These are projects that I am actively working on, and that I foresee working on for some time before I am ready to call them either completed or dormant. Typically one or more funded students are working on each of these.
I was one of 5 Co-PI’s (lead: Dr. Ismail Guvenc of ECE) who developed a proposal submitted in August 2018 to NSF’s PAWR program, and shepherded it over the next year, until it was awarded in September 2019, to build a national testbed on the outdoor areas of the Centennial and Lake Wheeler campuses of NC State, as well as specific areas outside NC State grounds in Raleigh and Cary. The project is in its early stages, and is expected to take 3 years to fully build out, and 2 more years to fully operationalize. It will be a testbed incorporating programmable UAVs, programmable radios, and programmable networks, and will be remotely accessed by both industry and academia researchers nationwide. More details of this unique project may be found at the AERPAW project website.
Aerial Geographic Routing
When a standalone ad-hoc or peer-to-peer network comprises some or all wireless nodes that change position, or the mobile clients of some infrastructure wireless network engage in peer-to-peer sidehaul, geographic routing is a good technique to reduce broadcast overhead. When the mobile nodes move into the air, and different ones zip along at distinctly different speeds, the added challenges make this problem worth revisiting. Research problems in this space include studying the efficacy of the 3D generalizations of existing 2D geographic routing algorithms, techniques to improve them, including typical spatial variations of infrastructure-provided connectivity in the study, and trajectory design in support of network maintenance.
Areas for Upcoming Research
This is the section I use to note down research projects and problems I have been formulating and am ready to embark on, or apparently-promising ideas I get in the middle of the night, or anything inbetween. Thus they range from well-considered roadmaps to vague ramblings. If something strikes you as making no sense, that may be because it does not.
By definition, this section is perpetually under construction. Depending on when you came here, there might not be much here; hopefully there will be soon, check back.
The newly emerging paradigm called Software Defined Networking encompasses many areas of networking innovation, many of which are previously existing ones, but have come together under the SDN umbrella to provide new perspectives in light of the software and hardware technology capabilities of the day, as well as the economic and social realities. The concept of SDN is also closely related with network virtualization, and recent concepts such as NFV. Depending on who you ask, SDN will change the world / has changed the world / is irrelevant / there’s no such thing.
The truth is probably “out there” in the future where it is not quite accessible yet, but this much is true: programmers love to program, consumers love features, and features that result from complex programming and reduce cost are irresistible. SDN, NFV, VNF, SFC, OF, P4, ORAN, are all geared toward programming more flexible and cost-effective control of more flexible networking. Lots of research questions relate to the new opportunities and new challenges that arise from more softwarized data, control, and management planes of the network.
ORAN is probably the latest incarnation of SDN, and its practical incursion into the wireless networking space. That, and P4 (the latest incarnation of SDN in the wired backbone) are currently my areas of interest in SDN.
What happens when computers that are network endpoints fly around in the air? What happens to the network characteristics? What if the command and control coordination of the flying vehicles itself depends on network continuity? Can such systems continue to work well even if the network loses packets? What about the security of such a network, and such aerial networking endpoints? What if they are not just endpoints, but routers? Or firewalls – can you even have a Flying Firewall?
Aerial networking will be a rich source of research questions for several years, if not several decades, in the near future.
Identity, Trust, Confidence in IoT Systems
In IoT systems of the most general descriptions, multiple agents representing multiple different (and usually at least partly conflicting) interests of multiple stakeholders interact cyber-physically, and are at least partly mutually dependent. In such a context, it cannot be assumed that all agents have a priori trust or other relationships with each other, but they have to be able to depend on the information provided by each other, often for safety. Creating a framework in which such interactions can dependably proceed seems like an interesting research challenge.
Completed / Dormant Projects
This section lists projects of significance that are not active at this time. In some cases, they are related to the work performed on a particular grant, which defined the scope of the work – so the project is considered “complete” even though my students may still be engaged in research on related topics. In other cases, the project is not attached to a particular grant, but may have been funded from various sources at various times, or unfunded in part; in that case, I consider it a “project” if it encompasses a distinct collection of highly related research.
Not all the research done by all my students is represented in here – not all thesis work is a “project” or part of one. That is why we have dissertations and publications – which after all are more important than my arbitrary organization here. By no means is it implied that the past research of my former students that is not represented in this organization is any the less important.
As with all research, these projects are dormant rather than ended; any of these areas could be topics for further research at a future time – although this is only likely for the first two entries below.
ChoiceNet is the name of an architectural vision to support choice as the central aspect of the Internet architecture. This was funded by a large multi-university grant from NSF in 2010 under the umbrella of its new program Future Internet Architecture (FIA) – this program has only funded 5 research projects, see the NSF FIA website for the others. Our project was called ChoiceNet – we postulated that fine-grain innovation in networking services can be encouraged by integrating a framework for accountable allocation of customer’s expenditure, targeted measurement of performance, and selective re-composition of the service needed by the customer based on satisfaction of user expectation. We proposed an initial set of architectural building blocks to achieve these goals, such that they could be integrated in not only the current Internet architecture, but a wide variety of other possible architectures, such as those being proposed by the FIA community. News of this grant was covered by National Public Radio (WUNC) in November, 2011, on the “All Things Considered” program, including quotes from Dr. Dutta and other PIs from NCSU and UNC-CH. The following ChoiceNet website provides somewhat more detailed information.
A particular thread of research in optical networking that is concerned with the efficient assignment of traffic demands to available network bandwidth became known as traffic grooming in the mid-1990’s. Initially motivated by the distinctly different network characteristics of optical and electronic communication channels, the area focused on how sub-wavelength traffic components were to be mapped to wavelength communication channels, such that the need to convert traffic back to the electronic domain at intermediate network nodes, for the purpose of differential routing, was minimized.
The quantum jump in transmission speed due to the use of fiber was not matched by a similar improvement in processing speed at intermediate network processing elements (routers, switches), and as computational speeds go up, so does throughput. As a consequence, a mismatch in the rates of transmitting traffic and processing traffic has persisted. Either the fiber has to be severely underutilized (not a preferable solution, and not viable in the long run), or many processing elements have to be deployed to conventionally route/switch at each intermediate (network interior) node. This latter solution can be prohibitively expensive. In addition, the processing equipment is all electronic, thus delay is incurred in electro-optic conversion every time the packets/cells contained in an optical signal must be routed. This will usually be necessary because the bandwidth of even a single wavelength is likely to be much larger than the typical user channel bandwidth, thus many slower speed traffic streams will be multiplexed (probably TDM) over each wavelength channel. It becomes very attractive to allow some (hopefully the bulk) of the traffic to be switched optically, using wavelength routing, and resort to electro-optic conversion and electronic processing only when it cannot be avoided. This problem has been called traffic grooming in literature. In the general case, as well as in many quite restrictive cases of topology and traffic patterns, this problem is computationally intractable.
Grooming continues to be an active research area, and it has come to be seen as a general study of techniques in network conditioning to reconcile traffic and network mismatches due to various considerations – for example, Green Grooming attempts to revisit the problem, and reuse grooming techniques, to minimize energy consumption in backbone networks. Over the years, I have worked with many students on various topics related to grooming. Please see my 2007 and 2002 surveys on grooming, and also the book I co-edited in 2008. My chapter in the 2020 Springer Handbook of Optical Networking may be the best quick introduction to traffic grooming I can recommend.
As of Fall, 2019, CentMesh has been absorbed into the current (and much more ambitious) AERPAW project described above. Below is some historical information on CentMesh.
In Spring 2012, an effort I had been engaged in for several years before that completed the final phase, and the Centennial Wireless Mesh Testbed (CentMesh) was deployed for use by NCSU researchers and instructors. CentMesh is an outdoor, highly programmable, extensible, open testbed to support research and education on the design of wireless mesh networks, as well as IT systems and applications enabled by wireless mesh networks. It was conceived and designed by Dr. Mihail Sichitiu of the ECE department and myself, with foundational input and support from Associate Vice-Chancellor Dennis Kekas. The testbed was part of the vision included in the Secure Open Systems Initiative (SOSI) of which I was a PI, and subsequently, in 2009, we were awarded a Defense University Research Instrumentation Program (DURIP) funding from the Army Research Office to significantly increase the scope of this testbed. The NCSU Institute for Technology of the Next Generation (ITng) was in charge of the installation, operation and maintenance; Dr. Sichitiu and I continued to lead the research and teaching efforts.
Many emerging security and network research questions are in areas of network availability, reliability etc. Solutions are often proposed in research through routing, opportunistic MAC, adaptive power control, dynamic rate control and modulation, and other such research areas; these are all low down, or across traditional boundaries of, the networking stack. Commercially available wireless networking equipment do not allow experimentation at these detailed levels, and researchers are reduced to using commodity computing hardware and using them as wireless equipment.
We envisioned CentMesh, and subsequently architected and developed it, to provide a versatile wireless networking substrate that would be deeply programmable (to allow whatever research innovation it was called upon to support), but provide a flexible and modular interface (to allow a researcher to make specific changes in the programming relevant to the research without requiring to undertake a large software project). Further, it was architected to be extensible; the basis of ever more ambitious and powerful research enabling infrastructures to come, as researchers pursue evolving research directions, both guiding and contributing to the enhancement of CentMesh capabilities. CentMesh was thus a research infrastructure project that provided usable facilities, not a development project that produced a static platform.
More information can be found in the publications produced out of the CentMesh project. CentMesh was covered by The News and Observer – the daily paper of the Raleigh-Durham-Chapel Hill area. One brief clarification to the title of the archived news story (which attempts to capture the spirit of the story while staying within the brevity required of newspaper titles). CentMesh is a first in many ways, but it is obviously not the first outdoor Wi-Fi network. There are many commercial networks which do that, including the one that covers Raleigh downtown. There are also experimental outdoor WiFi testbeds. However, the combination of programmability, span, and complete researcher control of CentMesh was indeed unprecedented at the time, as far as we know.
For almost ten years after the first successful research use of CentMesh, the testbed supported research of various kinds, and we added functionality to it on an ongoing basis. Our vision of CentMesh expanded over time, and became one that incorporated IoT and edge-computing. This vision is now enabling the CentMesh project being folded into AERPAW, as mentioned above.
The Global Environment for Networking Innovation (GENI) was an initiative funded by NSF starting 2006-07 to provide a national resource to networking and computing researchers and educators. It was intended to be a virtual laboratory in which a wide variety of networking experiments can be performed, at national scale, by many research groups in parallel. As such, this testbed attempted to provide the capability to “slice”, or virtualize, all resources in the entire GENI network – this concept (and indeed the term “slice”) was introduced to the networking community by GENI. This was a tremendous challenge by itself, considering the national footprint of GENI. It was all the more complicated because the various resources in the GENI substrate were typically innovative and non-standard networking equipment in themselves – such as a sensor testbed in Oklahoma or a low-altitude radar network in Massachusets – and also under different ownership and management. These diverse resources as well as the available national bandwidth have to be “slivered”, and then “stitched”, to provide a seamless “slice” for a researcher – a network with national footprint made of real equipment but isolated from the networks of other GENI users.
To build this unprecedented facility, NSF funded BBN to set up the GENI Project Office (GPO), which in turn funded researcher groups to architect and develop parts of the whole. My Integrated Measurement Framework (IMF) project was one of these – the only one at NCSU that has been funded by GENI. Building GENI is an engineering exercise, but one that demands that experience and awareness in breadth of networking research inform it at every point, which is why GPO is funding various researchers and research groups to build GENI, rather than doing it all at BBN. GENI development followed the processes and standards of deliverables that are more typical of production-grade engineering.
More information about the actual project can be found at the IMF project wiki at GENI. In its last year, we designed the Measurement Plane messaging system for the instrumentation and measurement cluster of GENI. This formed a critical piece of both GEMINI and GIMI – the two redundant Instrumentation and Measurement architectures being developed for GENI (I was part of the GIMI effort).
GENI has continued to serve the Networking research and teaching community for over a decade. Some years ago, it has shifted to a fully operational mode, and ceased new development; for now, the outlook is that it will not shift into development again, but keep operating and eventually reach end-of-life. NSF has since then funded many other research infrastructures for broadly shared use. In a very real sense, GENI is the precursor for all of these.
In 2005, NSF issued a call for “clean-slate future Internet design” proposals – the Future Internet Design (FIND) solicitation. Our SILO project was one of the few teams to get funded in the very first cycle of this program. I am grateful not only for the actual funding, but for having had the opportunity to be a participant in a completely new re-examination of planetary networking architecture. In the SILO project, we envisioned networking functionality to be provided in fine-grain services in the protocol stack (at end-nodes, and within the network), with separate control interfaces for cross-service tuning and optimization. At special FIND events held by NSF, we collaborated with other FIND teams to inform their research with ours, and vice versa.
More information can be found in the papers published by the SILO project. The project ended after two years, with several publications as well as a working prototype proving the concept of our paradigm, and an REU supplement. However, the concepts we developed in SILO continued to influence our Internet architectural work – we have applied them both in the GENI-IMF project and ChoiceNet. More broadly, work done by the academic community such as in the SILO project was the conceptual precursor and to an extent progenitor of the micro-services framework that has become common in more recent times.
Science of Security
Late in 2011, the National Security Agency awarded Drs. Laurie Williams and Michael Rappa of NCSU Computer Science to set up a “lablet” – one of three that together make up a complete “virtual lab” to focus on the science of security. The other two component lablets are at University of Illinois at Urbana-Champaign and Carnegie Mellon University. The development of information security over the years has stressed the development of tools and algorithms to solve security problems, on the engineering and application of security. Together, the lablets attempt to articulate fundamental theoretical understanding of security as a science. Each lablet focuses on specific approaches – the NCSU lablet focuses on analytics. More information about the lablet is in the news release for the award, and on the websites of Drs. Williams and Rappa.
The NCSU lablet is pursuing various units of research aimed at security science topics, led by various researchers. I was engaged in two such units. The first is a project that addressed a specific collaborative approach for Sybil detection, suitable for sensor networks, that one of my students had previously worked upon. This project investigated the limits of applicability of such an algorithm, and obtained detection probabilities under various conditions. The second project I led was on attempting a scientific description of network security mechanisms as control systems. This project investigated specific network security systems by viewing them as feedback control systems, and attempting to determine general stability results or other characterization for them. Dr. Meeko Oishi from University of New Mexico was a co-PI on this project.
This project was jointly conducted by myself together with Dr. Mihail Sichitiu of the ECE department and Dr. Sami Rizkalla of the CCEE department of NCSU, in 2001-02. The goal of this project was to increase the lifetime of a battery-powered sensor network using a combination of scheduling and power aware routing for continuous monitoring sensor networks. The motivating application is structural health monitoring of building and bridges.
We developed algorithms to schedule sleep cycles of the sensors, to improve the lifetime of the network, to redistribute the energy of the network for maximum utilization, and to perform power-efficient routing. The final and highly relevant step for this project was the practical implementation of a signal pre-conditioning circuit featuring a programmable amplifier capable of variable range and resolution as well as temperature and non-linearity compensation. This was tested with actual bridge beams at the Constructed Facilities Laboratory at NCSU, with readings received remotely.