Network topology

About: Network topology is a research topic. Over the lifetime, 52259 publications have been published within this topic receiving 1006627 citations.

Tracking mobile users in wireless communications networks

Abstract: Tracking strategies for mobile wireless networks are studied. A cellular architecture in which base stations that are interconnected by a wired network communicate with mobile units via wireless links is assumed. The cost of utilizing the wireless links for the actual tracking of mobile users is considered. A tracking strategy in which a subset of all base stations is selected and designed as reporting centers is proposed. Mobile users transmit update messages only upon entering cells of reporting centers, while every search for a mobile user is restricted to the vicinity of the reporting center to which the user last reported. It is shown that, for an arbitrary topology of the cellular network (represented by the mobility graph), finding an optimal set of reporting centers is an NP-complete problem. Optimal and near-optimal solutions for important special cases of the mobility graph are presented. >

Network topology discovery systems and methods and their use in testing frameworks for determining suitability of a network for target applications

Abstract: A system discovers the topology of devices in a network, such as all of the layer-2 and layer-3 devices, including routers and switches. The devices are mapped, as well as the links that join them. The devices are polled using SNMP requests. Route tables are derived from each router to determine addresses of the devices. A spanning tree process is used to discover layer-2 devices. Connections between layers are then discovered. Where information is incomplete, an undiscovered router cloud is recognized.

Supporting virtual private networks using a first network topology for forwarding and a subset of the first network topology or a smaller topology for signaling

Abstract: Virtual Private Networks (VPNs) are supported in which customers may use popular internet gateway protocol (IGPs) without the need to convert such IGPs, running on customer devices to a single protocol, such as the border gateway protocol (BGP). Scaling problems, which might otherwise occur when multiple instances of an IGP flood link state information, are avoided by using a flooding topology which is smaller than a forwarding topology. The flooding topology may be a fully connected sub-set of the forwarding topology.

In search of path diversity in ISP networks

Abstract: Internet Service Providers (ISPs) can exploit path diversity to balance load and improve robustness. Unfortunately, it is difficult to evaluate the potential impact of these approaches without routing and topological data, which are confidential. In this paper, we characterize path diversity in the real Sprint network. We then characterize path diversity in ISP topologies inferred using the Rocketfuel tool. Comparing the real Sprint topology to the one inferred by Rocketfuel, we find that the Rocketfuel topology has significantly higher apparent path diversity.(As a metric, path diversity is particularly sensitive to the presence of false or missing links, both of which are artifacts of active measurement techniques.) We evaluate heuristics that improve the accuracy of the inferred Rocketfuel topologies. Finally, we discuss limitations of active measurements techniques to capture topological properties such as path diversity.

Location awareness in unstructured peer-to-peer systems

Abstract: Peer-to-peer (P2P) computing has emerged as a popular model aiming at further utilizing Internet information and resources. However, the mechanism of peers randomly choosing logical neighbors without any knowledge about underlying physical topology can cause a serious topology mismatch between the P2P overlay network and the physical underlying network. The topology mismatch problem brings great stress in the Internet infrastructure. It greatly limits the performance gain from various search or routing techniques. Meanwhile, due to the inefficient overlay topology, the flooding-based search mechanisms cause a large volume of unnecessary traffic. Aiming at alleviating the mismatching problem and reducing the unnecessary traffic, we propose a location-aware topology matching (LTM) technique. LTM builds an efficient overlay by disconnecting slow connections and choosing physically closer nodes as logical neighbors while still retaining the search scope and reducing response time for queries. LTM is scalable and completely distributed in the sense that it does not require any global knowledge of the whole overlay network. The effectiveness of LTM is demonstrated through simulation studies.