Shashidhar Merugu

Ulysses: a robust, low-diameter, low-latency peer-to-peer network†

A number of distributed hash table (DHT)-based protocols have been proposed to address the issue of scalability in peer-to-peer networks. In this paper, we present Ulysses, a peer-to-peer network based on the butterfly topology that achieves the theoretical lower bound of log n/ log log n on network diameter when the average routing table size at nodes is no more than log n. Compared to existing DHT-based schemes with similar routing table size, Ulysses reduces the network diameter by a factor of log log n, which is 2–4 for typical configurations. This translates into the same amount of reduction on query latency and average traffic per link/node. In addition, Ulysses maintains the same level of robustness in terms of routing in the face of faults and recovering from graceful/ungraceful joins and departures, as provided by existing DHT-based schemes. The performance of the protocol has been evaluated using both analysis and simulation. Copyright

Bowman: a node OS for active networks

Bowman is an extensible platform for active networking: it layers active networking functionality in user space software over variants of the System V UNIX operating system. The packet processing path implemented in Bowman incorporates an efficient and flexible packet classification algorithm, supports multi-threaded per-flow processing, and utilizes real time processor scheduling to achieve deterministic performance in the user-space. In this paper we describe the design and implementation of Bowman; discuss the support that Bowman provides for implementing execution environments for active networking; discuss the network-level architecture of Bowman that can be used to implement virtual networks; and present performance data showing that Bowman is able to sustain 100 Mbps throughput while forwarding IP packets over fast Ethernets.

Ulysses: a robust, low-diameter, low-latency peer-to-peer network

A number of distributed hash table (DHT)-based protocols have been proposed to address the issue of scalability in peer-to-peer networks. In this paper, we present Ulysses, a peer-to-peer network based on the butterfly topology that achieves the theoretical lower bound of (log n)/(log log n)on network diameter when the average routing table size at nodes is no more than log n. Compared to existing DHT-based schemes with similar routing table size, Ulysses reduces the network diameter by a factor of log log n. which is 2-4 for typical configurations. This translates into the same amount of reduction on query latency and average traffic per link/node. In addition, Ulysses maintains the same level of robustness in terms of routing in the face of faults and recovering from graceful/ungraceful joins and departures, as provided by existing DHT-based schemes. The performance of the protocol has been evaluated using both analysis and simulation.

Extending and enhancing GT-ITM

GT-ITM is a collection of software tools for creation, manipulation, and analysis of graph models of internet topology. It has been used by networking researchers in a variety of ways, most often to create topologies for use in simulation studies. This paper describes the features of a new release of GT-ITM, including enhanced visualization capabilities; a routing and forwarding module for use with large graphs; and support for modeling of interdomain routing policies.

P-sim: a simulator for peer-to-peer networks

In the past few years, there has been intense interest in designing and studying peer-to-peer networks. Many initial measurement studies on current deployed peer-to-peer networks attempted to understand their performance. However, the large size and complex nature of these networks make it difficult to analyze their properties. Simulation of these peer-to-peer networks enables a methodical evaluation and analysis of their performance. However, to our knowledge, there is no tool for simulating different peer-to-peer network protocols for a comparative study. We present p-sim: a tool that can simulate peer-to-peer networks on top of representative Internet topologies, p-sim has several capabilities to provide an accurate model of real-world peer-to-peer networks, p-sim can scale to thousands of nodes and is extensible to simulate new peer-to-peer network protocols. In this paper, we discuss the capabilities of p-sim, its user-interface and two case-studies.

Adding structure to unstructured peer-to-peer networks: the role of overlay topology

Our work examines the role of overlay topology on the performance of unstructured peer-to-peer systems. We focus on two performance metrics: (a) search protocol performance, a local gain perceived directly by a user of the system and (b) utilization of the network, a global property that is of interest to network service providers. We present a class of overlay topologies based on distance between a node and its neighbors. We show, by simulation, that a particular topology instance of this class where every node has many close neighbors and few random neighbors exhibits better properties than other examined instances. In this overlay topology, the chances of locating files are high and the nodes where these files are found are, on average, close to the query source. This improvement in search protocol performance is achieved while decreasing the traffic load on the links in the underlying network. We propose a simple greedy algorithm to construct such topologies where each node operates independently and in a decentralized manner.

CANEs: an execution environment for composable services

Active networks represent a change in network paradigm from a static, one-size-fits-all packet-transport service to a flexible platform capable of being programmed to provide new services. Active networks will allow rapid deployment of new and complex network services. An important property of an active network API is the support it provides for composing complex services out of components. An efficient and robust composition mechanism is essential for incremental development of useful services. We describe the CANEs Active Networking Environment. CANEs is an EE (Execution Environment) specifically built for composing services within the network. We discuss the design philosophy behind CANEs, describe the formal model which the composition mechanism is based upon, and detail the current CANEs implementation.