Design and implementation of a high-speed transport protocol

The design, analysis, and implementation of an end-to-end transport protocol that is capable of high throughput consistent with the evolving high-speed physical networks based on fiber-optic transmission lines and high-capacity switches are presented. Unlike current transport protocols in which changes in control/state information are exchanged between the two communicating entities only when some significant event occurs, this protocol exchanges relevant and full state information periodically and frequently. It is shown that this reduces the complexity of protocol processing by removing many of the procedures required to recover from network inadequacies such as bit errors, packet loss, and out-of-sequence packets and makes it more amenable to parallel processing. Also, to increase channel utilization in the presence of high-speed, long-latency networks and to support diagrams, and efficient implementation of the selective repeat method of error control is incorporated in the protocol. An implementation using a Motorola 68030-based multiprocessor as a front-end processor is described. The current implementation can comfortably handle 10-15 kpackets/s     

A Protocol for Packet Network Intercommunication

A protocol that supports the sharing of resources that exist in different packet switching networks is presented. The protocol provides for variation in individual network packet sizes, transmission failures, sequencing, flow control, end-to-end error checking, and the creation and destruction of logical process-to-process connections. Some implementation issues are considered, and problems such as internetwork routing, accounting, and timeouts are exposed.     

An in-band power-saving protocol for mobile data networks

A new alternative is proposed for reducing the power consumption of the portable (battery-powered) units operating in a mobile packet-data network. First, a review of the current power-saving protocols is given. It is shown that the most common means for conserving power is the intermittent operation of the receivers (at the portable units) and a central administration authority that synchronizes the receivers. Some drawbacks of the synchronous operation lead us to the introduction of an asynchronous power-saving protocol, where no central synchronization is necessary and where each terminal may control its power consumption relative to its current needs. According to the proposed power-saving page-and-answer protocol, an acknowledgment paging procedure is preceding every packet transmission in order to alert mobile terminals with pending traffic. Steady-state performance is evaluated with the aid of simulation. The relationship between the achieved power-saving and the mean packet delay degradation is presented. Finally, we express some notable implementation issues and some considerations regarding the employment of this protocol as a supplementary power-saving service in microcellular mobile data networks and wireless local area networks     

Advances in photonic packet switching: an overview

The current fast-growing Internet traffic is demanding more and more network capacity every day. The concept of wavelength-division multiplexing has provided us an opportunity to multiply network capacity. Current optical switching technologies allow us to rapidly deliver the enormous bandwidth of WDM networks. Photonic packet switching offers high-speed, data rate/format transparency, and configurability, which are some of the important characteristics needed in future networks supporting different forms of data. In this article we present some of the critical issues involved in designing and implementing all-optical packet-switched networks     

Economic analysis of robust access network architecture in two-tierdata networks

Recent studies have addressed routing and performance issues of nonhierarchical and hierarchical backbone packet networks in a unified fashion, by adopting an end-to-end mean delay objective and including a variety of practical routing constraints. The authors build on this approach to include the design of robust access networks, and they analyze the economic and robustness-related tradeoffs of several access network architectures in two-tier data packet networks. Two-tier architectures consist of an access network that homes to a high-capacity backbone network through a variety of topological arrangements. The access tier provides protocol handling and traffic concentration. The backbone tier performs high-speed transport and alternate routing under congestion/failure conditions. They identify the fundamental access network parameters that allow them to develop network designs with optimized characteristics. The analysis demonstrates the cost effectiveness of access diversity as well as the enhanced robustness it can provide even though it requires higher switch functionality and cost     

Connection establishment in high-speed networks

Protocols for establishing, maintaining, and terminating connections in packet-switched networks have been studied, and numerous standards have been developed to address this problem. The authors reexamine connection establishment in the context of a high-speed packet network, introduce a protocol for connection establishment/takedown that is appropriate for such a network, and explain its advantages over previously proposed protocols. The main features of the proposed protocol are: fast bandwidth reservation in order to avoid as much as possible reservation conflicts, guaranteed release of the reserved bandwidth even under modal and link failures, and soft recovery from processor failures, which allows the maintenance of existing connections under processor failure provided the switch and links do not fail. The underlying model that is used is the PARIS/plaNET network, but the protocol can be adapted to other fast packet networking architectures as well     

High-Speed Packet Switching Systems for Multimedia Communications

High-speed packet switching (HPS) systems can Provide flexible, economical, high-quaiity services for integrated voice, video, and data communications. To realize such HPS systems, methods have been developed to bring about high-speed protocol processing as well as a system architecture for facilitating high-throughput switching. Adopting the parallel processing algorithm into protocol processing allows us to achieve high-speed packet protocol processing of about 100 times faster than conventional processing. Furthermore, a fully distributed system architecture in addition to hierarchical interconnection networks can achieve high-capacity packet switching systems. The proposed HPS system is thus capable of accommodating lines of up to 10-50 Mbits/s, of providing high-throughput switching capability of 1 000 000 packets/s, and of having an average delay of less than 2 ms. Furthermore, an evaluation of network delay performances of video conferencing and voice communications indicate that HPS systems are quite suitable for handling such multimedia communications.     

ATM-based transport architecture for multiservices wirelesspersonal communication networks

This paper presents an ATM-based transport architecture for next-generation multiservices personal communication networks (PCN). Such “multimedia capable” integrated services wireless networks are motivated by an anticipated demand for wireless extensions to future broadband networks. An ATM compatible wireless network concept capable of supporting a mix of broadband ISDN services including constant bit-rate (CBR), variable bit-rate (VBR), and packet data transport is explored from an architectural viewpoint. The proposed system uses a hierarchical ATM switching network for interconnection of PCN microcells, each of which is serviced by high-speed, shared-access radio links based on ATM-compatible cell, relay principles. Design issues related to the physical (modulation), media access control (MAC), and data-link layers of the ATM-based radio link are discussed, and preliminary technical approaches are identified in each case. An example multiservice dynamic reservation (MDR) TDMA media access protocol is then considered in further detail, and simulation results are presented for an example voice/data scenario with a proportion of time-critical (i.e., multimedia) packet data. Time-of-expiry (TOE) based queue service disciplines are also investigated as a mechanism for improving the quality-of-service (QoS) in this scenario     

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.     

The Optimization of Combination Scheme in Cooperative Spectrum Sensing Based on the Practical Reporting Frame Format

Wireless mesh networks (WMNs) are emerged as prominent solution to provide seamless connection to the internet. WMNs are typically used for providing broadband wireless internet access to a large number of users and networks. Guaranteeing the quality of service to end users with efficient resource utilization is a challenging issue in WMNs. To accomplish this, we propose a hybrid routing protocol for wireless mesh networks. It is a combination of intra cluster routing protocol (ICR) and inter cluster routing protocol for mesh networks (ICMR). Intra cluster routing protocol is intended to facilitate the communication between mesh clients within a same cluster and inter cluster routing protocol (ICMR) intended to facilitate the communication for mesh clients from different clusters. Intra cluster routing protocol is a proactive type of routing protocol and inter cluster routing protocol is a reactive type of routing protocol. The performance of the proposed protocol is analyzed and the results shown superior performance compared to baseline routing protocols in terms of throughput, end to end delay, packet delivery ratio and jitter.     

A New Digital Sense Multiple Access (DSMA) Protocol for High-Speed Wireless Networks

In this paper, we propose a new digital sensemultiple access with delayed transmission (DSMA/DT)protocol for reverse channel in high-speed wirelessnetworks. The new protocol is motivated by theobservation that the existing DSMA protocol does not yieldsatisfactory throughput for long round-trip propagationand processing delay, which occurs in outdoor high-speedenvironments or when the receiver hardware requires long signal processing time. The newDSMA/DT protocol is intended to reduce the performanceimpacts of the round-trip delay. Look-ahead busy/idleflag, seizure queueing, and reserved time slots are also devised for the new protocol. Whilerequiring at most two additional status bits on theforward channel and no additional hardware capability,these features further enhance the protocol performance and enable constant-bit-rate service withlittle added complexity in control. The channelthroughput of the DSMA/DT protocol and the optionalfeatures are analyzed. Closed-form expressions for thethroughput are obtained. For non-negligible round-tripdelay relative to packet transmission time, ournumerical results show that the new protocol improvesthe throughput by as much as 60% when compared to theexisting DSMA protocol. For superior performance andsimplicity, the DSMA/DT protocol will be appropriate foruse in high-speed wireless networks.     

Demonstration of 100 Gbps optical packet switching using header processor based on 48-bit longest prefix matching

Wire-rate packet processing and its energy saving for over 100 Gbps speed of line are major issues to be resolved in optical packet switching (OPS) networks. For that purpose, we newly develop a high-speed, deterministic-latency electronic header processor based on longest prefix matching (LPM) for searching optical packet destination addresses (OP-DAs). This paper reports the successful experimental results of electronic header processing based on LPM search of up to 48 bits and optical switching of 100 Gbps optical packets by the use of the header processor. We demonstrate 48-bit LPM-capable optical packet switching. We also demonstrate IP packet transfer and 32-bit LPM-capable optical packet switching. In the latter demonstration, the 32-bit OP-DA of optical packets is directly copied from the 32-bit destination address of Internet Protocol version 4 (IPv4) packets. This result indicates that OPS networks can be deployed with electronic IP networks by the use of integrated network operation between OPS and IP networks.     

Design and Implementation of a Fast Switch Fabric

1　Introduction　ThereferencesystemlogicaldesignweconsiderinFig .1iscommonlyusedinhigh speedrouterimple mentation,suchasIBMQ64G[1～3] .Mostcarrier classpacket switchestodaysupport 8to 1 6linecards[4] ,andeachlinecardmaybefurthersubdivid edintomultiplesub ports.Forexample,anOC 48linecardmaybedividedintofourOC 1 2c ,sixteenOC 3externalinterfaces,etc .Sowepropose 1 6linecardsinourswitchfabricdesign .Mostcurrentre searchfocusesonhigh levelarchitecturalissuesonswitches,butseldomconsidersallth…     

用户空间协议栈的移植与性能优化

文章将一个为嵌入式系统开发的轻量级用户空间协议栈LWIP移植到x86多核处理器上,并通过集成高速收发包引擎、优化关键数据结构及算法等措施提高其性能。论文介绍了与LWIP移植相关的系统模型设计、收发包引擎集成和操作系统抽象层实现,以及与LWIP优化相关的PCB管理、定时器管理与资源互斥锁实现。经实验,基于用户空间协议栈实现的web服务器,其性能比基于内核协议栈的web服务器提高了一倍。     

Network interconnection and gateways

Major technical issues for interconnecting computer networks that must be solved, which include selection of a protocol level at which to interconnect, addressing, routing, fragmentation, and congestion control, are discussed. Specialized gateway devices used to interconnect networks and implement any necessary internet protocols are examined. Two leading alternatives have been developed by the DARPA (Defense Advanced Research Projects Agency) Internet community (datagram internet protocol) and by the CCITT (International Telegraphy and Telephony Consultative Committee) for public data networks (concatenation of virtual circuits). The new ISO standards encompass both approaches, but providing interoperability between them is still a problem     

Transparent generic framing procedure (GFP): a protocol forefficient transport of block-coded data through SONET/SDH networks

The generic framing procedure (GFP) is a new standard that has been developed to overcome data transport inefficiencies or deficiencies with the existing ATM and packet over SONET/SDH protocols. Transparent GFP (GFP-T) is an extension to GFP developed to provide efficient low-latency support for high-speed WAN applications including storage area networks. Rather than handling data on a frame-by-frame (packet-by-packet) basis, GFP-T handles block-coded (e.g., 8B/10B) character streams. This article describes the GFP protocol along with technical considerations and applications for transparent GFP     

A novel signaling nested reservation protocol for all-optical networks

This work proposes a new reservation protocol for enhancing the performance of wavelength-routed networks. To be more robust and reliable, the proposed approach employs distributed control mechanisms. The new method particularly focuses on wavelength-division multiplexed (WDM) core networks with distant end-nodes. It takes into account the considerable amount of data that can be transferred by high-speed WDM networks within limited reservation periods. To increase the throughput, the protocol consumes the unoccupied bandwidth of reservation phases by transferring nonreal-time data packets during these intervals. This scheme is implemented by applying a modified form of backward reservation protocol. To initiate a multihop reservation call, this protocol labels a path as reserved instead of locking it. Meanwhile, labeled nodes with single-hop requests will receive permission signals to send predetermined packet sizes. The length of packets transmitted is defined by the round-trip propagation delay between the current and the upcoming nodes along the path. In case a reservation fails, already labeled nodes will be notified by receiving a prevention signal, which will block them from transferring data packets.     

Performance evaluation of CSMA/ID MAC protocol for IP over WDM ring networks

In this paper, a packet pre‐classification media access control protocol based on a carrier sense multiple access with idle detection (CSMA/ID) scheme is investigated for supporting IP packets over all‐optical WDM ring networks. The purpose of the protocol is to increase throughput and to decrease the packet transmission delay of IP packets over optical networks in a metropolitan area network. This protocol avoids both packet collision and packet fragmentation. In order to improve the utilization of the network, the packets transmitted from a local area network are first pre‐classified into various class queues of an access point (AP) according to their length. After checking the available space based on the wavelength received by the receivers of the AP, the packets in the queues are transmitted. An analytical model is developed to evaluate the performance of the protocol, with simulation results showing good network efficiency. The proposed network has short‐term variations that introduce unfairness conditions. This problem could be overcome by assigning a quota on individual queues to allow all queues fair access. Copyright © 2008 John Wiley & Sons, Ltd.     

Improving mobile network performance with two queueing buffer allocations of priority-based queueing scheme

As current mobile core network systems are expected to evolve into all-IP networks, packet switching will be a prerequisite for all mobile applications. Next-generation mobile networks, as envisioned by ITU-T, are packet-based networks capable of providing consistent and ubiquitous service to end users, independent of the network, access technology, and device used. This study discusses the differentiated packet forwarding performance of four major types of mobile network traffic under the proposed mobile network priority-based queueing (MPQ) scheme with two queueing buffer allocations, namely dynamic queueing buffer (DQB) allocation and overflow queueing buffer (OQB) allocation. As different queueing buffer allocations are adopted to store arriving packets in DQB and OQB, the MPQ scheme shows different packet forwarding performance under these two methods. In this study, we use ns2 (Network Simulator version 2) as the simulation platform to simulate several scenarios. The simulation results show that the MPQ scheme is able to support differentiated packet forwarding behavior for mobile traffic with both DQB and OQB allocations in a mobile core network. Some issues were identified in the MPQ scheme with both DQB and OQB allocation, which will need to be addressed.