Network management of TCP/IP networks: present and future

Recent network management activities in the TCP/IP community have focused on standardizing two network management protocols-Simple Network Management Protocol (SNMP) and Common Management Information Services and Protocol Over TCP/IP (CMOT)-that provide for the exchange of management information. The current SNMP and CMOT approaches to TCP/IP network management are compared from several different perspectives; comparisons are based on both theory and knowledge gained from actual implementation experiences. The current level of user and vendor acceptance for these two protocols is examined and explained, and ongoing standardization efforts are summarized. Relevant ongoing work is summarized, and trends over the next few years are discussed     

一种基于卫星IP网络的数据链路层协议

通过分析卫星通信网络发展趋势,阐述卫星网络中现有的数据链路层协议,梳理归纳卫星网络的特点及影响,提出了一种新型卫星网络数据链路层协议(New Satellite Link Protocol,NSLP)。分析对比表明,该协议能够有效降低链路层报头开销,提高信息传输效率。在实际应用中,新型协议具有能够简化数据链路层的功能,有与TCP/IP协议兼容性好、与IP协议耦合度高、节约星上资源等诸多优点,有利于卫星IP网络整体性能的有效提升。     

SIP: Simple Internet Protocol

Several features of the Simple Internet Protocol (SIP) are described and compared to those offered by the Internet Protocol (IP). The changes required for other protocols in the TCP/IP suite to accommodate SIP are discussed, as are the mechanisms available to allow gradual transition of the Internet from IP to SIP. Future directions for SIP development, a report on current implementation status, and a summary of the specific improvements offered by SIP over IP are presented     

Deploying Internet Protocol Security in satellite networks using Transmission Control Protocol Performance Enhancing Proxies

Applications that use the reliable Transmission Control Protocol (TCP) have a significant degradation over satellite links. This degradation is mainly a consequence of the congestion control algorithm used by standard TCP, which is not suitable for overcoming the impairments of satellite networks. To alleviate this problem, two TCP Performance Enhancing Proxies (PEPs) can be deployed at the edges of the satellite segment. Then these PEPs can use different mechanisms such as snooping, spoofing and splitting to achieve a better TCP performance. In general, these mechanisms require the manipulation of the Internet Protocol (IP) and TCP headers that generates a problem when deploying the standard IP security (IPsec) protocol. The security services that IPsec offers (encryption and/or authentication) are based on the cryptographic protection of IP datagrams, including the corresponding IP and TCP headers. As a consequence, these cryptographic protections of IPsec conflict with the mechanisms that PEPs use to enhance the TCP performance in the satellite link. In this article, we detail the reasons that cause this conflict, and we propose three different approaches to deploy IPsec in a scenario with TCP PEPs. Our proposals provide different trade‐offs between security and TCP performance in some typical scenarios that use satellite networks. Copyright © 2012 John Wiley & Sons, Ltd.     

Optimal design of hybrid FEC/ARQ schemes for TCP over wireless links with Rayleigh fading

In this paper, we investigate interactions between TCP and wireless hybrid FEC/ARQ schemes. The aim is to understand what is the best configuration of the wireless link protocol in order to guarantee TCP performance and channel efficiency. Interactions between TCP and different link layer mechanisms are evaluated by means of an analytic model that reproduces: 1) a Rayleigh fading channel with FEC coding, 2) a generic selective repeat ARQ Protocol, and 3) the TCP behavior in a wired-cum-wireless network scenario. The analytic model is validated-by means of ns-based simulations. The analysis represents a contribution to the optimal design of link layer parameters of wireless networks crossed by TCP/IP traffic. The main findings can be summarized as follows: 1) fully reliable ARQ protocols are the best choice for both TCP performance and wireless link efficiency and 2) optimal values of FEC redundancy degree from the point of view of energy efficiency maximizes TCP performance as well.     

User‐centric context data collection and provision harnessing Content‐Centric Networking paradigm

A comprehensive context management approach is necessary in the era of ubiquitous technologies, and efficient context data collection is one of the most fundamental and important processes for realizing comprehensive context management. Traditional context data collection approaches are based on Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) over Internet Protocol (IP), which has several disadvantages, such as lack of efficient mobility support, security and data transfer efficiency. Content‐Centric Networking (CCN), on the other hand, provides advantages in terms of mobility, security and bandwidth efficiency in comparison with IP. In this paper, we introduce our user‐centric comprehensive context management framework, and propose a secure and efficient context data collection and provision approach based on the framework using CCN as a network and transport layer. This context collection approach provides a flexible security mechanism by introducing three levels of security type. It also provides bandwidth efficiency by taking advantage of CCN's content caching; performance evaluation results show that our approach can reduce bandwidth consumption up to 99% for pull and up to 46% for push in comparison to a UDP/IP‐based system. Our approach also provides advantages in supporting mobility and leveraging multiple interfaces. Copyright © 2013 John Wiley & Sons, Ltd.     

Demultiplexed architectures: a solution for efficient STREAMS-basedcommunication stacks

This article analyzes the efficiency of various high-performance implementation techniques for the communication system of UNIX workstations. Using an open system implies that a certain compatibility level is required from the protocol, user interface, and implementation framework. These constraints limit the opportunities to design a high-performance communication system. The authors have designed an experimental platform around the TCP/IP protocol suite, using the STREAMS environment. A BSD TCP/IP stack and a classic STREAMS-based TCP/IP stack serve as reference implementations for performance comparisons. The article explains why the efficiency of some high-performance implementation techniques the authors have applied to this platform is limited. The impacts of the hardware architecture, operating system, and communication stack architecture on performances are analyzed. It is shown that the efficiency of data transmission would benefit from more simplicity and more synchronism in the communication environment, direct data paths between the applications and the device drivers, and a limited ILP integration     

Bridges and routers

An examination is made of data link bridges and internetwork routers, two technologies that provide for the extension and interconnection of local networks, which may occur using high-speed wide-area digital data communications services. The discussion of bridges covers simple bridges, learning bridges, source routing, and quality of service offered by bridges. The discussion of routers considers the Transmission Control Protocol and Internet Protocol (known as TCP/IP) used by ARPAnet, DECnet, and quality of service offered by routers     

Cross-layer speculative architecture for end systems and gateways in computer networks with lossy links

The throughput degradation of Transport Control Protocol (TCP)/Internet Protocol (IP) networks over lossy links due to the coexistence of congestion losses and link corruption losses is very similar to the degradation of processor performance (i.e., cycle per instruction) due to control hazards in computer design. First, two types of loss events in networks with lossy links are analogous to two possibilities of a branching result in computers (taken vs. not taken). Secondly, both problems result in performance degradations in their applications, i.e., penalties (in clock cycles) in a processor, and throughput degradation (in bits per second) in a TCP/IP network. This has motivated us to apply speculative techniques (i.e., speculating on the outcome of branch predictions), used to overcome control dependencies in a processor, for throughput improvements when lossy links are involved in TCP/IP connections. The objective of this paper is to propose a cross-layer network architecture to improve the network throughput over lossy links. The system consists of protocol-level speculation based algorithms at transport layer, and protocol enhancements at middleware and network layers that provide control and performance parameters to transport layer functions. Simulation results show that, compared with prior research, our proposed system is effective in improving network throughput over lossy links, capable of handling incorrect speculations, fair for other competing flows, backward compatible with legacy networks, and relatively easy to implement.     

Optimizing Router Performance in TCP/IP Networks

This article reviews the steps necessary to configure and implement a complex router internetwork. This article will specifically concentrate on Cisco routers, and since they support Transmission Control Protocol/Internet Protocol (TCP/IP) natively, it will concentrate on a backbone network employing that protocol.     

Dynamically selecting protocols for socket applications

An application enablement method that enables communications applications to run on protocols for which they were not written is discussed. The focus is on a subset of networks and communications application programming interfaces. The communications interface chosen is Berkeley sockets. The network protocols used are SNA (Systems Network Architecture) and TCP/IP (Transmission Control Protocol/Internet Protocol). The running of existing socket applications over SNA networks, which requires support for transparently masking the differences between TCP/IP and SNA from the applications, is described. Protocol selection, address mapping, and connection management are also described     

Performance Evaluation of SCTP Protocol in Linux

SCTP (Stream Control Transmission Protocol) is a protocol of the TCP/IP stack, initially conceived for transport of telephony signaling messages. This article shows a series of performance tests executed on the Linux Kernel SCTP implementation (LK-SCTP).     

一种用于TCP/IP减荷的体系结构

TCP/IP减荷的目的是为了将系统主处理器从用于协议处理的繁重的内核中断服务中解脱出来。笔者从对TCP/IP减荷的需求出发,分析了TCP/IP减荷在设计方面的要求,进而提出了一种用于TCP/IP减荷的体系结构。     

一种小型嵌入式TCP/IP协议栈的设计与实现

设计并实现了一个运行在低端8/16位MCU上的小型嵌入式TCP/IP协议栈。在设计和实现过程中,允许应用程序参与数据的重发,以减少协议栈对资源的消耗。实现了一个最小可达7K,并具有较高响应速度的小型TCP/IP协议栈。     

An empirical study of TCP/IP performance over FR/ATM service interworking

This article outlines some basic performance characteristics of the Transmission Control Protocol/Internet Protocol (TCP/IP) over Frame Relay/Asynchronous Transfer Mode (FR/ATM) Service Interworking. The conclusions are based on empirical TCP/IP performance test results collected on a FR/ATM Service Interworking testbed, architected with commercially available IP, FR, and ATM equipment. © 1998 John Wiley & Sons, Ltd.     

A high-performance network architecture for a PA-RISC workstation

With current low-cost high-performance workstations, application-to-application throughput is limited more by host memory bandwidth than by the cost of protocol processing. Conventional network architectures are inefficient in their use of this memory bandwidth, because data is copied several times between the application and the network. As network speeds increase further, network architectures must be developed that reduce the demands on host memory bandwidth. The authors discuss the design of a single-copy network architecture, where data is copied directly between the application buffer and the network interface. Protocol processing is performed by the host, and transport layer buffering is provided on the network interface. They describe a prototype implementation for the HP Apollo Series 700 workstation family that consists of an FDDI network interface and a modified 4.3BSD TCP/IP protocol stack, and report some early results that demonstrate twice the throughput of a conventional network architecture and significantly lower latency     

Efficient Integration of IP-Based Terrestrial and Satellite Systems: ARQ Techniques and Inter-Segment Handover

A satellite communication system is an excellent candidate toprovide broadband integrated Internet services to globallyscattered users. The inter-operation between a satellite systemand the existing terrestrial Internet infrastructure introducesnew challenges at different layers. Automatic Repeat reQuest (ARQ)techniques have been introduced at radio link layer to improve theperformance of Transport Control Protocol (TCP)/IP over wirelessterrestrial links, but these techniques are usually dismissed inpresence of high latency links such as satellite links. In thispaper, we will show that a truncated power control can effectivelyimprove the trade-off delay-residual error after retransmissionsand makes ARQ techniques a feasible solution for error control insatellite links. Furthermore, mobility management issues inpresence of satellite diversity are addressed. Performance of anInter-Segment Hand-Over (ISHO) procedure, in terms of propagationdelay, will be carried out through simulation for different spacesegment configurations.     

Network security via reverse engineering of TCP code: vulnerabilityanalysis and proposed solutions

The Transmission Control Protocol/Internet Protocol (TCP/IP) suite is widely employed to interconnect computing facilities in today's network environments. However, there exist several security vulnerabilities in the TCP specification and additional weaknesses in a number of its implementations. These vulnerabilities may allow an intruder to “attack” TCP-based systems, enabling him/her to “hijack” a TCP connection or cause denial of service to legitimate users. The authors analyze the TCP code via a “reverse engineering” technique called “program slicing” to identify several of these vulnerabilities, especially those that are related to the TCP state-transition diagram. They discuss many of the flaws present in the TCP implementation of many widely used operating systems, such as SUNOS 4.1.3, SVR4, and ULTRIX 4.3. The corresponding TCP attack “signatures” (including the well-known 1994 Christmas Day Mitnick Attack) are described, and recommendations are provided to improve the security state of a TCP-based system (e.g., incorporation of a “timer escape route” from every TCP state). Also, it is anticipated that wide dissemination of this article's results may not only lead to vendor patches to TCP code to plug security holes, but also raise awareness of how program slicing may be used to analyze other networking software and how future designs of TCP and other software can be improved     

TUBA: replacing IP with CLNP

The Connectionless Network Protocol (CLNP), which is supported by the associated OSI routing protocols, is proposed as a replacement for the Internet Protocol (IP). The basis of the proposal is to run the Internet transport protocols, the Transmission Control Protocol (TCP), and the User Datagram Protocol (UDP) on top of CLNP in an approach known as TCP and UDP with bigger addresses (TUBA). The fundamentals of CLNP and the OSI connectionless routing architecture, the operation of the IP suite with CLNP replacing IP, the support of Internet applications operating on top of TUBA, and a transition plan to a TUBA Internet are discussed     

Nonintrusive TCP connection admission control for bandwidthmanagement of an Internet access link

We describe our approach to monitoring and managing the bandwidth of an Internet edge link with a view toward certain quality of service objectives for the services it carries. Such a link could be, for example, a campus's Internet access link or a small ISP's backbone access link. We use SNMP polls and packet snooping to obtain traffic statistics, and TCP admission control for bandwidth management. Our implementation is completely nonintrusive: we use Ethernet packet capture in the promiscuous mode for traffic analysis, and IP masquerading for blocking new TCP connections. This approach has been implemented by us in a software system for traffic management. We first justify our approach with a simple analytical model. We give an overview of our software implementation, and discuss some implementation issues. Then we provide measurement results that show the effectiveness of the techniques