Haiyong Xie

P4p: provider portal for applications

As peer-to-peer (P2P) emerges as a major paradigm for scalable network application design, it also exposes significant new challenges in achieving efficient and fair utilization of Internet network resources. Being largely network-oblivious, many P2P applications may lead to inefficient network resource usage and/or low application performance. In this paper, we propose a simple architecture called P4P to allow for more effective cooperative traffic control between applications and network providers. We conducted extensive simulations and real-life experiments on the Internet to demonstrate the feasibility and effectiveness of P4P. Our experiments demonstrated that P4P either improves or maintains the same level of application performance of native P2P applications, while, at the same time, it substantially reduces network provider cost compared with either native or latency-based localized P2P applications.

Optimizing cost and performance for multihoming

Multihoming is often used by large enterprises and stub ISPs to connect to the Internet. In this paper, we design a series of novel smart routing algorithms to optimize cost and performance for multihomed users. We evaluate our algorithms through both analysis and extensive simulations based on realistic charging models, traffic demands, performance data, and network topologies. Our results suggest that these algorithms are very effective in minimizing cost and at the same time improving performance. We further examine the equilibrium performance of smart routing in a global setting and show that a smart routing user can improve its performance without adversely affecting other users.

COPE: traffic engineering in dynamic networks

Traffic engineering plays a critical role in determining the performance and reliability of a network. A major challenge in traffic engineering is how to cope with dynamic and unpredictable changes in traffic demand. In this paper, we propose COPE, a class of traffic engineering algorithms that optimize for the expected scenarios while providing a worst-case guarantee for unexpected scenarios. Using extensive evaluations based on real topologies and traffic traces, we show that COPE can achieve efficient resource utilization and avoid network congestion in a wide variety of scenarios.

Efficient and dynamic routing topology inference from end-to-end measurements

Inferring the routing topology and link performance from a node to a set of other nodes is an important component in network monitoring and application design. In this paper, we propose a general framework for designing topology inference algorithms based on additive metrics. The framework can flexibly fuse information from multiple measurements to achieve better estimation accuracy. We develop computationally efficient (polynomial-time) topology inference algorithms based on the framework. We prove that the probability of correct topology inference of our algorithms converges to one exponentially fast in the number of probing packets. In particular, for applications where nodes may join or leave frequently such as overlay network construction, application-layer multicast, and peer-to-peer file sharing/streaming, we propose a novel sequential topology inference algorithm that significantly reduces the probing overhead and can efficiently handle node dynamics. We demonstrate the effectiveness of the proposed inference algorithms via Internet experiments.

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.

On self adaptive routing in dynamic environments - an evaluation and design using a simple, probabilistic scheme

Recently we have seen an emergent trend of self adaptive routing in both Internet and wireless ad hoc networks. Although there are previous methods for computing the traffic equilibria of self adaptive routing (e.g., selfish routing), these methods use computationally demanding algorithms and require that a precise analytical model of the network be given. Also, it remains an open question how to design an adaptive routing scheme which ensures convergence to traffic equilibria in practice. In this paper we propose a simple, efficient, distributed probabilistic routing scheme for self adaptive routing in dynamic, realistic environments. Using both analysis and extensive simulations, we show that our scheme can converge to the desired traffic equilibrium (either user-optimal or network-optimal) very quickly. We find that user-optimal routing can achieve very close to optimal average latency in dynamic environments, but such performance often comes at the cost of seriously overloading certain links. To avoid link overloads, we improve adaptive routing by optimizing average user latency and link utilization simultaneously. Our evaluation shows that there is a trade-off between optimizing dual objectives, but the degradation in average latency is only marginal for typical link utilization requirements.

Network Routing Topology Inference from End-to-End Measurements

Inference of the routing topology and link performance from a node to a set of other nodes is an important component of network monitoring and application design. In this paper we propose a general framework for designing topology inference algorithms based on additive metrics. Our framework allows the integration of both end-to-end packet probing measurements and traceroute type measurements. Based on this framework we design several computationally efficient topology inference algorithms. In particular, we propose a novel sequential topology inference algorithm to address the probing scalability problem and handle dynamic node joining and leaving. We provide sufficient conditions for the correctness of our algorithms and derive lower bounds on the probability of correct topology inference. We conduct Internet experiments to evaluate and demonstrate the effectiveness of our algorithms.

Stable egress route selection for interdomain traffic engineering: model and analysis

We present a general model of interdomain route selection to study interdomain traffic engineering. In this model, the routing of multiple destinations can be coordinated. Thus the model can capture general traffic engineering behaviors such as load balancing and link capacity constraints. We first identify potential routing instability and inefficiency of interdomain traffic engineering. We then derive a sufficient condition to guarantee convergence. We also show that the constraints on local policies imposed by business considerations in the Internet can guarantee stability without global coordination. Using realistic Internet topology, we evaluate the extent to which routing instability of interdomain traffic engineering can happen when the constraints are violated

Towards an ISP-compliant, peer-friendly design for peer-to-peer networks

Peer-to-peer (P2P) applications are consuming a significant fraction of the total bandwidth of Internet service providers (ISPs). This has become a financial burden to ISPs and if not well addressed may lead ISPs to block or put strict rate limits on P2P traffic. In this paper, we propose a new framework, PCP, for designing P2P applications to smoothly fit into the global Internet. In our framework, an ISP decides on how much of its bandwidth is to be allocated to P2P clients, and P2P clients inside the network adopt a peer-friendly algorithm to fairly share the bandwidth. Using the widely-used percentile-based charging model and real traffic traces, we show that an ISP can allocate a large amount of bandwidth dedicated to P2P, without increasing its financial cost. We also show that P2P clients can use the algorithm to fairly share the allocated bandwidth.

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.