Bengt Ahlgren

A Node Identity Internetworking Architecture

The Internet consists of independent networks that belong to different administrative domains and vary in scope from personal area networks, private home networks, corporate networks to ISP and global operator networks. These networks may employ different technologies, communications mediums, addressing realms and may have widely different capabilities. The coming years will add a significant level of dynamic behavior, such as mobile nodes and moving networks, which the Internet must support. At the same time, there is a need to address the increasing levels of harmful traffic and denial-of-service attacks. The existing Internet architecture does not support dynamic behavior or secure communication to a sufficient degree. This paper outlines a node-identity-based internetworking architecture that allows heterogeneous networks to work together without loss of functionality. Some of techniques employed in this architecture include reliance on cryptographic node identifiers, identity routers and localized addressing realms.

The Impact of Wakeup Schedule Distribution in Asynchronous Power Save Protocols on the Performance of Multihop Wireless Networks

By definition, the operation of an asynchronous power save protocol permits an arbitrary distribution of nodes wakeup schedules. This wakeup schedule distribution creates an uncoordinated pattern of times at which nodes attempt to transmit. Intuitively, we would expect that some patterns are more (or less) favorable than others for a given traffic pattern. We investigate the impact of this wakeup pattern on network capacity and present simulation data showing that the capacity associated with the best wakeup patterns is significantly larger than that of the worst. This result not only gives insight to the behavior of such protocols, but also acts as a feasibility study showing the potential benefit of mechanisms by which nodes adapt their wakeup schedules to obtain improved performance.

The applicability of integrated layer processing

We review previous work on the applicability and performance of integrated layer processing (ILP). ILP has been shown to clearly improve computer communication performance when integrating simple data manipulation functions, but the situation has been less clear for more complex functions and complete systems. We discuss complications when applying ILP to protocol stacks, the requirements of ILP on the communication subsystem, caching aspects, the importance of the processor registers, and a model for predicting the performance of data manipulation functions. We conclude that the main drawback of ILP is its limited applicability to complex data manipulation functions. The performance to expect from an ILP implementation also depends heavily on the protocol architecture and the host system architecture.

Leveraging a power save protocol to improve performance in ad hoc networks

Power save protocols reduce energy consumption in ad hoc and sensor networks by allowing nodes to put their network interface into a low power consumption sleep state. The power save protocol must allow neighboring nodes to establish intervals during which they are mutually awake and available to exchange traffic. Many such protocols are based on a coordinated election of a covering set that is responsible for buffering traffic for sleeping nodes, but uncoordinated (i.e. asynchronous) protocols have also proven an attractive option.