Dirk Kutscher

Web applications today utilize the Representational State Transfer (REST) architecture pattern, depending on HTTP, TLS, and either TCP or QUIC as the protocol substrate to build upon. The resulting protocol stacks can be quite complex, and the RESTful communication is locked into channel-like connections of the respective transport protocol.

Given that most web applications are concerned with transferring named units of data (web resources, video chunks etc.), we asked ourselves: can the REST paradigm be married with the data-oriented, receiver-driven operation of Information-Centric Networking (ICN), leveraging attractive ICN benefits such as consumer anonymity, stateful and symmetric forwarding, flow-balance in-network caching, and implicit object security?

We argue that this is feasible given some of the recent advances in ICN protocol development and that the resulting suite is simpler and potentially having better performance and robustness properties. Our sketch of an ICN based protocol framework addresses secure and efficient establishment and continuation of REST communication sessions, without giving up key ICN properties, such as consumer anonymity and flow balance.

Representational State Transfer in the Web Today

The Web today is based on an extended version of the Representational State Transfer (REST) architecture pattern for client-server interaction. This simple model has been extended and applied to HTTP for web applications by supporting not only retrieval, but also creation, processing, and deletion of data. Real-world REST systems employ additional concepts and mechanisms such as security and privacy, support for application sessions, and have various optimizations to eliminate unnecessary round-trips.

REST and ICN

Since nearly all web applications today are based on the RESTful client-server communication model, the question then occurs how such interactions can be achieved in ICN, i.e., secure and confidential RESTful access to web resources, with support for efficient handling of a sequence of interactions in a session-like context.

The applicability of ICN's Interest/Data interaction to modern web applications that provide a significant amount of data in requests headers for cookies and other request parameters has been assessed by Moiseenko et al., concluding that it is not immediately clear how to use ICN effectively for web communication. We have also argued in our earlier RICE paper on Remote Method Invocation in ICN that the basic Interest/Data exchange model of CCNx/NDN-style ICN is not sufficient and that certain use cases (e.g., sending resource representations or request parameters from a client to a server) should not be implemented by overloading the Interest message.

In draft-oran-icnrg-reflexive-forwarding, we have discussed the specific problems extensively. In its default mode, ICN also lacks name privacy, which we consider essential for any real-world application of ICN to web services. However, various techniques have been developed to improve name privacy in ICN, such as the onion routing approach in ANDaNA (Anonymous Named Data Networking Application).

In our vision paper on RESTful Information-Centric Networking at [ACM ICN-2022 (https://conferences2.sigcomm.org/acm-icn/2022/), we argue that an ICN-based RESTful programming model that overcomes these limitations is feasible given some of the recent advances in ICN protocol development and provide the outline of the corresponding protocol framework.

HTTP has been extended and partially redesigned over time, and provides its own idiosyncratic conventions and mechanisms, e.g., which request-relevant information to represent in the URI vs. message headers vs. message bodies. The goal of this work is not to simply map current HTTP mechanisms to ICN, but rather to provide an ICN-idiomatic platform for RESTful applications including an Information-Centric web.

Any ICN web platform will only be useful and relevant if it provides equivalent (or better) security and privacy properties as the state-of-art, i.e., HTTP3 over QUIC and TLS 1.3, so our proposed framework provides a TLS-like security context for RESTful communication (sessions). Also, RESTful ICN should not compromise on existing ICN benefits such as consumer anonymity and consumer mobility.

Our technical design integrates CCNx Key Exchange (a TLS-1.3-like key exchang protocol for ICN) and our Reflexive Forwarding scheme for ICN, and uses that for providing symmetric key derivation and efficient RESTful communication and session resumption in an ICN-idiomatic way. Please check out our paper for details.

References

• Dirk Kutscher and David Oran. 2022; RESTful information-centric networking: statement; In Proceedings of the 9th ACM Conference on Information-Centric Networking (ICN '22); Association for Computing Machinery, New York, NY, USA, 150–152. https://doi.org/10.1145/3517212.3558089
• ACM ICN-2022
• David Oran and Dirk Kutscher; Reflexive Forwarding for CCNx and NDN Protocols; Internet Draft draft-oran-icnrg-reflexive-forwarding, Work in Progress
• Marc Mosko, Ersin Uzun, Christopher A. Wood; CCNx Key Exchange Protocol Version 1.0; Internet Draft draft-wood-icnrg-ccnxkeyexchange-02, Work in Progress; January 2018

Abstract

Connecting low-power long-range wireless networks, such as LoRa, to the Internet imposes significant challenges because of the vastly longer round-trip-times (RTTs) in these constrained networks. In our newly published paper on "Delay-Tolerant ICN and Its Application to LoRa" at ACM ICN-2022, we present an Information-Centric Networking (ICN) protocol framework that enables robust and efficient delay-tolerant communication to edge networks, including but not limited to LoRa. Our approach provides ICN-idiomatic communication between networks with vastly different RTTs for different use cases. We applied this framework to LoRa, enabling end-to-end consumer-to-LoRa-producer interaction over an ICN-Internet and asynchronous ("push") data production in the LoRa edge. Instead of using LoRaWAN, we implemented an IEEE 802.15.4e DSME MAC layer on top of the LoRa PHY layer and ICN protocol mechanisms in the RIOT operating system. For our experiments, we connected constrained LoRa nodes and gateways on IoT hardware platforms to a regular, emulated ICN network and performed a series of measurements that demonstrate robustness and efficiency improvements compared to standard ICN.

Challenging Bi-Directional LoRa Communication

LoRaWAN provides a vertically integrated network architecture for connecting LoRa networks and its constrained devices to the Internet that is designed to offload power-constrained gateways relay communication between the wireless link and network servers (often co-located with additional application server infrastructure) that manage the intricate energy-conservation regime of connected LoRa devices.

The energy conservation objectives lead to a MAC layer design that incurs dramatically higher latency and round trip times (RTTs) of several seconds, compared to what connection-oriented Internet transport protocols are typically designed to support. As a result, LoRaWAN supports message-oriented transport through gateways and dedicated network servers only, without a notion of end-to-end communication from the Internet to LoRa nodes. While it is theoretically possible to run bidirectional IP-based communication on top of LoRaWAN, the resulting systems inherit latency challenges of LoRaWAN for bi-directional communication that would impact transport layer performance and applicability.

Delay-Tolerant Information-Centric Networking

Information-Centric Networking (ICN) has demonstrated benefits for improving data availability and communication performance in constrained IoT networks.

In a newly published paper on "Delay-Tolerant ICN and Its Application to LoRa" at ACM ICN-2022, Peter Kietzmann, José Alamos, Thomas Schmidt, Matthias Wählisch and myself argue that ICN is also a suitable network layer for connecting such challenged edge networks to a more regular Internet, by leveraging hop-by-hop transport functions, ICN caching and minimal application-agnostic extensions.

In earlier work, we have described a design of an improved, IEEE 802.15.4e DSME-based MAC layer for LoRa that supports packet-based communication, specifically ICN-style Interest/Data communication. Yet, RTTs can still be on the order of seconds due to the underlying power saving regime. Leveraging their work, we take an ICN-enabled LoRa subnet as a basis which is attached via an ICN forwarder on a gateway device. We developed a delay-tolerant ICN communication framework that allows connecting these LoRa sub-networks to a "regular" ICN Internet, with the following design goals:

1. supporting IoT sensor data transmission;
2. supporting arbitrary orders of delays, without specific assumptions of typical RTTs on other nodes on the ICN Internet;
3. not requiring application awareness on gateway nodes;
4. utilizing ICN-idiomatic communication to benefit from ICN principles such as accessing named data, Interest/Data semantics, caches, flow balance, etc.

We have developed interactions for IoT communication use cases that leverage bespoke (but application-agnostic) capabilities on gateway-based forwarders and the Reflexive Forwarding extensions for ICN that Dave Oran and I developed for Remote Method Invocation, RESTful communication, and IoT push data scenarios.

Our LoRa systems features two interaction patterns. First, IoT sensor data retrieval from an Internet-based consumer using Interest/Data interactions; and second, asynchronously "pushing'' data from an IoT sensor to an Internet-based consumer with pub/sub semantics.

Results

The contributions of out work are the following:

1. The design of delay-tolerant ICN-interactions and node behavior for this constrained environment.
2. A complete implementation of the DSME MAC layer for LoRa and our ICN protocol extensions on RIOT, serving common LoRa sensors and RIOT-based gateways.
3. An experiment-based evaluation of the interactions on constrained IoT hardware, connected to an emulated ICN-Internet, and a comparison with vanilla ICN approaches.

In conjunction with the OS-level implementation of ICN (and extensions), DSME, and LoRa, our two protocol mechanisms for Internet consumer-initiated and LoRa producer-initiated communication exhibit high reliability and targeted completion time (compared to Vanilla ICN) when applied to the delay-prone regime.

Despite an additional round trip, our evaluations in the paper exhibit low overhead of these approaches by overcoming redundant polling. We leveraged recently proposed gateway behavior (such as RICE) and ICN protocol extensions (reflexive forwarding), the latter of which serves many other use cases beyond phoning home and could be considered a useful standard ICN feature.

References

• ACM ICN-2022 Conference
• Pre-print of our paper
• Presentation video
• Previous work on the DSME and ICN network design
• Reflexing Forwarding Framework
• RIOT Operating System

LoRaWAN is a popular low-power long-range communication system for IoT that is suitable for single-site deployments as well as for larger networks. It consists of LoRa, a PHY layer that allows for radio communication between 2 and 14 km, and higher-layer protocols mainly to upload IoT data to a serverbased infrastructure. These characteristics make LoRaWAN a promising option for many urban and rural IoT scenarios.

The LoRaWAN network design incurs, however, four notable shortcomings:

1. LoRaWAN is heavily optimized towards retrieving data from constrained Nodes. Sending data to Nodes is expensive and involves significant latencies. Many networks such as the popular community The Things Network (TTN) thus deprecate sending data to Nodes above a very low message rate, making LoRaWAN unsuitable for most control scenarios.
2. LoRaWAN has not been designed with the objective to provide a platform for Internet protocols. It is possible to use IP and adaptation layers on top of LoRaWAN, albeit very inefficiently.
3. The whole LoRaWAN system is a vertically integrated stack that leads to inflexible system designs and inefficiencies. For example, all communication is channeled through LoRaWAN Gateways as well as Application- and Network Servers that interconnect with applications.
4. The centralization and lock-in into vertical protocol stacks challenge data sharing (between users) and the creation of distributed applications (across LoRa island and the Internet).

A new LoraWAN architecture based on DSME and ICN

In our IFIP Networking 2022 paper "Long-Range ICN for the IoT: Exploring a LoRa System Design", Peter Kietzmann, José Alamos, Thomas C. Schmidt, Matthias Wählisch, and myself aim for a better integration of the LoRa-based Internet of Things into the remaining Internet. We base our system design on the following four requirements:

1. enabling LoRa networks and Nodes in these networks to communicate directly with hosts on the Internet;
2. empowering LoRa Gateways to act as routers, without the need to employ Network Servers and to tunnel all traffic to or from them;
3. enabling secure data sharing and wireless Node control; and
4. maintaining the important power conservation and robustness properties of current LoRaWAN systems.

To achieve these goals without abandoning the benefits of the LoRA PHY (i.e., a robust, energy-efficient long-range communication channel) we developed both a complete redesign of the MAC layer and a data-oriented network layer on top. Our work leverages two key building blocks.

1. the Deterministic and Synchronous Multi-Channel Extension (DSME) extension to IEEE 802.15.4e, a flexible MAC layer that consists of contention-access and contention-free periods, and,
2. the Information-Centric Networking (ICN) protocol NDN, which provides secure access to named data in networks.

LoRa and ICN

Prior work showed that ICN provides clear benefits over traditional IP and CoAP or MQTT stacks in the IoT. Our research showed that ICN is also well-suited for LoRa networks because its hop-wise data replication increases robustness and flexibility while reducing retransmission load. This enhances adaptivity and decreases communication overhead, whereas link capacity is scarce with LoRa. Named and authenticated data access enables location-independence since applications can access named data directly, without resorting to lower-layer addresses. Furthermore, built-in caches in ICN facilitate more efficient LoRa networks. Requests that are satisfied by an in-network cache

1. reduce link utilization, to improve on air time and wireless interference;
2. facilitate Node sleep; and
3. reduce long round trips introduced by slow transmissions.

Results

In our paper, we describe

1. the design of ICN over LoRa, including a suitable DSME configuration and options for mapping ICN messages to DSME;
2. a complete simulation environment in OMNeT++ that combines ccnSim as an ICN stack, openDSME as a MAC layer, and FLoRa to simulate LoRa-type devices—and a demonstration of our adaptation layers in that system.
3. Preferred mappings and additional Node requirements for implementing relevant ICN interaction patterns, based on our simulation results.

Code and documentation is available at https://github.com/inetrg/IFIP-Networking-LoRa-ICN-2022, and the whole system is currently being implemented for the RIOT Operating System.

References

• Peter Kietzmann, Dirk Kutscher, Thomas C. Schmidt, Matthias Wählisch;
  Long-Range IoT: Is LoRaWAN an option for ICN?; Proceedings of the 7th ACM Conference on Information-Centric Networking; September 2020; Pages 152–154; DOI10.1145/3405656.3420228
• Peter Kietzmann, José Alamos, Dirk Kutscher, Thomas C. Schmidt, Matthias Wählisch
  Long-Range ICN for the IoT: Exploring a LoRa System Design; IFIP Networking 2022; Catania, Italy; June 2022

I was on The Hedge Podcast with Russ White and Alvaro Retana to discuss Information-Centric Networking and the future of the Internet.

Ubiquitous virtual reality environments such as Metaverse have been described as the future mobile Internet, alluding to their expected profound impact on the way how information is retrieved, processed, rendered, and consumed. While detailed designs are still emerging, early visions such Keeichi Matsuda’s Hyper-Reality project have already outlined usage models and expectations on connectivity and data availability to enable rich interactions with the physical world and blending it with dynamically computed artefacts.

Metaverse systems will challenge traditional client-server-inspired web models, centralized security trust anchors and server-style distributed computing. The new network will be based on dynamic interactions between humans, the phyiscal world, and computing processes in an edge-to-cloud continuum. This talk will outline the associated challenges, review recent work in distributed computing and suggest some approaches for evolving networking and computing to enable Metaverse – not as a dystopian vision but as an opportunity for societies and their citizens.

Download presentation

The Dataflow paradigm is a popular distributed computing abstraction that is leveraged by several popular data processing frameworks such as Apache Flink and Google Dataflow. Fundamentally, Dataflow is based on the concept of asynchronous messaging between computing nodes, where data controls program execution, i.e., computations are triggered by incoming data and associated conditions. This typically leads to very modular system architectures that enable re-use, re-composition, and parallel execution naturally. Most of the popular distributed processing frameworks today are implemented as overlays, i.e., they allow for instantiating computations and for inter-connecting them, for example by creating and maintaining communication channels between nodes such as system processes and microservices.

Connections and Overlays

The connection-based approach incurs several architectural problems and inefficiencies, for example: application logic is concerned with receiving and producing data as a result of computation processes but connections imply transport endpoint addresses that are typically not congruent. This typically implies a mapping or orchestration system. One key goal for Dataflow systems is to enable parallel execution, i.e., one computation is run in parallel, which also affects the communication relationships with upstream producers and downstream consumers. For example, when parallelizing a computation step, it typically implies that each instance is consuming a partition of the inputs instead of all the inputs. An indirection- and connection-based approach makes it harder to configure (and especially to dynamically re-configure) such dataflow graphs.

In some variants of Dataflow, for example stream processing, it can be attractive if one computation output can be consumed by multiple downstream functions. Connection-based overlays typically require duplicating the data for each such connection, incurring significant overheads. In large-scale scenarios, the computation functions may be distributed to multiple hosts that are inter-connected in a network. Orchestrators may have visibility into compute resource availability but typically have to treat the TCP/IP network as a blackbox. As a result, the actual data flow is locked into a set of overlay connections that do not necessarily follow optimal paths, i.e., the communication flows are incongruent with the logical data flows.

IceFlow: Information-Centric Dataflow

In our ACM ICN 2021 paper Vision: Information-Centric Dataflow – Re-Imagining Reactive Distributed Computing, we present IceFlow – an Information-Centric Dataflow system approach that supports traditional Dataflow with Information-Centric principles and that can be used as a drop-in replacement for existing Dataflow-based frameworks.

In addition to the paper, we also show a live of a joint optimization of computing and networking resources in IceFlow: Decentralized ICN-based dataflow system implementation.

IceFlow’s objectives are:

1. reducing complexity in Dataflow systems by removing connection-based overlays and corresponding orchestration requirements;
2. enabling efficient communication by reducing data duplication; and
3. enabling additional improvements through more direct communication and caching in the network.

IceFlow is employing access to authenticated data in the network as per CCNx/NDN-based ICN for the communication between computation functions and provides additional features such as flowcontrol, partitions for data streaming, and a window concept for synchronizing computations in streaming pipelines. The contributions of this paper are:

1. an ICN naming scheme for Dataflow;
2. a concept for receiver-driven flow control in IceFlow-based Dataflow systems and for dealing with parallel processing in IceFlowbased Dataflow systems; and
3. a prototype implementation.

Links

• ACM ICN 2021
• Vision: Information-Centric Dataflow – Re-Imagining Reactive Distributed Computing
• Decentralized ICN-based dataflow system implementation

In der neuen Folge unseres Podcasts Neulich im Netz widmen wir uns eines etwas delikateren Themas: Zensur im Internet

Insbesondere geht es um die "Great Firewall of China" (GFW), die wir in Bezug auf ihre technische Umsetzung und Probleme analysiert haben.

Anhand von Publikationen und eigenen Erfahrungen analyisieren wir, wie die GFW grob funtioniert, kontinuiierlich weiterentwickelt wird, und wie effektiv unterschiedliche Werkzeuge wie VPNs, shadowsocks usw. sind.

Diese und weitere Aspekte von Zensur im Internet in der dritten Episode von Neulich im Netz.

In der neuen Folge unseres Podcasts Neulich im Netz geht um Namen im Internet, d.h., um das Domain Name System (DNS). Wir sprechen über grundlegende DNS-Funktionen, die Bedeutung, die das DNS für das Internet und das Web hat und über Anwendungen wie Tracking und Traffic Steering, die man vielleicht nicht unbedingt mit Namensauflösung in Verbindung bringt.

Wir diskutieren, inwieweit das technische Design des DNS und seine heutige Verwendung zu Sicherheitsproblemen führt und beurteilen einige vorgeschlagene Verbesserungen. Ist das DNS in der heutigen Form noch zu retten? Wie stehen die Chancen dafür? Diese und andere Frage in der zweiten Episode von Neulich im Netz.

Low-power, long-range radio systems such as LoRaWAN represent one of the few remaining networked system domains that still feature a complete vertical stack with special link- and network layer designs independent of IP. Similar to local IoT systems for low-power networks (LoWPANs), the main service of these systems is to make data available at minimal energy consumption, but over longer distances. LoRaWAN (the system that comprises the LoRa PHY and MAC) supports bi-directional communication, if the IoT device has the energy budget. Application developers interface with the system using a centralized server that terminates the LoRaWAN protocol and makes data available on the Internet.

While LoRaWAN applications are typically providing access to named data, the existing LoRaWAN stack does not support this way of communicating. LoRaWAN is device-centric and is generally designed as a device-to-server messaging system – with centralized servers that serve as rendezvous point for accessing sensor data. The current design imposes rigid constraints and does not facilitate accessing named data natively, which results in many point solutions and dependencies on central server instances.

In our demo paper & presentation at ACM ICN-2020, we are therefore describing how Information-Centric Networking could provide a more natural communication style for LoRa applications and how ICN could help to conceive LoRa networks in a more distributed fashion compared to todays mainstream LoRaWAN deployments. For LoWPANs (e.g., 802.15.4 networks), ICN has already demonstrated to be an attractive and viable alternative to legacy integrated special purpose stacks – we believe that
LoRa communication provides similar opportunities.

Watch my Peter Kietzmann's talk about it here:

Edge- and, more generally, in-network computing is receiving a lot attention in research and industry fora. What are the interesting research questions from a networking perspective? In-network computing can be conceived in many different ways - from active networking, data plane programmability, running virtualized functions, service chaining, to distributed computing. Modern distributed computing frameworks and domain-specific languages provide a convenient and robust way to structure large distributed applications and deploy them on either data center or edge computing environments. The current systems suffer however from the need for a complex underlay of services to allow them to run effectively on existing Internet protocols. These services include centralized schedulers, DNS-based name translation, stateful load balancers, and heavy-weight transport protocols.

Over the past years, we have been working on alternative approaches, trying to find ways for integrating networking and computing in new ways, so that distributed computing can leverage networking capabilities directly and optimize usage of networking and computing resources in a holistic fashion.

From Application-Layer Overlays to In-Network Computing

Domain-specific distributed computing languages like LASP have gained popularity for their ability to simply express complex distributed applications like replicated key-value stores and consensus algorithms. Associated with these languages are execution frameworks like Sapphire and Ray that deal with implementation and deployment issues such as execution scheduling, layering on the network protocol stack, and auto-scaling to match changing workloads. These systems, while elegant and generally exhibiting high performance, are hampered by the daunting complexity hidden in the underlay of services that allow them to run effectively on existing Internet protocols. These services include centralized schedulers, DNS-based name translation, stateful load balancers, and heavy-weight transport protocols.

We claim that, especially for compute functions in the network, it is beneficial to design distributed computing systems in a way that allows for a joint optimization of computing and networking resources by aiming for a tighter integration of computing and networking. For example, leveraging knowledge about data location, available network paths and dynamic network performance can improve system performance and resilience significantly, especially in the presence of dynamic, unpredictable workload changes.

The above goals, we believe, can be met through an alternative approach to network and transport protocols: adopting Information-Centric Networking as the paradigm. ICN, conceived as a networking architecture based on the principle of accessing named data, and specific systems such as NDN and CCNx have accommodated distributed computation through the addition of support for remote function invocation, for example in Named Function Networking, NFN and RICE, Remote Method Invocation in ICN and distributed data set synchronization schemes such as PSync.

Introducing Compute First Networking (CFN)

We propose CFN, a distributed computing environment that provides a general-purpose programming platform with support for both stateless functions and stateful actors. CFN can lay out compute graphs over the available computing platforms in a network to perform flexible load management and performance optimizations, taking into account function/actor location and data location, as well as platform load and network performance.

We have published a paper about CFN at the ACM ICN-2019 Conference that is being presented in Macau today by Michał Król. The paper makes the following contributions:

1. CFN marries a state-of-the art distributed computing framework to an ICN underlay through RICE, Remote Method Invocation in ICN. This allows the framework to exploit important properties of ICN such as name-based routing and immutable objects with strong security properties.
2. We adopted the rigorous computation graph approach to representing distributed computations, which allows all inputs, state, and outputs (including intermediate results) to be directly visible as named objects. This enables flexible and fine-grained scheduling of computations, caching of results, and tracking state evolution of the computation for logging and debugging.
3. CFN maintains the computation graph using Conflict-free Replicated Data Types (CRDTs) and realizes them as named ICN objects. This enables implementation of an efficient and failure-resilient fully- distributed scheduler.
4. Through evaluations using ndnSIM simulations, we demonstrate that CFN is applicable to range of different distributed computing scenarios and network topologies.

Resources and Links

• My keynote at IEEE CCNC-2019 on Compute-First Networking (CFN): New Perspectives on Integrating Computing and Networking
• Internet Draft draft-kutscher-coinrg-dir-00 with Jörg Ott and Teemu Kaerkkaeinen on Directions for Computing in the Network (COIN) and the corresponding presentation.
• The CFN paper at ACM ICN-2019: Compute First Networking: Distributed Computing meets ICN. The author team: Michał Król, Spyridon Mastorakis, David Oran, Dirk Kutscher
• CFN builds on our earlier work on RICE, Remote Method Invocation in ICN, authored by: Michał Król, Karim Habak, Karim Habak, Dirk Kutscher, Ioannis Psaras
• 1st ACM CoNEXT Workshop on Emerging in-Network Computing Paradigms (ENCP)
• IRTF Computing in the Network Proposed Research Group (COIRG)