应用于ROHC的窗基LSB编解码修正算法实现机制

在移动：IPv6中，常常因为数据分组的头标太大而消耗过多的带宽，因而需要使用灵活可靠的鲁棒性头标压缩机制(ROHC)来对分组头标进行压缩。在ROHC中，使用LSB编码方案对分组中那些变化比较小的头标域进行编码。本文将在简要介绍ROHC原理的基础上，深入探讨应用于ROHC的窗基LSB编解码修正算法的实现机制。     

Modified and Improved IPv6 Header Compression (MIHC) Scheme for 6LoWPAN

Internet of Things with the use of sensors has opened a huge window for applications in almost every area of life and its penetration is endless with wireless connectivity. It is resulting in communication among sensor nodes connected in a low power wireless personal area network (LoWPAN). This requires transmission of IPv6 packets over Low-power wireless personal area network and is called 6LoWPAN. The frame size of 802.15.4 (IEEE standard for wireless network) is only of 127 bytes. The large sized headers like link layer header, security bits, IPv6 header, and UDP header consume most of the packet space leaving only 28 bytes for actual payload. Hence to provide a substantial number of bytes for the payload, header compression becomes a necessity in 6LoWPAN. Header compression also leads to smaller packet size which in turn will consume less bandwidth and power. 6LoWPAN is a resource constraint environment in which such a thing is desirable. Hence IPv6 header compression is 6LoWPAN not only provides more space for data payload but it also consumes less power, bandwidth and results in lesser delays. This paper proposes “Modified and Improved IPv6 Header Compression” (MIHC), a compression technique for IPv6 header in 6LoWPAN environment. The compression mechanism is based on correlation of headers present in the packets which are being transmitted from a source node to destination. We have implemented it in Contiki 3.0 and simulated using Cooja simulator. Results shows that the proposed mechanism MIHC outperforms IPHC and NO_COMP with 20 and 76% higher throughput, 13 and 38% lesser delay, 12 and 37% less round trip time and 13 and 39% reduced packet size respectively. Application of T test on measured values shows a significant difference (p?<?0.5) between No header compression case i.e. NO_COMP and our proposed algorithm i.e. MIHC.     

Low‐loss TCP/IP header compression for wireless networks

Wireless is becoming a popular way to connect mobile computers to the Internet and other networks. The bandwidth of wireless links will probably always be limited due to properties of the physical medium and regulatory limits on the use of frequencies for radio communication. Therefore, it is necessary for network protocols to utilize the available bandwidth efficiently. Headers of IP packets are growing and the bandwidth required for transmitting headers is increasing. With the coming of IPv6 the address size increases from 4 to 16 bytes and the basic IP header increases from 20 to 40 bytes. Moreover, most mobility schemes tunnel packets addressed to mobile hosts by adding an extra IP header or extra routing information, typically increasing the size of TCP/IPv4 headers to 60 bytes and TCP/IPv6 headers to 100 bytes. In this paper, we provide new header compression schemes for UDP/IP and TCP/IP protocols. We show how to reduce the size of UDP/IP headers by an order of magnitude, down to four to five bytes. Our method works over simplex links, lossy links, multi‐access links, and supports multicast communication. We also show how to generalize the most commonly used method for header compression for TCP/IPv4, developed by Jacobson, to IPv6 and multiple IP headers. The resulting scheme unfortunately reduces TCP throughput over lossy links due to unfavorable interaction with TCP's congestion control mechanisms. However, by adding two simple mechanisms the potential gain from header compression can be realized over lossy wireless networks as well as point‐to‐point modem links. This revised version was published online in June 2006 with corrections to the Cover Date.     

一个无线传感器网络中的ipv6协议栈头部压缩方案

提出了一个无线传感器网络中的IPv6协议栈的头部压缩方案,包括IPv6头部、扩展头部和UDP头部的压缩.该方案易于实现,能够较大程度的减少无线传感器网络中报文的传输时间,从而降低能量消耗,延长节点寿命.     

无线网络中提高IP传输效率方法分析

随着无线通信技术的发展,业务种类和数据量急剧增加,使得有限的频带资源变得更加紧张,因此在无线IP网络里,对数据包进行压缩,可以有效提高链路的利用率。这里主要讨论对数据包头进行压缩来提高传输效率。通过分析目前无线网络中IP层传输效率提高的瓶颈,结合目前常用的包头压缩技术,分析了IETF提出的IPHC和ROHC这2种IP头部压缩的方法,并结合无线信道的特点提出适合短生命周期的报文进行头部压缩的机制。     

Evaluation of header compression schemes for IP-based wireless access systems

For mobile IP-based telephony (voice over IP) and IP-based real-time multimedia over cellular radio systems, an economically viable solution is needed. It is an absolute requirement that, for example, the 60-octet IPv6/UPD/RTP headers on IP telephony packets be reduced in size to conserve bandwidth in the radio spectrum. We evaluate the performance of two header compression schemes, based on RFCs 2508 and 3095, under the conditions of cellular radio access technology. The results presented in this article refer to voice and Web browsing traffic and are based on the implementation of compression/decompression algorithms for the aforementioned standards. We find that RFC 3095 performs significantly better if used for mobile communications.     

无线因特网中信头压缩技术研究

综述了信头压缩技术及相关研究成果,介绍了ROHC协议基本原理,分析了基于窗口的最低有效位（W—LSB）编码算法,通过仿真给出了ROHC的一些关键参数的优化值,这些优化值可以兼顾ROHC协议的压缩率和鲁棒性,从而使ROHC性能得到优化。     

头标压缩算法在移动IPv6中的应用

无线网络的带宽相对较窄,为了解决移动IPv6分组头标开销过大问题,本文提出了移动IPv6头标压缩算法。在无线链路上仅在数据流开始的时候发送完整的分组和选项头标,后续的IPv6分组只传送头标域中的变化部分和相对同一个流的关键标识符,在无线链路的两端压缩/解压缩分组头标。该算法有较好的容错功能,有效利用了无线带宽,应用前景广阔。     

卫星IP网络包头压缩技术分析

由于IP数据包头带来的较大开销,在卫星链路上传输IP数据包效率较低。分析了健壮性头标压缩协议(ROHC)在卫星通信系统中应用的可行性,在Linux平台对ROHC进行了实现。描述了ROHC在内核中的实现方法,提出了ROHC在内核中的嵌入方式,介绍了压缩器和解压器的实现流程,对ROHC实现进行了测试和性能分析。实验测试表明,采用ROHC极大减少了IP数据包头长度,大大提高了IP业务卫星带宽利用率。     

GSE: A flexible,yet efficient,encapsulation for IP over DVB‐S2 continuous generic streams

The second‐generation specification for Digital Video Broadcast over Satellite, DVB‐S2, defines an improved and adaptive physical layer. A new framing structure at the link layer, known as the generic stream (GS), is introduced offering an alternative to the well‐known MPEG transport stream (TS). This paper presents the requirements for and the design of an encapsulation protocol to transport IPv4 and IPv6 datagrams and other network protocol packets directly over DVB‐S2 using this GS profile. The resulting generic stream encapsulation (GSE) is a novel method that provides flexible encapsulation with support for fragmentation. A flexible extension header format allows GSE to carry additional header information, suitable for enhanced features, such as link layer encryption and IP header compression. The paper assesses GSE performance by simulation using realistic traffic profiles and attenuation fading. This demonstrates considerable improvement in efficiency compared with the MPE/MPEG‐2 TS, especially when used with adaptive coding and modulation (ACM). Although designed for DVB‐S2 systems, the new encapsulation is suitable for other second‐generation physical layer standards. Copyright © 2008 John Wiley & Sons, Ltd.     

LTE系统中自适应鲁棒性报头压缩算法

LTE系统采用全IP承载,具有比以往无线系统更高的数据速率和更大的系统容量.为了更好地利用系统无线带宽资源,LTE采用了灵活可靠的鲁棒性报头压缩机制(ROHC)来处理过大的无线分组报头.由于无线环境的动态变化,信道质量也会随时发生变化,ROHC压缩算法将变得不大适用.为此,提出了一种自适应的鲁棒性报头压缩算法,根据无线信道的变化情况动态调整ROHC压缩的参数.通过仿真结果表明,相比于ROHC协议的压缩算法,提出的算法具有更好的压缩效率,同时具有更好的适用性.     

一种对3G网络无线链路上ROHC的改进方法

介绍了ROHC这种目前公认应用于无线链路上较为理想的头部压缩方式。通过对其模式转换的分析，发现了其中鲁棒性与压缩效率未能兼顾的缺点，从而讨论了一种新的模式转换的改进方法，进一步提高了ROHC的鲁棒性与压缩效率的平衡性。最后，用仿真实验验证了改进方法的有效性。     

Design and Realization of a Novel Header Compression Scheme for Ad Hoc Networks

IP header compression schemes offer a valuable measure for bandwidth preservation. Such schemes have been practically implemented in infrastructure‐based IP networks for point‐to‐point links. However, minimal research and practical implementation efforts have been conducted in the direction of an IP header compression strategy that can meet the peculiar requirements of multi‐hop ad hoc wireless networks. In this paper, we present a practically implemented multi‐hop IP header compression scheme using the Robust Header Compression (ROHC) protocol suite. The scheme runs on a novel identifier (ID) based networking architecture, known as an ID‐based ad hoc network (IDHOCNET). IDHOCNET additionally solves a number of bottlenecks of pure IP‐based ad hoc networks that have emerged owing to IP address auto‐configuration service, distributed naming and name resolution, and the role of an IP address as an identifier at the application layer. The proposed scheme was tested on a multi‐hop test bed. The results show that the implemented scheme has better gain and requires only O (1) ROHC contexts.     

Internet protocol header compression, robust header compression, and their applicability in the global information grid

IPv6 extends capabilities of legacy IPv4 networks. The advantages of IPv6, however, come at the cost of increased operational overhead. As government networks providing services to the global information grid (GIG) migrate toward an IPv6-based infrastructure, the implications of an expanded packet header must be analyzed. This article describes two IPv6 applicable header compression schemes developed by the IETF, and how networks across the GIG infrastructure can adopt them in an effort to reduce IPv6 expanded overhead requirements.     

G-SRv6头压缩优化技术研究与应用

SRv6作为新一代IP网络核心技术,逐步成为5G和云时代的网络演进方向。如何解决头部开销过大、承载效率低、现网升级难的问题,使SRv6可实际商用部署,已经成为业界关注的焦点。基于这一技术难题,首先提出头压缩设计需求,包括：兼容标准SRv6头部封装,继承标准SRv6和IPv6优势,兼容当前网络地址规划,达成压缩效率与处理性能的有效平衡,与现有网络互联互通;其次,提出基于公共前缀拼接的G-SID头压缩方案,定义G-SID Container、COC Flavor、SI的关键技术能力,并提出压缩和非压缩网络混合部署的网络编排方式;最后,介绍G-SID方案在业界国际标准的进展,通过多厂商设备互通验证可行,并计划现网试点部署,推进SRv6全网快速落地。     

WiMAX自适应健壮性报头压缩算法

由于WiMAX通信传输协议框架中各层协议的报头含有太多的冗余信息,导致了无线信道带宽的利用率较低。同时由于分组过长也会引起误码率的增加。为了解决WiMAX中报头开销过大问题,提高无线信道带宽利用率,结合ROHC压缩算法和WiMAX MAC协议,提出了WiMAX自适应健壮性报头压缩方案。通过分析W-LSB编码,给出了自适应健壮性报头压缩算法在WiMAX的实现过程。仿真结果表明：该算法可以将60个字节的RTP/UDP/IPv6报头压缩到1～3个字节;可以适应WiMAX通信系统链路特性经常变化的无线信道,能够在报头压缩率和抗差错鲁棒性之间获得较好的平衡性。     

A hierarchical scheme on achieving all-IP communication between WSN and IPv6 networks

The paper proposes a hierarchical scheme on implementing all-IP communication between wireless sensor networks and IPv6 networks. The paper proposes the cluster-tree architecture for all-IP wireless sensor networks which is consistent with the IPv6 Internet architecture. Based on the cluster-tree architecture, the paper proposes the hierarchical IPv6 address configuration algorithm where the IPv6 configuration for cluster members in different clusters can be performed simultaneously, so the IPv6 configuration delay is shortened. Based on the proposed cluster-tree architecture and the IPv6 address configuration algorithm, the paper proposes the hierarchical routing scheme in the link layer where the intermediate nodes only need to deal with the frame header in the link layer without processing the headers in the above layers, so the routing delay is shortened and the power consumption is reduced. From both theoretical perspective and simulative perspectives, the paper analyze the performance parameters of the proposed scheme. And the data results show that the performance of the proposed scheme is better.     

Voice quality evaluation in wireless packet communication systems: a tutorial and performance results for RHC

As wireless systems evolve toward supporting a wide array of services, including traditional voice service, using packet-switched transport, it becomes increasingly important to assess the impact of packet-switched transport protocols on voice quality, in this article we present a tutorial on voice quality evaluation for wireless packet-switched systems. We introduce an evaluation methodology that combines elementary objective voice quality metrics with a frame synchronization mechanism. The methodology allows networking researchers to conduct effective and accurate quality evaluation of packet voice. To illustrate the use of the described evaluation methodology and interpretation of the results, we conduct a case study of the impact of robust header compression (ROHC) on the voice quality achieved with real-time transmission of GSM encoded voice over a wireless link.     

机载移动通信卫星中继链路的高效传输方法

为了提高机载移动通信卫星中继链路的数据传输效率,给出了一种高效传输方法,先通过转换话音编码方式对语音进行压缩,再把话音数据作为有效负载封装成IP数据包,采用RTP复用和IP/UDP/RTP报头压缩等技术来提高话音数据的传输效率.最后通过仿真说明了这种高效传输方法能提升给机载移动通信的性能.     

Mobile IPv6 network: implementation and application

Recently, the world has become increasingly mobile, and people have started communicating by wireless networking. Mobile IPv6 enables mobile users to communicate with each other while moving. In this study, a mobile IPv6 network was implemented by the IEEE 802.11 specification, and its performance was analyzed using TCP and UDP applications. The experimental results indicate that throughput stabilized for UDP applications after about 6–14 seconds. However, TCP applications were found to stabilize throughput in 10–20 seconds. The evaluation results reveal that TCP applications perform less well in mobile IPv6 networking than UDP applications. Copyright © 2006 John Wiley & Sons, Ltd.