Faruk Volkan Mutlu PhD Dissertation defense

Name:
Faruk Volkan Mutlu

Title:
Cost-aware Joint Caching and Forwarding in Networks with Diverse Cache Resources

Date:
8/16/2024

Time:
10:30:00 AM

Committee Members:
Prof. Edmund Yeh (Advisor)
Prof. Stratis Ioannidis
Prof. Elif Uysal

Abstract:
The rapid growth of data-intensive applications is testing the limitations of today’s data distribution networks. Caching is a crucial tool for high performance in such networks, and a core principle in emerging paradigms like information-centric networking (ICN). In this dissertation, motivated by the needs of a landmark initiative addressing the networking challenges faced by large-scale scientific research programs, we focus on the key issue of expanding cache capacities in a cost-effective manner. While DRAM is still the standard cache device today due to its high transfer rates, its capacity is very limited and subject to contention by other networking functions. Large DRAM modules are also expensive, making wide area networks with cache-enabled routers costly to deploy. On the other hand, technologies like flash storage offer larger capacities at lower costs; observing recent advancements in this domain, we expect devices like NVMe SSDs to feature as additional cache tiers in networks supporting data-intensive applications. However, the slower transfer rates of such devices and the added operational costs they introduce pose some challenges.

This dissertation primarily focuses on the open problem of developing cost-aware caching policies that can effectively manage multiple types of cache available to routers. We begin by introducing an object-level multi-tiered caching model that incorporates the diverse characteristics of cache devices, namely their transfer rates and utilization costs. We then integrate this model with an established optimization framework to develop a joint caching and forwarding policy that uses caching resources available in the network intelligently to improve performance, minimize costs of cache utilization and avoid congestion. To highlight the advantages of our approach against adapted baselines, we conduct an exhaustive experimental evaluation of this policy under a large variety of simulation settings; we also provide a discussion of the event-driven object-level ICN simulator we built to facilitate this evaluation and support future research. Lastly, we also present a variation on our strategy that attempts to improve its efficiency under certain conditions by introducing new control variables into the aforementioned optimization framework.

This dissertation also discusses our work on the effective use of transmission and cache resources in wireless networks. While this work investigates a different context than that outlined above, it serves to complement our primary scope with a perspective on how caching can be leveraged in settings where resource constraints have a different type of interplay with network performance. Specifically, in the context of multi-hop wireless networks with arbitrary topologies and interfering transmissions, we study the open problem of delay minimization via caching subject to transmission power limitations. We cast this scenario as an optimization problem and highlight its analytical properties. We identify the challenges in finding a global optimum to the problem under general conditions, and propose an algorithm that converges to a local optimum. We conclude this discussion with numerical results that demonstrate the effectiveness of our approach.