在空间通信中应用IP技术的研究现状

目前的CCSDS建议在动态路由选择、与地面因特网的互操作等方面不能完全满足空间探索对空间通信协议的要求,在空间通信中应用IP技术及其在安全、移动方面的扩展技术或许是解决途径之一。总结了美国航空航天局哥达德航天中心和喷气动力实验室研究在空间通信中应用IP技术的要求。对所涉及的关键问题进行了初步探讨。     

IP OVER CCSDS协议网关设计

随着我国载人航天、深空探测等领域的发展,空间传输网络与地面传输网络的融合已经越来越紧密。针对地面网络IP协议与空间网络CCSDS AOS协议转换设备的迫切需求,在以太网接口芯片和FPGA TEMAC接口IP内核的基础上进行设计,提出了一种IP协议与CCSDS AOS协议转换设计方案。采用该方案实现的设备已经进行了试验和验证,结果表明,IP OVER CCSDS协议网关达到了设计指标要求,可在基于IP业务的天-地传输系统中推广使用。     

移动IP技术分析

移动IPv4是基于网络层的移动管理协议,无论从位置管理还是移动切换管理都采用基于网络层IP来实现。作为支持宏观移动的技术,移动IP可以与微观移动的技术,如蜂窝IP等相结合应用。本文着重介绍移动IPv4技术的基本原理,同时从安全、路由和网络层的移动切换的角度,引入相关的补充技术,如安全认证机制、路由优化技术和平滑切换技术,提供完善的移动IP实现。     

移动IP技术分析

移动IPv4是基于网络层的移动管理协议，无论从位置管理还是移动切换管理都采用基于网络层IP来实现。作为支持宏观移动的技术，移动IP可以与微观移动的技术，如蜂窝IP等相结合应用。本着重介绍移动IPv4技术的基本原理，同时从安全、路由和网络层的移动切换的角度，引入相关的补充技术，如安全认证机制、路由优化技术和平滑切换技术，提供完善的移动IP实现。     

MPLS技术及标准化进展

多协议标记交换(MPLS)技术作为一种新兴的路由交换技术，越来越受到业界的关注。MPLS技术是结合二层交换和三层路由的L2／L3集成数据传输技术，它不仅支持网络层的多种协议，还可以兼容第二层上的多种链路层技术。采用MPLS技术的IP路由器以及ATM、FR交换机统称为标记交换路由器(LSR)，使用LSR的网络相对简化了网络层复杂度，兼容现有的主流网络技术，降低了网络升级的成本。此外，业界还普遍看好用MPLS提供VPN服务，实现负载均衡的网络流量工程。     

CCSDS空间链路协议体系分析

在CCSDS空间链路层协议上传递IP数据报,实现空间网络和地面网络的无缝连接是未来空地通信发展的主要方向。本文以CCSDS空间链路协议的发展为出发点,分别介绍了常规在轨系统（COS）空间链路协议、高级在轨系统（AOS）空间链路协议和邻近-1（prox-1）空间链路协议的业务类型和功能,分析了协议的层结构、基本原理和关键技术,并对我国开展相关研究提出了建议。     

Packet Design驾驭3层路由 提供更为先进的流量管理系统

随着网络应用深入生活,网络技术飞速发展,IP网络已经成为网络基础架构,具有无可比拟的优势。宽带IP网络是一种动态的、智能的网络,目前的大型网络都采用路由技术。然而,动态路由也带来了许多新的挑战,在采用动态路由协议的网络中,是路由协议自动地为所 有流量做出路径选择。     

IPsecVPN的设计

互联网上构筑应用系统已成为必然趋势。IP VPN可以通过开放的IP网络建立私有数据传输通道,将远程的分支办公室、商业伙伴、移动办公人员等连接起来,因此基于IP的VPN业务有很大的增长空间。但是,传统的IPv4协议不能满足对IP网络应用安全性的要求,IPsec隧道协议的出现为IPVPN提供了安全保障。《IPsec VPN的设计》一文针对IPsec VPN网络设计中的动态路由选择和网络地址转换问题,给出了北电网络的Contivity解决方案,这对电信运营商和网络规划设计人员有着一定的参考价值。     

CCSDS与TCP/IP协议转换的研究与实现

随着低轨卫星星座、载人航天工程和空间应用等领域的发展,空间传输网络和地面传输网络的融合已成为天地一体化网络发展的必然趋势。针对空间基于CCSDS(国际空间数据系统咨询委员会)链路协议的IP网络和地面IP网络之间的转换问题,文章提出一种协议网关的设计方案。该网关采用灵活的多线程结构和分层次分模块的架构实现CCSDS标准和TCP/IP(传输控制协议/网际协议)间的转换,利用ARP(地址解析协议)欺骗技术解决UDP(用户数据报协议)/TCP通信问题,实现终端通过低轨卫星的中继进行网络服务。最后给出了该网关的实现流程和性能测试结果。     

数据中继卫星系统的数据传输协议研究

首先介绍了美国中继卫星系统的基本概况,给出了其系统组成框图和连接关系,依据中继卫星系统数据传输任务和数据传输需求,并在分析比较ESA和CCSDS的星地数据传输管理协议的基础上,提出了使用CCSDS组织的AOS建议书作为数据中继卫星系统的数据传输协议建议,给出了数据传输帧的定义和初步操作建议。     

Space link simulator for development of new packet-based space communication protocols

Terrestrial network-based file transfer protocol is known to be unacceptable for the space network environment. The Consultative Committee for Space Data Systems (CCSDS) is about to propose a new file transfer protocol for use in both space and ground-based networks, named CCSDS File Delivery Protocol (CFDP). CFDP is based on packet oriented protocols as its underlaying network layer. The supported packet protocols include CCSDS packet standard protocol and TCP/IP. The space communication link displays specific characteristics different from those of terrestrial ones: larger link delay, higher bit error rates, bursts of errors, packet deordering, etc. For use in CFDP implementation, a packet protocol-based space link simulator is designed and implemented. This space link simulator, named LinkSim, can simulate not only distance driven link delay, but also link quality and link diversity. This paper presents the organization of the space link simulator and the algorithms used to emulate each link characteristic feature. The test shows that the LinkSim program simulates exactly the expected space link environment. An example configuration is also discussed at the end of this paper. Copyright © 1999 John Wiley & Sons, Ltd.     

Energy-Efficient Routing for Frequency-Hop Wireless Networks

The use of adaptive-transmission protocols in wireless, store-and-forward, packet communication networks may result in large differences in the energy requirements of the alternative paths that are available to the routing protocol. Routing metrics can provide quantitative measures of the quality and energy efficiency of the paths from the source to the destination. Such measures are required if the routing protocol is to take advantage of the potential energy savings that are made possible by an adaptive-transmission protocol. An energy-efficient protocol suite for routing and adaptive transmission in frequency-hop wireless networks is described and evaluated, several routing metrics are compared, and tradeoffs among energy efficiency, delay, and packet success probability are investigated.     

Single-packet IP traceback

The design of the IP protocol makes it difficult to reliably identify the originator of an IP packet. Even in the absence of any deliberate attempt to disguise a packet's origin, widespread packet forwarding techniques such as NAT and encapsulation may obscure the packet's true source. Techniques have been developed to determine the source of large packet flows, but, to date, no system has been presented to track individual packets in an efficient, scalable fashion. We present a hash-based technique for IP traceback that generates audit trails for traffic within the network, and can trace the origin of a single IP packet delivered by the network in the recent past. We demonstrate that the system is effective, space efficient (requiring approximately 0.5% of the link capacity per unit time in storage), and implementable in current or next-generation routing hardware. We present both analytic and simulation results showing the system's effectiveness.     

CCSDS遥控协议数据认证保护研究

针对CCSDS体制中分包遥控(Telecommand)系统所面临的安全威胁,结合空间通信环境的特点,总结了对遥控协议数据进行认证性保护的技术方法,讨论了认证算法在分包遥控协议中的应用位置。为了避免认证算法与COP-1闭环之间的冲突,提出了在数据链路层COP-1闭环之前进行认证操作的方法。结合国内外相关领域的研究进展,分析了在分包遥控协议中应用SHA-256进行数据认证性保护的必要性与可用性。     

A terminal-assisted route optimized NEMO management

The NEMO basic support protocol enhances mobile IPv6 (MIPv6) to enable mobile router (MR) to move together with mobile network node (MNN) as a unit. This protocol suffers from pinball routing effect which has triggered research works to enable direct routing between MNNs in the presence of network mobility. Instead of relying on MIPv6, this paper describes network mobility using a novel terminal-assisted IP mobility protocol on MNNs that work cooperatively with MRs and access routers to provide seamless connectivity. This protocol is superior as it neither suffers from pinball routing effect nor requires dedicated infrastructure support such as home agent. It also eliminates the need to dynamically increase the size of IP header in IP tunneling. Through quantitative comparisons with existing protocol, we show that this protocol performs better than existing protocols in terms of average packet delivery overhead and packet generation.     

CCSDS Advanced Orbiting Systems: international data communicationsstandards for the space station Freedom

Established in 1982, the Consultative Committee for Space Data Systems (CCSDS) is an international organization that is staffed by data-handling experts from nearly all of the world's major space agencies. Its goal is to develop standard data-communications techniques so that several agencies may cross-support each other's data flow and thus allow complex, international missions to be flown. Under the general umbrella of Advanced Orbiting Systems (AOS), an international CCSDS task force was formed in 1985 to develop standard data-communications concepts for manned missions, such as the space station Freedom and the Hermes space plane, and large unmanned vehicles, such as polar orbiting platforms. The history of the CCSDS and the development of the AOS recommendation are reviewed, and the user services and protocols embodied in its systems architecture are introduced     

软件定义无人机自组网高效自适应路由维护机制

为解决软件定义无人机自组网路由维护存在的控制开销和数据包延迟偏大的问题,基于现有的OpenFlow协议提出了一种高效自适应的软件定义无人机自组网路由维护机制( Efficient and Adaptive Software-defined Unmanned Aerial Vehicle Ad Hoc Network R...     

认证加密算法在CCSDS遥控协议中的应用研究

针对CCSDS分包遥控(Telecommand)系统所面临的安全威胁,结合空间通信环境的特点,通过对各种认证加密算法(AEAD)的性能分析,提出将GCM(Galois/Counter Mode)认证加密算法应用于分包遥控系统数据链路层的方案。设计并实现了基于OPNET的CCSDS分包遥控系统仿真框架。仿真结果表明,在不影响吞吐量性能的前提下,GCM认证加密算法能有效地保证分包遥控数据的机密性、完整性和信息来源的合法性,并且具有数据处理性能高、系统开销小的特点。     

MPLS-Linux体系结构及交换路由性能分析

本文详细介绍了MPLS-Linux的体系结构、核心数据结构、标签交换过程和QoS运行等实现技术，通过对MPLS-Linux组成的交换路由系统进行性能测试和分析，发现：在链路轻载或预留带宽的情况下，交换路由系统对数据流的服务质量优于传统路由系统；只有综合应用策略路由、数据报分类调度和标签交换才能实现Internet环境下对端到端服务质量的控制。     

Packet sequencing: a deterministic protocol for QoS in IP networks

We describe a deterministic protocol for routing delay and loss-sensitive traffic through an IP network. Unlike traditional approaches, the method described here - packet sequencing - does not rely on queue management. Instead, it uses a temporally-based deterministic protocol to coordinate and switch IP packets on a systemwide basis. As a result, end-to-end throughput is guaranteed, without packet loss, loss variance, or accumulated performance impairment; additionally, end-to-end delay is minimized, and jitter is essentially eliminated. We also show that packet sequencing can complement conventional IP networks: sequencing does not negate the use of queue management QoS methods that are the subject of considerable ongoing study. This article describes the fundamental approach, issues associated with scalability, illustrative performance in the context of storage networking, and attributes related to the security and reliability of IP networks.