Mobile computing environments that seek to support communication-intensive applications need to provide sustained end-to-end networking resources to static and mobile ows in the presence of scarce and variable wireless bandwidth, bursty wireless channel error, and user mobility. In order to achieve this goal, we present the TIMELY adaptive resource management architecture and algorithms for resource reservation, advance reservation, and network layer and end-to-end adaptation in mobile computing environments. The key novelty of our approach is the coordination of adaptation between the di erent layers of the network in order to solve the problems introduced by scarce and dynamic network resources.

In this paper, we propose a novel approach for effectively supporting multimedia packet flows in an Internet environment. The following are the key contributions of this paper: (a) we propose a new transport protocol called HPF that supports multiple interleaved reliable and unreliable data sub-streams, (b) we decouple the congestion control and reliability mechanisms that are integrated in TCP -this allows us to provide congestion control for unreliable streams as well as reliable streams, and (c) we use priorities within sub-streams of a packet flow as application-defined hints for the link level scheduler to drop packets during congestion.We show through performance measurements in our experimental testbed that our approach can provide effective support for heterogeneous packet flows in the presence of dynamic networking resources.

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Absrracr-IRMA is a reliable multicast architecture that guarantees reliable, sequenced, and loosely synchronized delivery of multicast streams. IRMA provides ACK-based reliability, hybrid local server-initiated and sender-initiated loss recovery, and support for end-to-end Bow control and congestion control. Unlike most contemporary work, IRMA supports TCP as the reliable multicast transport protocol at the end host without modifications. IRMA has been instantiated in a laboratory testbed, and its performance has been measured in various scenarios. Preliminary performance results show that IRMA is efficient and adaptive to the dynamics of the network. 0-7803-5417-6/99/$10.00 0 1 999 IEEE.

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