The IETF Multiprotocol Label Switching Standard: The MPLS Transport Profile Case

Multiprocol Label Switching (MPLS) is a technology for traffic engineering for and the optimization of IP networks. It's also an enabling technology for building applications on top of IP networks. The IETF has standardized the MPLS protocol suite, as well as technologies — such as virtual private networks and pseudowires — that build on it. MPLS is a mature technology and is used extensively by all the major network operators. The IETF has also standardized a technology — Generalized MPLS — that extends the MPLS control plane for use with other data plane technologies.     

物联网国际标准化活动及其标准综述

文章介绍了国际标准组织ITU-T、OneM2M、3GPP、IETF和OMA在物联网标准制定方面的活动,指出了上述标准化组织的不同定位,并总结了ITU-T Y.2060、OneM2M、3GPP TS 23.682、IETF 6LowPan、IETF COAP、OMA DM和OMA LightWeightM2M标准的主要内容/特点。     

IP multicast routing through ATM networks

The purpose of this paper is to have a closer look at the ‘core’ technology providing interworking between connectionless TCP/IP internetworks and switched ATM networks. The scope of the paper is IP multicast, while the main focus is on the network side of multicast, more precisely, on layers three and two of Internet architecture dealing with IP multicast routing. The paper analyses both practically available solutions and those being currently under discussion in IETF as Internet drafts. As a background of this comparison, the possible convergence of IP and ATM multicast service models is discussed. Major conclusions, based on simulation studies and scalability analysis are: (i) the high mapping overhead requires a separate address resolution service for unicast and multicast addresses; and (ii) efficient convergence has to make obsolete classical IP over ATM (M. Laubach, Classical IP and ARP over ATM, Network Working Group, Request for Comments: 1577, Category: Standards Track, January, 1994 [1]) in order to permit ‘cut-through’ within the ATM domain.     

The IETF: laying the Net's asphalt

Since its inception in 1986, the Internet Engineering Task Force (IETF) has helped drive Internet standards. Its guiding principle of “rough consensus and working code” has produced standards like TCP (Transmission Control Protocol), IP (Internet Protocol), and HTTP (Hypertext Transport Protocol). Companies widely adhere to these standards, yet the IETF has no authority to enforce them. Although initially funded by the National Science Foundation, the IETF has no official backing from the US Government; there is no policy requiring software or hardware to follow IETF-developed standards. So why do approximately 1600 people show up at a typical IETF meeting, and why do even large companies, which could well afford the effort to establish their own de facto standards, develop products in accordance with IETF standards? It all boils down to interoperability     

Is the Internet going NUTSS?

For nearly 10 years now, the Internet Architecture Board (IAB) and Internet Engineering Task Force (IETF) have been telling us that the pool of available IP addresses will soon be exhausted, and that Internet growth will come to a grinding halt. They have heavily promoted their solution, IPv6, which the commercial world has all but ignored. It is now becoming clear that IP address exhaustion is years off, at best. The primary reason for this is network address translation (NAT), the rogue technology that allows almost unlimited address reuse. Despite NAT's nagging technical problems that limit IP connectivity and make peer-to-peer (P2P) applications difficult to deploy, the commercial world has universally embraced the technology even as the IAB and IETF actively discourage its use.     

SCTP: new transport protocol for TCP/IP

For the past 20 years (1980-2000), applications and end users of the TCP/IP suite have employed one of two protocols: the transmission control protocol or the user datagram protocol. Yet some applications already require greater functionality than what either TCP or UDP has to offer, and future applications might require even more. To extend transport layer functionality, the Internet Engineering Task Force approved the stream control transmission protocol (SCTP) as a proposed standard in October 2000. SUP was spawned from an effort started in the IETF Signaling Transport (Sigtrans) working group to develop a specialized transport protocol for call control signaling in voice-over-IP (VoIP) networks. Recognizing that other applications could use some of the new protocol's capabilities, the IETF now embraces SCTP as a general-purpose transport layer protocol, joining TCP and UDP above the IP layer. Like TCP, STCP offers a point-to-point, connection-oriented, reliable delivery transport service for applications communicating over an IP network     

Mobile IPv6 and the future of wireless Internet access

Wireless technology is increasingly being used for Internet access and other IP-based communications. To make it easier for wireless users to exploit this trend, the Internet Engineering Task Force (IETF) designed Mobile IP version 4 in 1996. However, MIPv4 has not been deployed widely enough to provide much mobility and has several major shortcomings, including a cumbersome communications process and a limited number of IP addresses. The latter is a key problem because the number of mobile devices that need their own IP address to access the Internet is increasing rapidly. To overcome these deficiencies and introduce new capabilities, the IETF has been developing MIPv6. MIPv6 makes many more IP addresses available and lets mobile users stay connected to the Internet as they move between networks. The paper discusses MIPv6 implementation.     

Performance of intelligent Mobile IPv6

Mobile IP is the current standard proposed by IETF for mobility management in IP networks. Mobile node communicating with static correspondent node (CN) has been considered in previous performance studies. We propose the mobility of CN and two additional mobility combinations for Mobile IP in this paper. CN mobility causes performance degradation in an environment with frequent handoffs. A new scheme for Mobile IPv6 called Intelligent Mobile IPv6 is proposed. It is observed through simulation results that the performance of Intelligent Mobile IPv6 is better than Mobile IPv6.     

Loop-free alternates and not-via addresses: A proper combination for IP fast reroute?

The IETF currently discusses fast reroute mechanisms for IP networks (IP FRR). IP FRR accelerates the recovery in case of network element failures and avoids micro-loops during re-convergence. Several mechanisms are proposed. Loop-free alternates (LFAs) are simple but cannot cover all single link and node failures. Not-via addresses can protect against these failures but are more complex, in particular, they use tunneling techniques to deviate backup traffic. In the IETF it has been proposed to combine both mechanisms to merge their advantages: simplicity and full failure coverage.This work analyzes LFAs and classifies them according to their abilities. We qualitatively compare LFAs and not-via addresses and develop a concept for their combined application to achieve 100% single failure coverage, while using simple LFAs wherever possible. The applicability of existing LFAs depends on the resilience requirements of the network. We study the backup path length and the link utilization for both IP FRR methods and quantify the decapsulation load and the increase of the routing table size caused by not-via addresses. We conclude that the combined usage of both methods has no advantage compared to the application of not-via addresses only.     

AiOLoS: A model for assessing organizational learning in software development organizations

ContextIn an industry in which technological developments are rapid, in order to keep up with the continuously increasing competition and to obtain competitive advantage, the software development organizations (SDOs) need to obtain the correct knowledge, use it efficiently and pass it to future projects evolving it accordingly.ObjectiveThe main aim of this paper is to propose a novel model, AiOLoS, for assessing the level and characteristics of organizational learning (OL) in SDOs.MethodThe primary contributions of this two-legged AiOLoS model are the identification of the major process areas and the core processes that a learning software organization (LSO) follows during its OL process and to provide the necessary measures and the corresponding definitions/interpretations for the assessment of the learning characteristics of the SDO. The research is supported with a multiple case-study work to identify the mapping of the core processes and the applicability of the AiOLoS model to SDOs, its utilization as a tool for assessing OL and providing a basis for software process improvement (SPI).ResultsThe case studies have shown that not only the AiOLoS measures are applicable to SDOs but also that they measure in great extent the actual OL that is realized in the organization and that the major process areas and core processes are actually related to the OL process of SDOs.ConclusionAiOLoS has been designed to provide a starting point for the enhancement of OL capabilities of SDOs, which in turn should provide a basis to conduct SPI activities. Therefore, it is also important to investigate a possible binding of AiOLoS to SPICE and the inclusion of a maturity dimension to AiOLoS.     

Learning to assert yourself [review of Creating Assertion-Based IP (H.D. Foster and A.C. Krolnik; 2008)]

This is a review of Creating Assertion-Based IP (by Harry D. Foster and Adam C. Krolnik)—a tutorial on creating assertion-based verification IP for real designs, applicable to various classes of design blocks found in today's systems. This book uses the specific syntax of System-Verilog Assertions (SVA) and the verification environment of the Advanced Verification Methodology (AVM). However, the same principles apply to other assertion specification languages and within the context of other verification environments. Perhaps most importantly, this book teaches a way of thinking about creating and using assertion-based verification IP.     

Innovation among different classes of software development organizations

Software development organizations (SDOs) innovate in diverse ways. In this paper, based on an extensive review of innovation typologies, we develop a theory‐driven typology of SDO innovator classes. We theorize about the driving forces behind these classes, with specific attention given to knowledge‐based dispositions that relate to the SDO's knowledge‐based competencies in technology appropriation, technology generation, and network intensity within ecological niches. Through a survey of 136 SDOs, which adopted Internet technologies during 1995‐2006, we empirically verify that these classes also determine different ways that SDOs innovate around software services they provide to their clients. Our findings suggest that the knowledge‐based dispositions of different SDO innovator classes impact how they innovate. Overall, the study involves theorizing around different types of innovation behaviours and associated knowledge‐based factors that influence the way SDOs innovate.     

通信网络新技术--多协议标记交换

多协议标记交换(MPLS)由IETF制订标准以来，得到了迅速的发展和应用。在Internt上，该技术已成为下一代网络通信中提高网络性能、容量的关键，文章介绍了MPLS技术的发展过程、特点优势、对IP网络的支持以及其工作的基本原理，并介绍它在我国的发展现状。     

VxWorks操作系统中SCTP协议栈的研究与实现

随着IP网向多业务网的发展,尤其是近年来VoIP技术的发展,需要在IP网络上传输有严格时间要求的信令。IETF的信令传输工作组(SIGTRAN)定义了一种新的传输层协议：SCTP(流控制传输协议),用于在IP网上提供可靠的报文传输。本文实现了BSD的SCTP协议栈源代码到VxWorks上的移植。同时分析了VxWorks中SCTP协议栈的实际运行性能。     

SCTP: What, Why, and How

Similar to TCP and UDP, the stream control transmission protocol (SCTP) is a transport protocol providing end-to-end communication. SCTP was originally designed within the IETF Signaling Transport (SIGTRAN) working group to address TCP's shortcomings relating to telephony signaling over IP networks. SCTP has since evolved into a general-purpose IETF transport protocol with kernel implementations on various platforms. Similar to TCP, SCTP provides a connection-oriented, reliable, full- duplex, congestion and flow-controlled layer 4 channel. Unlike both TCP and UDP, however, SCTP offers new delivery options that better match diverse applications' needs. Here, we introduce SCTP, discuss its innovative services, and outline ongoing SCTP-related research and standardization activities.     

The Communications Assistance for Law Enforcement Act (CALEA)

ABSTRACT

A number of laws have been passed in recent decades governing the wiretapping and interception of conversations on the Public Switching and Telecommunications Network and the Internet. The Communications Assistance for Law Enforcement Act (CALEA) passed in 1994 requires that digitally switched telephone networks be designed and built with wiretap capabilities and that service providers assist law enforcement agencies (LEA) in obtaining the desired surveillance. The Federal Communications Commission (FCC) in 2005 ruled that the CALEA also applies to Voice over IP (VoIP) conversations. This initially generated considerable contention among the Internet community regarding the extent to which wiretapping should be embedded into the applicable Internet protocols.

The International Engineering Task Force (IETF) has provided general guidelines in RFC 3924 regarding architecture for the interception and availability of the information to the LEAs but has declined to produce a full-fledged standard. The guidelines proposed by the IETF were heavily influenced by Internet Service Provider (ISP) component manufactures and define a generic architecture based on the functionality of major components. These components are defined in such a manner as to properly configure network devices for the required intercept, limiting access to the information, and passing the intercepted information to the designated LEA. The IETF guidelines define the functional boundaries and communication between the ISP components and the LEA.     

SIP协议的认证机制及其性能分析

SIP协议是IETF提出的IP电话标准,有着很好的应用前景。讨论了SIP协议的安全认证机制,并通过基于开放源码的Java程序在一个SIP代理服务器上的执行,对该应用中SIP协议安全机制及有关性能进行了分析评价。     

在Linux环境下SIP通信的实现

SIP(Session Initiatioan Protocol)协议是由IETF工作组于1997年7月提出的,是应用层的控制协议,能建立、调整和终止多媒体的呼叫和会话。SIP协议是基于文本方式的,即以明文方式传输。SIP消息包括请求消息、应答消息。SIP协议侧重于将IP电话作为因特网上的一个应用,并且也采用RTP作为媒体传输的协议。本文在SIP通信过程中,采用面向连接的TCP来传输SIP的交互信令,采用面向无连接的UDP协议进行实时音频流传输。本设计是在Linux操作系统下,用套接字(socket)来实现的。设计实现了SIP协议的整个通信过程。最后,提出了进一步开发的设想。     

移动IP技术及其存在的问题与改进

为了满足移动计算机用户对Internet移动接入需求的急剧增长，IETF在IPv4的基础上设计了移动IPv4协议。本文介绍了移动IPv4技术的关键概念、基本特点和工作过程，并提出了当前存在的问题以及一些可能的改进方法。IPv6是IPv4的下一版，它对IPv4作了重大改进，本文后面重点介绍了IPv6对移动IP的支持，并比较了与移动IPv4的不同之处。     

交互式IP多播技术及其在多点视频会议中的应用研究

文章介绍了ITU的H.323多点视频会议标准、IETF的多媒体会议标准、IP多播技术以及RTP/RTCP协议,综合两种视频会议标准的特点提出了交互式IP多播技术,给单向的IP多播增加交互功能,使用简单的方法实现多点视频会议,而不需要昂贵的MCU支持;文章给出了该技术在多点视频会议系统中应用的详细说明和简单的应用实现,使基于IP多播的多点视频会议可以利用RTCP控制包和TCP服务端口有效地解决会议主动成员的可管理性,同时保留了IETF多媒体会议的可扩展性。