖析,以期对未来在SDN中故障管理机制的研究提供参考。     

基于可编程数据平面的南向协议研究

由于传统网络设备固化且依赖于物理基础设施,难以适应智能化网络的需求。为提高网络的智能化,开放网络的可编程能力,软件定义网络和可编程数据平面应运而生。文章介绍了软件定义网络、可编程数据平面,及其所对应的南向协议,包括OpenFlow协议及其所存在的问题,P4Runtime协议的优势。然后用Mininet软件搭建了网络仿真对P4Runtime的优势进行验证。仿真实验表明,在可编程数据平面协议无关的基础上,P4Runtime作为控制平面和数据平面之间的南向协议,提供了基于Python的交互式和脚本两种下流表方式,与SDN传统下流表方式相比具有更高的灵活性和扩展性,更易于管理人员对网络进行统一管理。为运营商、数据中心等应用场景提供了新的控制管理方案。     

基于可编程硬件的有状态网络功能硬件加速架构

为了解决无状态加速器对有状态虚拟网络功能（Virtual Network Function,VNF）的加速效果较差的问题,该文提出了一种基于可编程硬件的有状态功能处理加速架构（Stateful Function Processing Acceleration Architecture,SFPA）.SFPA通过为数据平面提供有状态处理单元（Staeful Processing Unit,SPU）,将数据包处理任务卸载到数据平面上.此外,SFPA能够为多个VNF独立地分配加速资源,并采用资源分配优化算法降低硬件资源开销,提高了加速架构的灵活性.基于NetFPGA-10G平台的实验结果表明,SFPA架构下,VNF的吞吐量是采用DPDK加速时的2.9倍,是无状态硬件加速器的1.7倍;资源分配优化算法的优化率最高可达41.9%.     

基于SDN网络的防火墙系统设计与实现

软件定义网络（SDN）作为新的网络技术,能很好地满足现在对网络规模和性能的要求。为了进一步提升SDN网络的安全性,文章对SDN网络的防火墙系统进行了研究,利用控制平面与数据平面分离的特点,采用控制平面对网络集中进行实时监控与网络管理,在SDN控制器中实现数据包过滤与入侵监测,通过自定义数据转发和安全策略,实现集中式安全控制,最终实现网络安全性能提升。     

下一代网络的核心技术——网络处理器

网络应用的飞速发展和对线速的智能化处理的需求导致了网络处理器的出现。可编程的网络处理器不但提供了以线速处理数据包的高性能的硬件功能,同时还具备极大的系统灵活性。虽然当前的网络处理器的结构设计各不相同,随着网络技术的发展,网络处理器必将成为下一代网络的核心技术。结合当前的网络发展趋势,从现有的网络处理器的结构分析入手,论述了满足下一代网络应用需求的网络处理器应该具有的结构特点。     

应用于协议无感知转发交换机的流缓存方法

协议无感知转发支持任意协议的解析和处理,增强了软件定义网络的可编程能力。为提高转发性能,该文提出一种应用于协议无感知转发交换机的流缓存方法,通过识别匹配和动作的依赖关系,得到匹配字段的绝对位置,用以预先解析报文。为确保流缓存的加速效果,根据匹配类型与表项数量选择应用流缓存的流表。此外,该文对比了单流表缓存与多流表缓存对转发性能的提升,并提出了根据网络流量实际情况的自适应切换策略。通过扩展POFSwitch实现所提方法,并用实际规则与骨干网流量进行验证,应用流缓存后,交换机报文转发速率提升了220%。流缓存可以为可编程数据平面提供更高的转发性能。     

弹性协议可定制的网络数据平面结构及其映射算法

随着网络功能的不断扩展,新型网络协议的不断涌现,这些协议中的数据包具有新的格式定义,需要网络设备能够支持相应的解析和查找。软件定义网络(Software Defined Networking, SDN)基于流表的转发设计使得网络的创新变得简单,但是仍然难以支持任意协议的可编程解析和处理。该文联合考虑数据包的解析和查找过程,提出一种支持协议弹性定制的数据包查找硬件结构,通过比特粒度的解析和基于元操作的查找过程,使得任意协议能够在硬件结构上得到处理;此外,该文针对所提硬件结构提出一种基于多叉树的映射算法,将用户定制协议映射到硬件处理流水线和查找表中。通过实际的FPGA部署验证了所提结构能够支持多种协议的灵活定制,在硬件中的处理速度可以达到390 Gbps,与已有方案相比,其硬件资源利用率有明显降低。该结构对未来的软件定义网络的数据平面设计有重要的意义。     

Control-on-demand: an efficient approach to router programmability

Control-on-demand is a paradigm for network programmability at the network transport level. Prior work on active and programmable networking at this level either achieves flexibility by inserting significant software in the critical path of forwarding or achieves efficiency by sacrificing functionality and relegating programmability to connection management. In contrast, control-on-demand acts both in the control plane and in the data plane, still without adding software in the critical forwarding path. Rather than applying essential programs to every datagram, our approach is to apply the installed service logic asynchronously from data forwarding. This way we avoid essential processing in the critical forwarding path, applying the (user) installed service logic for service enhancement only. In this paper, we describe control-on-demand and how its service model provides sufficient richness to act in the data path. Set is restrictive enough to avoid the significant performance overhead of other in-data path approaches. The expressiveness of the programmable model is limited to observing and suggesting to the forwarding engine, but is never essential for correct processing, thus significantly reducing security and robustness concerns. Consequently, control-on-demand is efficient enough to make it viable for elementary services. Rather than replacing the interoperability layer, control-on-demand represents an evolution of router (switch) control functionality. As the required modification of router forwarding engines is insignificant, control-on-demand is viable in practice in the near future. These concepts have been prototyped as part of the Pronto Control Platform. In this paper, we describe our IPv6 router prototype implementation and discuss the application of control-on-demand on a number of interesting problems     

软件定义网络在电力数据通信网中的应用研究

软件定义网络（Software Defined Network,SDN）是一种全新的网络架构,它的设计理念是将网络的控制平面与数据转发平面分离,并实现可编程化控制.Openflow由美国斯坦福大学于2007年提出,它提供了标准化的接口,采用流表控制方式,将传统网络通信设备的数据转发和路由控制功能分离,是实现SDN的关键技术.从技术内涵、设备模型等方面对SDN进行了深入研究,同时研究了电力数据通信网的实际需求和现存问题,最后对软件定义网络在电力数据通信网中的应用进行了讨论.     

基于网络处理器的区分服务设计

网络处理器凭借其具有专用集成电路的高效分组转发特性以及通用处理器的灵活可编程性,成为推动下一代网络发展的核心技术。介绍了综合服务模型的包分类器和包调度器的特点,并在分析NP3网络处理器框架的基础上,采用基于多域的深度包处理设计和基于层次化的流调度设计,论述了利用NP3网络处理器实现了区分服务应用的设计。测试结果表明,该方案合理可行。     

Packet processing and data plane program verification: A survey with tools,techniques, and challenges

In today's era of fast-growing network-enabled devices combined, it increases the complexity of the network. This leads to the massive data packet transfer on the network via the data plane in a software-defined networking environment. The programmable packet processing in a data plane may introduce indirect bugs that are hard to catch manually. To avoid catastrophic after-effects, such programs need to be formally verified. Researchers have proposed various tools and techniques to verify the data plane program using the P4 language. Most of the researchers have used the concept of assertion and symbolic execution to provide P4 verification approaches. As symbolic execution does not scale up well, researchers have proposed different techniques, which include the use of constraints, slicing of the program, parallelization, data plane verification, program verification, and so on. The tools have experimented with different choices for compiler optimization. In this article, we perform a pervasive survey on various verification tools and techniques based on data plane programming using domain-specific language like P4 from the inception of the concept. We have compared the packet processing tools developed as per the requirement of time with their ideology and the impact of change.     

Features of PBB-TE Architecture and GMPLS Control Technology

Time Division Multiplexing (TDM) transport networks are evolving to packet-oriented, and a variety of carrier-class packet transport technologies have emerged. Provider Backbone Bridge with Traffic Engineering (PBB-TE) is a connection-oriented packet transport technology that provides good scalability and manageability, and guarantees Quality of Service (QoS). Generalized Multi-Protocol Label Switching (GMPLS) is a mature transport network control plane technology that supports multiple data planes with different switching granularity. GMPLS-controlled PBB-TE is a promising solution for Packet Transport Networks (PTN).     

Guest editorial special issue on computational intelligence in telecommunications networks and internet services-part III

A variety of detailed technologies, concepts, and models aim at the realization of intelligent integrated networks and services. Active and programmable networking enable the introduction of new network services by adding dynamic programmability to network devices and making aspects of the programmability accessible to third-party vendors and users via open interfaces. Open and programmable network elements help redefine network software architectures and move control and management systems away from traditional closed and rigid solutions, bringing us one step closer to an environment where all devices and services seamlessly interoperate and cooperate with each other. Computational intelligence (CI) has emerged through a vivid and diversified synergy of technologies of granular computing, neural networks, and evolutionary computing. Each of the contributing technologies there plays an important and unique role. In essence, we can state that CI is a manifestation and implementation of a general design methodology applied to complex systems. The article reviews this special issue.