Web cache replacement policies: a pragmatic approach

Research involving Web cache replacement policy has been active for at least a decade. In this-article we would like to claim that there is a sufficient number of good policies, and further proposals would only produce minute improvements. We argue that the focus should be fitness for purpose rather than proposing any new policies. Up to now, almost all policies were purported to perform better than others, creating confusion as to which policy should be used. Actually, a policy only performs well in certain environments. Therefore, the goal of this article is to identify the appropriate policies for proxies with different characteristics, such as proxies with a small cache, limited bandwidth, and limited processing power, as well as suggest policies for different types of proxies, such as ISP-level and root-level proxies.     

Chord: a scalable peer-to-peer lookup protocol for Internet applications

A fundamental problem that confronts peer-to-peer applications is the efficient location of the node that stores a desired data item. This paper presents Chord, a distributed lookup protocol that addresses this problem. Chord provides support for just one operation: given a key, it maps the key onto a node. Data location can be easily implemented on top of Chord by associating a key with each data item, and storing the key/data pair at the node to which the key maps. Chord adapts efficiently as nodes join and leave the system, and can answer queries even if the system is continuously changing. Results from theoretical analysis and simulations show that Chord is scalable: Communication cost and the state maintained by each node scale logarithmically with the number of Chord nodes.     

SCORE: a scalable communication protocol for large-scale virtual environments

This paper describes and analyzes SCORE, a scalable multicast-based communication protocol for large-scale virtual environments (LSVE) on the Internet. Today, many of these applications have to handle an increasing number of participants and deal with the difficult problem of scalability. We propose an approach at the transport layer, using multiple multicast groups and multiple agents. This approach involves the dynamic partitioning of the virtual environment into spatial areas and the association of these areas with multicast groups. It uses a method based on the theory of planar point processes to determine an appropriate cell size, so that the incoming traffic at the receiver side remains with a given probability below a sufficiently low threshold. We evaluate the performance of our scheme and show that it allows to significantly improve the participants' satisfaction while adding very low overhead.     

Cryptanalysis of scalable multicast security protocol

We show that the scalable multicast security protocol based on RSA, proposed by R. Molva and A. Pannetrat (see ACM Trans. Inform. Syst. Security, vol.3, no.3, p.136-60, 2000), is insecure against collusion attacks.     

CaPPS: cache partitioning with partial sharing for multi-core embedded systems

As the number of cores in chip multi-processor systems increases, the contention over shared last-level cache (LLC) resources increases, thus making LLC optimization critical, especially for embedded systems with strict area/energy/power constraints. We propose cache partitioning with partial sharing (CaPPS), which reduces LLC contention using cache partitioning and improves utilization with sharing configuration. Sharing configuration enables the partitions to be privately allocated to a single core, partially shared with a subset of cores, or fully shared with all cores based on the co-executing applications’ requirements. CaPPS imposes low hardware overhead and affords an extensive design space to increase optimization potential. To facilitate fast design space exploration, we develop an analytical model to quickly estimate the miss rates of all CaPPS configurations using the applications’ isolated LLC access traces to predict runtime LLC contention. Experimental results demonstrate that the analytical model estimates cache miss rates with an average error of only 0.73 % and with an average speedup of \(3505\times \) as compared to a cycle-accurate simulator. Due to CaPPS’s extensive design space, CaPPS can reduce the average LLC miss rate by as much as 25 % as compared to baseline configurations and as much as 14–17 % as compared to prior works.     

A protocol for scalable loop-free multicast routing

In network multimedia applications such as multiparty teleconferencing, users often need to send the same information to several (but not necessarily all) other users. To manage such one-to-many or many-to-many communication efficiently in wide-area internetworks, it is imperative to support and perform multicast routing. Multicast routing sends a single copy of a message from a source to multiple receivers over a communication link that is shared by the paths to the receivers. Loop-freedom is an especially important consideration in multicasting because applications using multicasting tend to be multimedia and bandwidth intensive, and loops in multicast routing duplicate looping packets. We present and verify a new multicast routing protocol, called multicast Internet protocol (MIP), which offers a simple and flexible approach to constructing both group-shared and shortest-paths multicast trees. MIP can be sender-initiated or receiver-initiated or both; therefore, it can be tailored to the particular nature of an application's group dynamics and size. MIP is independent of the underlying unicast routing algorithms used. MIP is robust and adapts under dynamic network conditions (topology or link cost changes) to maintain loop-free multicast routing. Under stable network conditions, MIP has no maintenance or control message overhead. We prove that MIP is loop-free at every instant, and that it is deadlock-free and obtains multicast routing trees within a finite time after the occurrence of an arbitrary sequence of topology or unicast changes     

WSNSec: A scalable data link layer security protocol for WSNs

A Wireless Sensor Network (WSN) link layer security protocol called WSNSec is proposed in this paper. The effective usage of limited sensor node resources is of high importance in WSN security protocol design and implementation. In addition, research on increased security for the WSNs employed in especially military and health areas recently receives a remarkable attention as primarily focused on in this presented work. The WSNSec smoothly combines the advantageous aspects of the Scalable Encryption Algorithm (SEA) with the Counter Mode (CTR) and Cipher Block Chaining-Message Authentication Code (CBC-MAC) approaches. It provides not only high data confidentiality but also message authentication and integrity functions. The WSNSec security level can be boosted dynamically if required. It has been shown that using the proposed WSNSec with the 192-bit data block/key size has a trivial increase on the memory usage and energy consumption while providing an extremely high level of security compared to the traditional TinySEC. In addition, modeling and simulation of a WSN employing the proposed WSNSec have been realized using the OPNET Modeler software. The simulation results reveal that the ratios of the delays resulted from the particular use of both WSNSec and TinySEC to the total end to end delays converge at 13% for increasing the network load. Therefore the WSNSec provides a better delay performance in highly scalable applications.     

一种具有可扩展性的RFID标签轻量级组证明协议

组证明(Grouping-proof)协议的目的是证明阅读器扫描范围内待扫描标签组内标签是否同时存在。随着标签组和组内标签数量的增长,协议中存在的计算时间复杂度、通信总量、组证明生成机制和标签干扰等制约扩展性的因素严重影响了生成有效组证明的成功率。通过比较分析相关协议,设计了一个适用于大规模标签组的只需简单异或和伪随机运算的轻量级组证明协议。在相同的假设模型下,协议能抵抗常见安全攻击,满足强隐私特性的同时,符合超高频段低成本被动式标签的硬件成本要求,具有更高的执行效率。     

Power aware scalable multicast routing protocol for MANETs

Multicasting is an effective way to provide group communication. In mobile ad hoc networks (MANETs), multicasting can support a wide variety of applications that are characterized by a close degree of collaboration. Since MANETs exhibit severe resource constraints such as battery power, limited bandwidth, dynamic network topology and lack of centralized administration, multicasting in MANETs become complex. The existing multicast routing protocols concentrate more on quality of service parameters like end‐to‐end delay, jitter, bandwidth and power. They do not stress on the scalability factor of the multicast. In this paper, we address the problem of multicast scalability and propose an efficient scalable multicast routing protocol called ‘Power Aware Scalable Multicast Routing Protocol (PASMRP)’ for MANETs. PASMRP uses the concept of class of service with three priority levels and local re‐routing to provide scalability. The protocol also ensures fair utilization of the resources among the nodes through re‐routing and hence the lifetime of the network is increased. The protocol has been simulated and the results show that PASMRP has better scalability and enhanced lifetime than the existing multicast routing protocols. Copyright © 2005 John Wiley & Sons, Ltd.     

Distributed cache updating for the dynamic source routing protocol

On-demand routing protocols use route caches to make routing decisions. Due to mobility, cached routes easily become stale. To address the cache staleness issue, prior work in DSR used heuristics with ad hoc parameters to predict the lifetime of a link or a route. However, heuristics cannot accurately estimate timeouts because topology changes are unpredictable. In this paper, we propose proactively disseminating the broken link information to the nodes that have that link in their caches. We define a new cache structure called a cache table and present a distributed cache update algorithm. Each node maintains in its cache table the information necessary for cache updates. When a link failure is detected, the algorithm notifies all reachable nodes that have cached the link in a distributed manner. The algorithm does not use any ad hoc parameters, thus making route caches fully adaptive to topology changes. We show that the algorithm outperforms DSR with path caches and with Link-MaxLife, an adaptive timeout mechanism for link caches. We conclude that proactive cache updating is key to the adaptation of on-demand routing protocols to mobility.     

A resource-efficient and scalable wireless mesh routing protocol

By binding logic addresses to the network topology, routing can be carried out without going through route discovery. This eliminates the initial route discovery latency, saves storage space otherwise needed for routing table, and reduces the communication overhead and energy consumption. In this paper, an adaptive block addressing (ABA) scheme is first introduced for logic address assignment as well as network auto-configuration purpose. The scheme takes into account the actual network topology and thus is fully topology-adaptive. Then a distributed link state (DLS) scheme is further proposed and put on top of the block addressing scheme to improve the quality of routes, in terms of hop count or other routing cost metrics used, robustness, and load balancing. The network topology reflected in logic addresses is used as a guideline to tell towards which direction (rather than next hop) a packet should be relayed. The next hop is derived from each relaying node’s local link state table. The routing scheme, named as topology-guided DLS (TDLS) as a whole, scales well with regard to various performance metrics. The ability of TDLS to provide multiple paths also precludes the need for explicit route repair, which is the most complicated part in many wireless routing protocols. While this paper targets low rate wireless mesh personal area networks (LR-WMPANs), including wireless mesh sensor networks (WMSNs), the TDLS itself is a general scheme and can be applied to other non-mobile wireless mesh networks.     

A scalable mobile host protocol for the internet

This paper describes a new Mobile IP protocol supporting wide area network. This protocol named Scalable Mobile IP (SMIP) allows any mobile host to move inside a large‐scale area while being transparently connected to the Internet using its permanent IP address. Copyright © 2000 John Wiley & Sons, Ltd.     

SRCP: sharing and reuse-aware replacement policy for the partitioned cache in multicore systems

Although multi-core processors enhance the performance yet the challenge of estimating Worst-Case Execution Time (WCET) of a task remains in such systems due to interference in shared resources like Last Level Caches (LLC). Cache partitioning has been used to reduce the interference problem by isolating the shared cache among each thread to ease the WCET estimation. However, it prevents information shared among parallel threads running in different cores. In current work, we propose sharing and reuse aware partitioned cache (SRCP) framework such that replication of shared information, data, or instruction, in different partitions could be avoided in LLC. Further, enhancement in existing cache replacement policy is proposed, which avoids eviction of cache blocks shared among multiple cores accessing partitioned last level cache. Tighter WCET, as well as improved resource utilization, is thereby ensured with the proposed framework. Experimental results show that SRCP shows significant improvement in cache hit-rate for PARSEC and SPLASH2 benchmarks as compared to least recently used cache replacement policy and outperforms EHC and TA-DRRIP, which are state-of-the-art replacement policies.

     

基于IGRS协议的多媒体共享系统

文中提出了一种基于闪联协议的家庭多媒体共享系统的设计与实现方法,该系统的目标是实现家庭网络内不同信息设备的互联互通、资源共享及协同服务.本系统以家庭网关作为中心节点,通过闪联协议实现家庭设备间的自动发现和互联互通,并调用闪联协议的AV智能应用框架实现了设备间的媒体资源共享.文中在介绍闪联协议及AV应用框架的基础上,重点阐述闪联设备的信息交互、共享系统的构成,并实现了相关的功能模块.     

A scalable multicast routing protocol for building shortest path trees

Scalability is a great concern in the design of multicast routing protocols for the global Internet. Building shortest path trees (SPT) is currently one of the most widely used approaches to supporting multicast routing because of the simplicity and low per‐destination cost of such trees. However, the construction of an SPT typically involves high protocol overhead, which leads to the scalability problem as the number of concurrent multicast sessions increases. In this paper, we present a destination‐initiated shortest path tree (DSPT) routing protocol. The design objective is to effectively reduce the protocol overhead associated with SPT constructions for providing scalable multicast. To achieve this objective, we introduce destination‐initiated joining operations in constructing SPTs. With DSPT, each router receiving a request to join a specific multicast group makes a local decision on selecting its parent node through which it connects to the existing tree. A source‐rooted SPT is built as a result of such collaborative operations at nodes. DSPT requires only limited routing information at routers. Analytical results demonstrate that DSPT scales well with respect to computation, storage and communication overhead when the number of concurrent multicast requests is large. Simulation experiments are also conducted to verify the correctness of the theoretically deduced analytical results. Copyright © 2006 John Wiley & Sons, Ltd.     

A scalable distributed dynamic address allocation protocol for ad-hoc networks

Dynamic address allocation is an essential part in effective configuration and maintenance of a mobile ad-hoc network (MANET). In this paper, we present a new distributed dynamic address allocation protocol minimizing address allocation latency and communication overhead. Through analytic evaluation and experimental measurements, we show that scalability and faster recovery from failures can be achieved by dynamic address allocation. The dynamic address assignment protocol presented here requires a low memory footprint while supporting unicast, broadcast and multicast communication. A performance analysis of the proposed address allocation protocol is given in terms of address allocation latency and communication overhead. Node and Network mobility is addressed from the point of dynamic address management. The dynamic address allocation protocol is implemented on a TinyOS platform over a cluster tree network.     

秘密共享新个体加入协议的安全性分析与改进

针对一个秘密共享新个体加入协议,具体地给出了2种攻击,使得不良的广播接收者可以很容易的恢复出t个旧成员的秘密份额Si,进而恢复出新个体的秘密份额Sn+1和主秘密S,并且证明了导致这2种攻击成功的根本原因.此外,提出了一个新的改进方案,改进方案不仅弥补了原方案的安全缺陷,而且与已有的协议相比需要更少的通信量.     

Blazenet: a packet-switched wide-area network with photonic datapath

A packet-switching network with photonic data path, Blazenet, that provides low delay and has minimal memory requirements is described. It can be extended to support multicast and priority delivery. The Blazenet design is described, addressing the issues of packet-switching and traffic congestion. A detailed switching node design is presented. Extended features that can be incorporated into Blazenet's design-priority traffic, limiting packet lifetime, and broadcast and multicast-are described. Some issues of the higher layers that have direct implication on Blazenet's operation are presented