4379994
Interdomain Routing as Social Choice
Interdomain routing is essential to both the stability and efficiency of the global Internet. However, most previous studies focus only on stability, and only on a special class of routing protocols, namely BGP-type, path-vector protocols. In this paper, we conduct a systematic analysis of interdomain routing considering optimality and implementation in strategic settings. We adopt the novel perspective that an interdomain routing system is one which defines a social choice rule that aggregates individual preferences of all of the autonomous systems (ASes) in a network to select interdomain routes with a set of desirable properties. An interdomain routing protocol, then, is a mechanism to implement the identified interdomain routing social choice rule, when the ASes can adopt strategic actions. By pointing out the incompatibility among the desirable properties of an interdomain routing system and the requirements for strategic implementation in distributed settings, we reveal fundamental tradeoffs that must be made when extending BGP or designing the next-generation interdomain routing system. We also provide new insights into BGP, by "reverseengineering" its behaviors from the perspective of social choice and implementation theory.
10887794
Packet doppler: network monitoring using packet shift detection
Due to recent large-scale deployments of delay and loss-sensitive applications, there are increasingly stringent demands on the monitoring of service level agreement metrics. Although many end-to-end monitoring methods have been proposed, they are mainly based on active probing and thus inject measurement traffic into the network. In this paper, we propose a new scheme for monitoring service level agreement metrics, in particular, delay distribution. Our scheme is passive and therefore will not cause perturbation to real traffic. Using realistic delay and traffic demands, we show that our scheme achieves high accuracy and can detect burst events that will be missed by probing based methods.
9852672
NXG06-6: On the Efficient Implementation of Pipelined Heaps for Network Processing
Priority queues are often used in many network processing applications. Applications include sophisticated per-flow scheduling for providing advanced quality-of-service (QoS) guarantees, fast packet buffer memory management, and exact maintenance of statistics counters for real-time network measurements. In all these applications, the priority queues used must operate at very high-speeds, e.g. at 40 Gbps rates and beyond. One widely used data structure for implementing priority queues is the heap data structure. However, the logarithmic time complexity of heap operations is often too slow for increasingly fast line rates. To achieve constant time complexity, the pipelined heap structure has been proposed. In this paper, we describe new architecture techniques for the efficient implementation of pipelined heaps. In particular, we focus on aggressive memory management and pipelining techniques.
4427518
On the stability of rational, heterogeneous interdomain route selection
The recent discovery of instability caused by the interaction of local routing policies of multiple ASes has led to extensive research on the subject. However, previous studies analyze stability under a specific route selection algorithm. In this paper, instead of studying a specific route selection algorithm, we study a general class of route selection algorithms which we call rational route selection algorithms. We present a sufficient condition to guarantee routing convergence in a heterogeneous network where each AS runs any rational route selection algorithm. Applying our general results, we study the potential instability of a network where the preference of an AS depends on not only its egress routes to the destinations but also its inbound traffic patterns (i.e., the distribution of incoming traffic from its neighbors). We show that there exist networks which will have persistent route oscillations even when the ASes strictly follow the constraints imposed by business considerations, and adopt any rational route selection algorithms.
36787117
Parallelizing Support Vector Machines on Distributed Computers
Support Vector Machines (SVMs) suffer from a widely recognized scalability problem in both memory use and computational time. To improve scalability, we have developed a parallel SVM algorithm (PSVM), which reduces memory use through performing a row-based, approximate matrix factorization, and which loads only essential data to each machine to perform parallel computation. Let n denote the number of training instances, p the reduced matrix dimension after factorization (p is significantly smaller than n), and m the number of machines. PSVM reduces the memory requirement from O(n2) to O(np/m), and improves computation time to O(np2/m). Empirical study shows PSVM to be effective. PSVM Open Source is available for download at http://code.google.com/p/psvm/.
4409694
On route selection for interdomain traffic engineering
In this article we investigate a model of route selection for interdomain traffic engineering where routing to multiple destinations can be coordinated. We identify potential routing instability and inefficiency problems, and derive a set of practical guidelines to guarantee stability without global coordination. Using a realistic Internet topology, we show that route oscillations can happen even when a small number of ASes coordinate route selection for just a small number of destinations if the coordination does not follow our guidelines. Wc further extend our model so that ASes can adopt any route selection algorithms in a class of algorithms we call rational route selection algorithms; and the local ranking of routes of an AS can depend on ingress traffic patterns. We show that persistent route oscillations can happen in certain network settings even if the ASes strictly follow the constraints imposed by business considerations, and adopt any rational route selection algorithms.
23849852
Radius Restrained Distributed Breadth First Search Flooding in Large-Scale Multimedia Communication
This paper proposed an algorithm of radius restrained distributed breadth first search flooding for call routing in multimedia communication. By knowing the information of neighbor nodes in finite scope, this algorithm does breadth first search and selects the least number of next forwarding neighbor nodes to reduce redundant information in broadcasting routing information. Simulation results demonstrate that the proposed algorithm lessens the average forwarding times and shortens the delay in transferring routing information. Especially, it can decrease the redundant information to the greatest extent in large scale multimedia communication.
5494803
Wireless Network Dynamic Topology Routing Protocol Based on Aggregation Tree Model
As the scale of the network increases, especially wireless and mobile networks comes into fashion, the problem of network dynamic topology management turns into a focus topic in the network world. When network information changes, frequent route computing and network state updates can cause computing and traffic overhead, respectively. Therefore, minimum of influence to network structure has been identified as one of the key issues in designing dynamic network routing protocols. A novel protocol, which is based on Aggregation Tree Routing Model (ATRM) as well as an effective ball-and-string algorithm, is introduced in this paper which aims to minimize the alteration of network topology and to speed up the minimum cost route computation. This routing protocol is applicable to all kinds of networks, including Internet, ad hoc and wireless sensor networks. The simulations show that our protocol not only results in significantly lower overhead, but also gives high levels of dynamic network topology management performance while keeping practical.
5812455
Knowledge Enhanced IT Service Management
To manage the increasing complexity of IT systems and align IT services with business is the main theme of IT Service Management (ITSM). Current ITSM architecture adopts ITU as the framework to integrate silos of operational management tools and configuration information to build an end-to-end solution based on best practices. However, it lacks of a systematic means to address an important aspect of IT operation, i.e., managing the knowledge separated in various tools and experts' minds. In this paper, a novel knowledge-enhanced architecture is proposed to improve the effectiveness and efficiency of ITSM. The essential contribution of this novel architecture is to involve a Knowledge Management Database (KMDB) which provides assistance for knowledge capture, mining, storage and sharing. The paper will discuss an approach of how to construct such a KMDB with motivating scenarios and detailed description of key components. To validate the approach, a prototype system is developed and evaluated by being applied for problem analysis on a Cisco Voice over IP (VoIP) system. The experiment results show a remarkable improvement in the effectiveness and efficiency for practical IT service management operations.
10659233
Wiener indices of balanced binary trees
We study a new family of trees for computation of the Wiener indices. We introduce general tree transformations and derive formulas for computing the Wiener indices when a tree is modified. We present several algorithms to explore the Wiener indices of our family of trees. The experiments support new conjectures about the Wiener indices.
14899060
Automatic model-based service hosting environment migration
The proper operation of Service-Oriented Architecture (SOA) depends on underlying system services of operating systems, so efficient and effective migration of Service Hosting Environment is critical to cope with intrinsic-changed nature of SOA. However, due to the large amount of configuration items, complicated mapping and complex dependency relationship among system services, migrating into a new Service Hosting Environment satisfying the operation requirement of SOA becomes an error-prone and time-consuming task. The SCM project in IBM develops a novel approach to migrate Service Hosting Environment shaped in Unix-like systems. Firstly, this approach builds a set of configuration models to describe various system services. Then based on models, it presents knowledge based mapping to translate system service configurations between Service Hosting Environments. Finally, it designs a dependency hierarchy deducting algorithm to compute the dependency relationship among system services for migration traceability and error determination. A SCM prototype has performed well on largely reducing time, labor and errors in real migration cases.