Amaranth: Probabilistically Guaranteed Quality of Service for Distributed Computing Systems

Overview
 

The Amaranth project will provide multi-dimensional, adaptive, assured Quality of Service (QoS) for heterogeneous distributed computing systems. In particular, Amaranth will enable systems to provide guarantees of QoS along multiple dimensions, with each dimension having several potential levels of potential assured service:

• Real-Time Deadlines: {hard deadlines, soft deadlines, best effort}
• Dependability: {modular redundancy, error correction, best effort}
• Cryptographic Security: {full encryption, digital signature, checksum}
• Application Performance (e.g., for videoconferencing): {full-motion video, stop-frame video, audio-only}

A main advantage of this approach is that Amaranth supports graceful degradation while still providing QoS guarantees. Assured graceful degradation may permit building smaller systems that are sized for average workloads, rather than requiring the construction of large systems sized for worst case conditions.

This program is expected to start during Summer 1997. In the first year the Amaranth architecture will be detailed, and a theoretical framework for multi-dimensional QoS will be adopted. Additionally, a prototype single-dimension QoS visualization tool will be created. By the end of the three-year project, both a multi-dimensional QoS visualization tool will be construction, and decentralized QoS algorithms will be developed. Further work may be sponsored based on contract options as shown in the schedule.

Architecture

Amaranth Components

Sessions Coordinator (SesCo)
Dependability Module (DMOD)
Forecasted Resource Utilization Module (FRUM)
Candidate Resource Selection
QoS-based Resource Allocation Module (Q-RAM)
Real-Time Queuing Theory (RTQT)
Resource Priority Multiplexing (RPM)
User Interface
Amaranth Simulator

Quad chart single-picture overview of Amaranth. The DARPA-format project summary is also available.