Dirk Kutscher

The Information-Centric Networking Research Group (ICNRG) of the Internet Research Task Force (IRTF) met at IETF-119 in Brisbane. Here is my quick summary of the meeting:

Agenda:

Meeting material:

• All presentation material
• Meeting minutes
• Meeting video

ICNRG Status

ICNRG recently published four news RFCs – great achievement by all involved authors and the whole group!

• RFC 9510: Alternative Delta Time Encoding for Content-Centric Networking (CCNx) Using Compact Floating-Point Arithmetic
• RFC 9531: Path Steering in Content-Centric Networking (CCNx) and Named Data Networking (NDN)
• RFC 9508: Information-Centric Networking (ICN) Ping Protocol Specification
• RFC 9507: Information-Centric Networking (ICN) Traceroute Protocol Specification

See my blog posting for a more detailed description.

Secure Web Objects and Transactions

One focus of this meeting was transactions in ICN, i.e., interactions with the intention to achieve some durable state change at a remote peer – which imposes some challenges in a system that is designed around accessing named data.

In my presentation I talked about different ways to realize transactions in ICN:

1. ICN as a network layer
   • Client-server communication between two nodes
   • Implement transaction semantics on top of an ICN messaging service
2. Recording state changes in shared data structures
   • Shared namespace, potentially functioning as a transaction ledger
   • Still need to think about atomicity etc

For 1) transactions as messaging over ICN networks, the following considerations apply:

• Client-server communication between two nodes
• Implement transaction semantics on top of an ICN messaging service
• Different approaches
  • A: Traditional layering: Using NDN-like systems as a messaging layer
  • Assign prefixes to client & servers
  • Send messages back and forth, and implement reliability and transactions semantics on top
  • B: ICN-native communication: Use Interest-Data as request-response abstraction for transactions
  • Mapping transaction communication and state evolution more directly to ICN, e.g., Interest-Data in NDN
  • Collapsing traditional network, transport, application layer functions

I mainly talked about variant 1B, ICN-native communication: Use InterestData as request-response abstraction for transactions and introduced the idea of "Secure Web Objects" (SWOs) for a data-oriened web as a motivation.

In such a system, not everything would be about accessing named data object – there is also a need for "client/server" state evolution, e.g., for online banking and similar use cases.

I introduced some ideas on RESTful ICN that we published in an earlier paper. The Restful ICN proposal leverages Reflexive Forwarding, for robust client-server communication and integrates elements of CCNx key exchange for security context setup and session resumption.

Summarizing, I wanted to initiate a discussion about how to realize transactions in information-centric systems? This discussion is not about mapping ICN to existing protocols, such as HTTP, but about actual distributed computing semantics, i.e., robust session setup and state evolution. Transactions with ICN-native communication are hard to provide with with basic Interest/Data. Reflexive Forwarding + CCNx Key Exchange + transaction semantics are an attempt to provide such a service in a mostly ICN-idiomatic way, with the downside that reflexive forwarding needs extensions to forwarders. This raises question on the minimal feature set of core ICN protocols, and to deal with extensions.

In the discussion, it was pointed out that lots of experience on distributed systems has shown that transactions or secure multi-interactions will generally require more than a single two-way exchange.

Others suggested that ICN and NDN has authentication carried out when the signed interest arrives which directly proves authentication, so that the authentication would in fact be done beforehand.

However, authentication may not be enough. For example, client authorization in client-server communication is a critical function which needs to be carefully designed in real-world networks. For example, forcing a server to do signature verification on initial request arrival has been shown in prior systems (e.g. TCP+TLS) to represent a serious computational DOS attack risk. Reflexive Forwarding in RICE tries to avoid exactly that problem, by enabling the server to iteratively authenticate and authorize clients before committing computing resources.

It was also said that whenever a protocol does authentication. you need to analyze in the context of specific examples to discuss, and that cannot only look at the problem at an abstract level.

Transaction Manifests

Marc Mosko presented another approach to transactions in ICN, called [Transaction Manifests](https://datatracker.ietf.org/meeting/119/materials/slides-119-icnrg-transaction-manifests-00 "Transaction Manifests "Transaction Manifests"). He explained that ICN can be transactional.

Typically, ICN is considered as a publish/subscribe or pre-publishing of named-data approach. Outside ICN, distributed transactions do exist, especially in DLTs. For example, considering a permissioned DLT with size N and K << N bookkeepers. In a DLT, they base their decision on the block hash history. In this talk, Marc discussed what would be an equivalent function in ICN, and introduced the notion of transaction manifests.

In ICN, there is a technology called FLIC (File-like collections), i.e., manifests for static objects. FLIC describes a single object that is re-constructed by traversing the manifest in order. In Marc's proposal, a transaction manifest describes a set of names that must be considered together. The transaction manifest names likely point to FLIC root manifests.

In the example above, transaction manifest entries entries point directly to objects. For a complete systems, you would also need a set of bookkeepers, e.g., systems like Hyperledger offering global ordering vis bespoke orderer nodes. Such bookkeeper would have to ensure that a transaction has current pre-conditions, current post-conditions, and no conflicts in post-conditions. Transaction manifests are a form of write-ahead logs (WAL), as used in databases, such as PostgreSQL.

Marc went on discussing a few challenges, such as interactions with repositories and caches, as well as distributed transaction manifests.

There was some discussion on the required ordering properties for this approach, i.e., whether, in a multi-bookkeeper system, livelocks and deadlocks could occur – and whether these could resolved without requiring a total order.

Marc is continueing to work on this. One of the next steps would be to design client-to-bookkepper and bookkeeper-to-bookkeeper protocols.

Vanadium: Secure, Distributed Applications

Marc Mosko introduced the Vanadium system, a secure, distributed RPC system based on distributed naming and discovery. Vanadium uses symmetrical authentication and encryption and may use private name discovery with Identity-Based-Encryption (IBE).

Vanadium has two parts:

1. Principals and Blessings and Caveats (Security)
   • Use a hierarchical name, e.g. alice:home:tv.
   • Certificate based
   • Blessings are scoped delegations from one principal to another for a namespace (e.g. alice grants Bob “watch” permissions to the TV)
   • Caveats are restrictions on delegations (e.g. Bob can only watch 6pm – 9pm).
   • 3rd party caveats must be discharged before authorization
   • E.g. revocations or auditing
2. The RPC mount tables (Object Naming)
   • These describe how to locate RPC namespaces
   • They provide relative naming

Vanadium is interesting because parts of its design resemble some ICN concepts, especially the security part:

• It uses prefix matching and encryption
• Namespaces work like groups
• The colon : separates the blesser from the blessed
• Authorizations match extensions.
  • If Alice authorized “read” to alice:hometv to alice:houseguests, and if Bob has a blessing for alice:houseguests:bob, then Bob has “read” to alice:hometv.
• A special terminator :$ only matches the exact prefix.
  • A blessing to alice:houseguest:$ only matches that exact prefix.

Marc then explain the object naming structure and the entity resolution in Vanadium.

More details can be found in Marc's presentation and on Vanadium's web page.

In summary, Vanadium is a permissioned RPC service. A Vanadium name encodes the endpoint plus name suffix. The endpoint does not need to resolve to a single mount table server, it could be any server that possesses an appropriate blessing. Authentication is done via pair-wise key exchange and blessing validations. It can be private if using IBE, otherwise server name leaks. Authorizations and Blessings and Caveats use hierarchical, prefixmatching names.

From an ICN perspective, the security approach seems interesting. Blessings and Caveats and discharges and namespaces as groups. One question is how this differs from SDSI co-signings. The Vanadium identity service provides an interesting mapping of OAuth2 app:email tokens to PKI and blessings. The RPC approach exhibits some differences to ICN, e.g., embedding the endpoint identifier in the name. ICN technologies in this context are public-key scoped names in CCNx and schematized trust anchors in NDN.

In the discusion, it was noted that it would be interesting to do an apples-to-apples comparison to the NDN trust schema approach; Vanadium's approach with the ability to create blessings and caveats on demand seems to be much more granular and dynamic.

Global vs. Scoped Namespaces

Marc Mosko discussed global vs. scoped namespaces. For example, how do you know that the key you are looking at is the key that you should be looking at? IPFS punts that to out-of-band mechanisms. CCNX on the other hand uses public key scoped names; you can put a public key, publisher ID in an interest and say you only wanyt this name if signed with the associated key.

It was suggested to re-visit some of the concepts in the RPC system of OSF distributed computing, where all namespaces were scoped, and name discovery starts out as local. You could then "attach" a local namespace to more global namespace via an explicit "graft" operation. The key here was that the authoritative pointers representing the namespace graph were from child to parent, as opposed to parent to child as it is with systems like DNS. Your local trust root identifier could become a name in a higher layer space, yielding a trust root higher in the hierarchy tha could be used instead of or in addition to your local trust root. Doing this can create progressively more global name spaces out of local ones.

Please check out the meeting video for the complete discussion at the meeting.

In the Information-Centric Networking Research Group (ICNRG) of the Internet Research Task Force (IRTF) we have recently published a set of new RFCs:

RFC 9510: Alternative Delta Time Encoding for Content-Centric Networking (CCNx) Using Compact Floating-Point Arithmetic

Content-Centric Networking (CCNx) utilizes delta time for a number of functions. When using CCNx in environments with constrained nodes or bandwidth-constrained networks, it is valuable to have a compressed representation of delta time. In order to do so, either accuracy or dynamic range has to be sacrificed. Since the current uses of delta time do not require both simultaneously, one can consider a logarithmic encoding. This document updates RFC 8609 ( to specify this alternative encoding.

RFC 9531: Path Steering in Content-Centric Networking (CCNx) and Named Data Networking (NDN)

Path steering is a mechanism to discover paths to the producers of Information-Centric Networking (ICN) Content Objects and steer subsequent Interest messages along a previously discovered path. It has various uses, including the operation of state-of-the-art multi-path congestion control algorithms and for network measurement and management. This specification derives directly from the design published in https://dl.acm.org/doi/10.1145/3125719.3125721 (4th ACM Conference on Information-Centric Networking) and, therefore, does not recapitulate the design motivations, implementation details, or evaluation of the scheme. However, some technical details are different, and where there are differences, the design documented here is to be considered definitive.

RFC 9508: Information-Centric Networking (ICN) Ping Protocol Specification

This document presents the design of an Information-Centric Networking (ICN) Ping protocol. It includes the operations of both the client and the forwarder.

Ascertaining data plane reachability to a destination and taking coarse performance measurements of Round-Trip Time (RTT) are fundamental facilities for network administration and troubleshooting. In IP, where routing and forwarding are based on IP addresses, ICMP Echo Request and ICMP Echo Reply packets are the protocol mechanisms used for this purpose, generally exercised through the familiar ping utility. In Information-Centric Networking (ICN), where routing and forwarding are based on name prefixes, the ability to ascertain the reachability of names is required.

In order to carry out meaningful experimentation and deployment of ICN protocols, new tools analogous to ping and traceroute used for TCP/IP are needed to manage and debug the operation of ICN architectures and protocols. This document describes the design of a management and debugging protocol analogous to the ping protocol of TCP/IP; this new management and debugging protocol will aid the experimental deployment of ICN protocols. As the community continues its experimentation with ICN architectures and protocols, the design of ICN Ping might change accordingly. ICN Ping is designed as a "first line of defense" tool to troubleshoot ICN architectures and protocols. As such, this document is classified as an Experimental RFC. Note that a measurement application is needed to make proper use of ICN Ping in order to compute various statistics, such as average, maximum, and minimum Round-Trip Time (RTT) values, variance in RTTs, and loss rates.

RFC 9507: Information-Centric Networking (ICN) Traceroute Protocol Specification

This document presents the design of an Information-Centric Networking (ICN) Traceroute protocol. This includes the operation of both the client and the forwarder.

In TCP/IP, routing and forwarding are based on IP addresses. To ascertain the route to an IP address and to measure the transit delays, the traceroute utility is commonly used. In Information-Centric Networking (ICN), routing and forwarding are based on name prefixes. To this end, the ability to ascertain the characteristics of at least one of the available routes to a name prefix is a fundamental requirement for instrumentation and network management. These characteristics include, among others, route properties such as which forwarders were transited and the delay incurred through forwarding.

In order to carry out meaningful experimentation and deployment of ICN protocols, new tools analogous to ping and traceroute used for TCP/IP are needed to manage and debug the operation of ICN architectures and protocols. This document describes the design of a management and debugging protocol analogous to the traceroute protocol of TCP/IP; this new management and debugging protocol will aid the experimental deployment of ICN protocols. As the community continues its experimentation with ICN architectures and protocols, the design of ICN Traceroute might change accordingly. ICN Traceroute is designed as a tool to troubleshoot ICN architectures and protocols.

Research and development in ICN has led to different communication patterns such as Sync and API implementations such as CNL. It is now time to think about how to leverage Information-Centric principles for providing better foundations for hypermedia applications in the future web. At NDNComm-2024 I talked about how ICN could possibly help, what could be fruitful future research directions, and why web3 and dweb are not the answer.

Material

Presentation

The emerging term In-Network Computin (INC) [inc] in particular refers applying on-path programmable networking devices (e.g., switches and routers between clients and servers) as an accelerator or function offloader to boost throughput, reduce server load, or improve latency, typically in a well-controlled data center network environment.

Some INC implementations evolved from programmable data plane systems and align with the trend of network programmability at large. In recent year, it has been shown to support many promising applications (e.g., caching, aggregation, and agreement). For example, in distributed machine learning (DML), training nodes produce data (gradients) that needs to be aggregated or reduced -- and the result could be distributed to one or multiple consumers. As another example, the NetClone system [netclone] uses in-network forwarder to replicate RPC invocation messages and to perform more informed forwarding based on observed latencies for accelerating RPC communication.

While it is possible to achieve this kind of operation purely with end-to-end communication between worker nodes, performance can be dramatically improved by offloading both the operation processing and the data dissemination to nodes in the network. These in-network processors are often conceived as semi-transparent performance enhancing on-path elements, i.e., they are not the actual endpoints in transport protocol sessions and would intercept packets with application data and potentially generate new data that they would have to transmit.

In our Internet Draft draft-song-inc-transport-protocol-req-01.txt, we are discussing this problem and are formulating some requirements for the design of future transport protocols in this space.

References

• Collective Communication: Better Network Abstractions for AI
• Computing in the Network – Lessons Learned and New Opportunities
• [I-D.yao-tsvwg-cco-problem-statement-and-usecases] Yao, K., Shiping, X., Li, Y., Huang, H., and D. KUTSCHER, "Collective Communication Optimization: Problem Statement and Use cases", Work in Progress, Internet-Draft, draft-yao-tsvwg-cco-problem-statement-and-usecases-00, 23 October 2023, https://datatracker.ietf.org/doc/html/draft-yao-tsvwg-cco-problem-statement-and-usecases-00.
• [inc] Klenk et al., B., "An In-Network Architecture for Accelerating Shared-Memory Multiprocessor Collectives", ACM/IEEE 47th Annual International Symposium on Computer Architecture (ISCA), 2020, <https:dx.doi.org/10.1109/ISCA45697.2020.00085>
• [netclone] Kim, G., "NetClone: Fast, Scalable, and Dynamic Request Cloning for Microsecond-Scale RPCs", In Proceedings of the ACM SIGCOMM 2023 Conference (ACM SIGCOMM '23). Association for Computing Machinery, New York, NY, USA, 195-207, 2023 https://dl.acm.org/doi/10.1145/3603269.3604820

We published a paper on automated remote bootstrapping in Named Data Networking (NDN):

Tianyuan Yu, Xinyu Ma, Hongcheng Xie, Dirk Kutscher, Lixia Zhang; Cornerstone: Automating Remote NDN Entity Bootstrapping; Asian Internet Engineering Conference (AINTEC) 2023; December 2023; doi/10.1145/3630590.3630598

Abstract

To secure all communications, Named Data Networking (NDN) requires that each entity joining an NDN network go through a bootstrapping process first, to obtain its initial security credentials. Several solutions have been developed to bootstrap IoT devices in localized environments, where the devices being bootstrapped are within the physical reach of their bootstrapper. However, distributed applications need to bootstrap remote users and devices into an NDN-based system over insecure Internet connectivity. In this work, we take Hydra, a federated distributed file storage system made of servers contributed by multiple participating organizations, as a use case to drive the design and development of a remote bootstrapping solution, dubbed Cornerstone. We describe the design of Cornerstone, evaluate its effectiveness, and discuss the lessons learned from this process.

We just published our IEEE Communications Magazine article on Rethinking LoRa for the IoT with an Open Access license.

LoraWAN and the Internet

Internet of Things (IoT) interconnects numerous sensors and actuators either locally or across the global Internet. From an application perspective, IoT systems are inherently data-oriented, their purpose is often to provide access to named sensor data and control interfaces. From a device and communication perspective, things in the IoT are resource-constrained devices that are commonly powered by a small battery and communicate wirelessly.

LoRaWAN systems today integrate the LoRa physical layer with the LoRaWAN MAC layer and corresponding infrastructure support. Among the IoT radio technologies, LoRa is a versatile and popular candidate since it provides a physical layer that allows for data transmission over multiple kilometers with minimal energy consumption. At the same time, the high LoRa receiver sensitivity enables packet reception in noisy environments, which makes it attractive for industrial deployments. On the downside, LoRa achieves only low data rates requiring long on-air times, and significantly higher latencies compared to radios that are typically used for Internet access.

LoraWAN MAC Layer

The LoRaWAN MAC layer and network architecture that is often used in LoRa deployments, thus provide a vertically integrated sensor data delivery service on top of the LoRa PHY that implements media access and end-to-end network connectivity. Unfortunately, LoRaWAN cannot utilize the LoRa PHY to its best potential with respect to throughput and robustness and is mostly used for upstream-only communication. It is not intended to directly interconnect with the Internet, but relies on a bespoke middlebox architecture consisting of gateways and network servers. Overall LoRaWAN has the following main problems, as depicted in the figure below.

1. Centralization around a network server prevents data sharing between users, across distributed applications, and requires permanent infrastructure backhaul of the wireless access network.
2. Uplink-oriented and uncoordinated communication leads to wireless interference. Downlink traffic is rarely available in practice and suffers from scalability issues.

Data-centric Delay-tolerant End-to-End Communication over the Internet

This paper presents an overview about recent advancements to enable data-centric, long-range IoT communication based on LoRa. The proposed network system aims for delay-tolerant, bi-directional communication in the presence of vastly longer latencies and lower bandwidth compared to regular Internet systems – without relying on vertically integrated middlebox-based architectures. The resulting system resolves current LoRaWAN performance issues using two main building blocks: a new network layer based on Information-centric Networking (ICN) and a new MAC layer.

Originally designed for non-constrained wired networks to abandon the end-to-end paradigm and access data only by names instead of IP endpoints, ICN migrated to the constrained wireless IoT over the past years. ICN still lacks a lower layer definition but provides mechanisms that are beneficial for the challenging LoRa domain: Decoupling of content from endpoints separates data access from physical infrastructure. Inherent content caching and replication potentially reduce link load, thus, wireless interference, and it preserves battery resources. The ICN-LoRa system presented in this paper bases its design on IEEE 802.15.4 DSME which was originally designed for low-power personal area networks. This MAC handles media access reliably using time- and frequency multiplexing, and enables reliable bi-directional communication.

Synergizing the advantages of LoRa, DSME, and ICN enables delay-tolerant, bi-directional LoRa communication, wich enhances many existing IoT applications. Wide area data retrieval and control as for solar power stations or smart street lighting systems are facilitated by the new MAC and its ICN integration. High voltage overhead line monitoring connecting voltage sensors and transformers relies on high data reliability, even under intermittent connectivity or loss. ICN achieves this, employing content caching and replication. Traveling container monitoring (RFC 7744) is challenging due to mobility and interference from metallic surfaces, where LoRa surpasses other radio systems. Decoupling content from its location for mobile containers and an adaptation to long producer delays are naturally contributed by LoRa-ICN.

Results

In our paper, we provide the essential technical background and challenges to design a LoRa-ICN system. We identify the key performance potentials of five protocol variants based on an implementation in RIOT OS and experiments on off-the-shelf IoT devices.

LoRa is an attractive radio technology for the IoT, providing a long wireless transmission range for battery-driven devices. Its versatility is hindered, though, by common deployments with LoRaWAN. We re-visited LoRa in the IoT to provide a serverless, data-oriented communication service. We presented the design of a new media access and network layer that leverages 802.15.4 DSME and Information-centric Networking to allow for reliable LoRa transmissions. To scale to a global Internet (of Things), LoRa-ICN facilitates ubiquitous connectivity of constrained nodes and robust bi-directional communication in the presence of power-saving regimes and high loss rates.

We showed that vastly higher latencies in low-power wireless domains can be addressed by extending the default ICN node behavior at the network edge. Two protocol extensions enable ICN-style data transport between resource-constrained LoRa nodes and a domain-agnostic application on the ICN Internet. The core idea is not limited to LoRa but caters to various delay-prone scenarios. Our experiments based on common IoT hardware and software showed significant performance improvements and further optimization potential compared to Vanilla ICN.

The new LoRa-ICN system paves the way for more versatile LoRa deployments in the IoT that serve additional use cases, mixed sensor-actor topologies, or firmware updates utilizing beacon overloading.

References

This article

• P. Kietzmann, J. Alamos, D. Kutscher, T. C. Schmidt and M. Wählisch, Rethinking LoRa for the IoT: An Information-centric Approach in IEEE Communications Magazine, doi: 10.1109/MCOM.001.2300379.

Reflexive forwarding

The ICN communication mechanisms this work is based on.

• Reflexive Forwarding in NDN
• Oran, D. R. and D. Kutscher; Reflexive Forwarding for CCNx and NDN Protocols; Work in Progress; Internet-Draft draft-oran-icnrg-reflexive-forwarding-05; 26 March 2023

In-depth publications this work is based on

• Peter Kietzmann, José Alamos, Dirk Kutscher, Thomas C. Schmidt, and Matthias Wählisch. 2022. Delay-tolerant ICN and its application to LoRa. In Proceedings of the 9th ACM Conference on Information-Centric Networking (ICN '22). Association for Computing Machinery, New York, NY, USA, 125–136. https://doi.org/10.1145/3517212.3558081
• P. Kietzmann, J. Alamos, D. Kutscher, T. C. Schmidt and M. Wählisch, Long-Range ICN for the IoT: Exploring a LoRa System Design, 2022 IFIP Networking Conference (IFIP Networking), Catania, Italy, 2022, pp. 1-9, doi: 10.23919/IFIPNetworking55013.2022.9829792. https://ieeexplore.ieee.org/document/9829792
• José Álamos, Peter Kietzmann, Thomas C. Schmidt, and Matthias Wählisch. 2022. DSME-LoRa: Seamless Long-range Communication between Arbitrary Nodes in the Constrained IoT. ACM Trans. Sen. Netw. 18, 4, Article 69 (November 2022), 43 pages. https://doi.org/10.1145/3552432

We have posted the agenda our ICNRG meeting at IETF-118:

Drafts

• https://datatracker.ietf.org/doc/draft-irtf-icnrg-flic/
• https://datatracker.ietf.org/doc/draft-yao-tsvwg-cco-problem-statement-and-usecases/00/
• https://datatracker.ietf.org/doc/draft-yao-tsvwg-cco-requirement-and-analysis/00/
• https://datatracker.ietf.org/doc/draft-li-icnrg-damc/

Logistics

ICNRG Meeting at IETF-118 – 2023-11-07, 08:30 to 10:30 UTC

• MeetEcho
• Notes
• IETF-118 Agenda

We have submitted two new Internet Drafts on Collective Communication:

1. Kehan Yao , Xu Shiping , Yizhou Li , Hongyi Huang , Dirk Kutscher; Collective Communication Optimization: Problem Statement and Use cases; Internet Draft draft-yao-tsvwg-cco-problem-statement-and-usecases-00; work in progress; October 2023

2. Kehan Yao , Xu Shiping , Yizhou Li , Hongyi Huang , Dirk Kutscher; Collective Communication Optimization: Requirement and Analysis; Internet Draft draft-yao-tsvwg-cco-requirement-and-analysis-00; work in progress; October 2023

Collective Communication refers to communication between a group of processes in distributed computing contexts, for example involving interaction types such as broadcast, reduce, all-reduce. This data-oriented communication model is employed by distributed machine learning and other data processing systems, such as stream processing. Current Internet network and transport protocols (and corresponding transport layer security) make it difficult to support these interactions in the network, e.g., for aggregating data on topologically optimal nodes for performance enhancements. These two drafts discuss use cases, problems, and initial ideas for requirements for future system and protocol design for Collective Communication. They will be discussed at IETF-118.

In a joint panel at ACM ICN-2023 and IEEE ICNP-2023 in Reykjavik, Ken Calvert, Jim Kurose, Lixia Zhang, and myself discussed future network abstractions. The panel was moderated by Dave Oran. This was one of the more interesting and interactive panel sessions I participated in, so I am providing a summary here.

Since the Internet's initial rollout ~40 years ago, not only its global connectivity has brought fundamental changes to society and daily life, but its protocol suite and implementations have also gone through many iterations of changes, with SDN, NFV, and programmability among other changes over the last decade. This panel looks into next decade of network research by asking a set of questions regarding where lies the future direction to enable continued innovations.

Opportunities and Challenges for Future Network Innovations

Lixia Zhang: Rethinking Internet Architecture Fundamentals

Lixia Zhang (UCLA), quoting Einstein, said that the formulation of the problem is often more essential than the solution and pointed at the complexities of today's protocols stacks that are apparently needed to achieve desired functionality. For example, Lixia mentioned RFC 9298 on proxying UDP in HTTP, specifically on tunneling UDP to a server acting as a UDP-specific proxy over HTTP. UDP over IP was once conceived as a minial message-oriented communication service that was intended for DNS and interactive real-time communication. Due to its push-based communication model, it can be used with minimal effort for useful but also harmful application, including large-scale DDOS attacks. Proxing UDP over HTTP addresses this and other concerns, by providing a secure channel to a server in a web context, so that the server can authorize tunnel endpoints, and so that the UDP communication is congestion controlled by the underlying transport protocol (TCP or QUIC). This specification can be seen as a work-around: sending unsolicted (and un-authenticated) messages over the Internet is a major problem in today's Internet. There is no general approach for authenticating such messages and no concept for trust in peer identities. Instead of analyzing the root cause of such problems, the Internet communities (and the dominant players in that space) prefer to come up with (highly inefficient) workarounds.

This problem was discussed more generally by Oliver Spatscheck of AT&T Labs in his 2013 article titled Layers of Success, where he discussed the (actually deployed) excessive layering in production networks, for example mobile communication networks, where regular Internet traffic is routinely tunneled over GTP/UDP/IP/MPLS:

The main issue with layering is that layers hide information from each other. We could see this as a benefit, because it reduces the complexities involved in adding more layers, thus reducing the cost of introducing more services. However, hiding information can lead to complex and dynamic layer interactions that hamper the end-to-end system’s reliability and are extremely difficult if not impossible to debug and operate. So, much of the savings achieved when introducing new services is being spent operating them reliably.

According to Lixia, the excessive layering stems from more fundamental problems with today's network architecture, notably the lack of identity and trust in the core Internet protocols and the lack of functionality in the forwarding system – leading to significant problems today as exemplied by recent DDoS attacks. Quoting Einstein again, she said that we cannot solve problems by using the same kind of thinking we used when we created them, calling for a more fundamental redesign based on information-centric networking principles.

Ken Calvert: Domain-specific Networking

Ken Calvert (University of Kentucky) provided a retrospective of networking research and looked at selected papers published at the first IEEE ICNP conference in 1993. According to Ken, the dominant theme at that time was How to design, build, and analyze protocols, for example as discussed in his 1993 ICNP paper titled Beyond layering: modularity considerations for protocol architectures.

Ken offered a set of challenges and opportunities for future networking research, such as:

• Domain-specific networking à la Ex uno pluria, a 2018 CCR editorial discussing:
  • infrastructure ossification;
  • lack of service innovation; and
  • a fragmentation into "ManyNets" that could re-create a service-infrastructure innovation cycle.
• Incentives and "money flow"
  • Can we escape from the advertising-driven Internet app ecosystem? Should we?
• Wide-area multicast (many-many) service
  • Building block for building distributed applications?
• Inter-AS trust relationships
  • Ossification of the Inter-AS interface – cannot be solved by a protocol!
• Impact ⇐ Applications ⇐ Business opportunities ($)
  • What user problem cannot be solved today?
• "The core challenge of CS ... is a conceptual one, viz., what (abstract) mechanisms we can conceive without getting lost in the complexities of our own making." - Dijkstra

For his vision for networking in 30 years, Ken suggested that:

• IP addresses will still be in use
  • but visible only at interfaces between different owners' infrastructures
• Network infrastructure might consist of access ASes + separate core networks operated by the "Big Five".
• Users might communicate via direct brain interfaces with AI systems.

Dirk Kutscher: Principled Approach to Network Programmability

I offered the perspective of introducing a principled approach to programmability that could provide better programmability (for humans and AI), based on more powerful network abstractions.

Previous work in SDN with protocols such as OpenFlow and dataplane programming languages such as P4 have only scratched the surface of what could be possible. OpenFlow was a great first idea, but it was fundamentally constrained by the IP and Ethernet-based abstractions that were built into it. It can be used for programming some applications in that domain, such as firewalls, virtual networking etc., but the idea of continuous innovation has not really materialized.

Similarly, P4 was advertized as an enabler for new levels of dataplane programmability, but even simple systems such as NetCache have to go to quite some extend to achieve minimal functionality for a proof-of-concept. Another P4 problem that is often reported is the hardware heterogeneity so that universal programmability is not really possible. In my opinion, this raises some questions with respect to applicability of current dataplane programming for in-network computing. A good example of a more productive application of P4 is the recent SIGCOMM paper on NetClone that describes as fast, scalable, and dynamic request cloning for microsecond-Scale RPCs. Here P4 is used as an accelerator for programming relatively simple functionality (protocol parsing, forwarding).

This may not be enough for future universal programmability though. During the panel discussion, I drew an analogy to computer programming language. We are not seeing the first programming language and IDEs that are designed from the ground up for better AI. What would that mean for network programmability? What abstractions and APIs would we need?

In my opinion, we would have to take a step back and think about the intended functionality and the required observability for future (automated) network programmability that is really protocol-independent. This would then entail more work on:

• the fundamental forwarding service (informed by hardware constraints);
• the telemetry approach;
• suitable protocol semantics;
• APIs for applications and management; and
• new network emulation & debugging approach (a long the lines of "network digital twin" concepts).

Overall, I am expecting new exiciting research in the direction of principled approaches to network programmability.

Jim Kurose: Open Research Infrastructures and Softwarization

Jim reminded us that the key reason Internet research flourished was the availability of open infrastructure with no incumbent providers initially. The infrastructure was owned by researchers, labs, and universities and allowed for a lot of experimentation.

This open infrastructure has recently been challenged by ossification with the rise of production ISP services at scale, and the emergence of closed ISPs, cellular carriers, hyperscalers operating large portion of the network.

As an example for emerging environments that offer interesting opportunities for experiments and new developments, Jim mentioned 4G/5G private networks, i.e., licensed spectrum created closed ecosystems – but open to researchers, creating opportunities for:

• innovation in private 5G networks such as Citizens Broadband Radio Service (CBRS) that could enables innovation in open, deployed systems and a democratization of 5G+ networks and edge applications;
• testbeds, such as Platforms for Advanced Wireless Research (PAWR); and
• the integration of WiFi, 5G as link-layer edge RANs.

Jim was also suggesting further opportunities in softwarization and programmability, such as (formal) methods for logical correctness and configuration management, as well as programmability to add services beyond the "minimal viable service", such as closed loop automatic control and management.

Finally Jim also mentioned opportunities in emerging new networks such as LEOs, IoT and home networks.

This is an introduction to our paper:

• Dirk Kutscher, Jeff Burke, Giuseppe Fioccola, Paulo Mendes; Statement: The Metaverse as an Information-Centric Network; 10th ACM Conference on Information-Centric Networking (ACM ICN '23); October 9 — 10, 2023, Reykjavik, Iceland; https://dl.acm.org/doi/10.1145/3623565.3623761; pre-print available at http://arxiv.org/abs/2309.09147

The Web Today

The Web today has a specific technical definition: it includes presentation layer technologies, protocols, agreed-upon ways of achieving certain semantics such as Representational State Transfer (REST), and security infrastructure. However, from a user perspective, it can be viewed as a universe of consistently navigable content and (occasionally) interoperable services. The user experience and architectural underpinnings have evolved in parallel and have influenced each other: for many end users, the Web and the network are synonymous. Rather than building up "Metaverse" as an application domain based on IP, we aim to explore "the Metaverse" as strongly intertwined with ICN, just as the modern concept of the Web and its technology stack are inseparable for a broad set of applications.

As a placeholder name for a range of new technologies and experiences, "the Metaverse" is even less well-defined than the Web. We adopt the commonly used concept of a shared, interoperable, and persistent XR. Some descriptions and early prototypes for social AR/VR systems suggest leveraging existing Internet and Web protocols to provide Metaverse services, without addressing the technical complexity and centralization of control required to provide the underlying cloud service infrastructure.

Metaverse as an Information-Centric Concept

Here, we do not take as given current designs and deployment models that consider the Metaverse as an overlay application with corresponding infrastructure dependencies, as this exacerbates the current gaps (and the resulting costs and technical complexity) between distributed applications and the underlying network architecture. Instead, we assume a fundamentally information/centric system in which most applications participate in granular 3D content exchange, context-aware integration with the physical world, and other Metaverse-relevant services.

"The Metaverse" is an information-centric concept that likely will become synonymous with the network itself. We argue that reciprocal design of the network and applications will open new opportunities for the deployment of Metaverse-suggestive experiences even today.

Experientially, this Metaverse is an extension of the Web into immersive XR modalities that are often aligned with physical space, as in augmented reality (AR). We conceive the Metaverse not only as a shared XR environment, but the next generation of the web, extending into 3D interaction/immersion and optionally overlaid on physical spaces. Instead of rendering data objects into a 2D page (within a tab within a window) on a device, we envision such objects being rendered into a shared 3D space, interacting among each other and with end users.

Architecturally, leveraging ICN concepts provides support for decentralized publishing, content interoperability and co-existence, based on general building blocks and not within separated application silos as today's initial prototypes. We claim that such properties are required to achieve the generally circulated visions of Metaverse systems, but are not achievable today because of the host- and connection-centric way in which the web operates and is presented to users in browsers.

ICN Capabilities

We point out four ICN capabilities critical to Metaverse concepts:

1. scalable and robust multi-destination communication, overcoming IP multicast challenges, such as inter-domain routing, scalability, and routing communication overhead;
2. leveraging wireless broadcast to support shared local views and low-latency interactivity without application-awareness in edge routers;
3. privacy, selective attention, content filtering, and autonomous interactions, as well as ownership and control on the publishing side; and
4. supporting in-network processing for objects replication and transformation.

Interactive Holographic Communication

For example, imagine interactive holographic communication consisting of participants' 3D video, spatial audio, and shared 3D documents. In ICN, such an application can represent virtual content as secure data objects and share them efficiently in a larger group of peers, fetching only the data necessary to reconstruct a suitable representation while being aware of the constraints of user devices and access networks.

Furthermore, while experiencing 3D objects shared by the group, each participant may also interact in the same XR environment with personal services such as wayfinding, messaging, and Internet of Things (IoT) device status. Interactions between private and shared 3D objects would be simplified if these objects use similar conventions but with different security. This concept is semantically well-aligned with ICN properties, particularly for security, as it revolves around object-level data exchange rather than hosts or channels. Integration and interoperability within a shared XR environment, without centralization, is challenging if one has to negotiate not only data interactions but also the underlying service connections and security relationship using host-centric paradigms. It also exacerbates the impact of intermittent connectivity on interactivity when the global network is required for functions such as rendezvous -- that are handled locally in ICN.

Creating Shared Environments

As a second example, consider creating a shared environment -- e.g., to pre-visualize engineering models of an aircraft – from a collection of collaboratively edited 3D documents. Imagine component documents interacting in a simulation. Documents can be modularized, linked, and overlaid in a web-like manner. Today, such cross-platform interoperability and visualization without centralized hubs is impractical, and it is difficult to create secure, granular data flows required for interaction between co-existing 3D elements to "bring them to life" in a virtual world. In an ICN approach, such modules could be independently authored and published, shared between applications, becoming building blocks of a richer, interacting system of user- and machine-generated content.

We introduce some technical challenges and research direction in our paper (link below).

Further Reading

The Metaverse as an Information-Centric Network

• Dirk Kutscher, Jeff Burke, Giuseppe Fioccola, Paulo Mendes; Statement: The Metaverse as an Information-Centric Network; 10th ACM Conference on Information-Centric Networking (ACM ICN '23); October 9 — 10, 2023, Reykjavik, Iceland; https://doi.org/10.1145/3623565.3623712; pre-print available at http://arxiv.org/abs/2309.09147
• Giuseppe Fioccola , Paulo Mendes , Jeff Burke , Dirk Kutscher;
  Information-Centric Metaverse; Internet Draft draft-fmbk-icnrg-metaverse-01; Work in Progress; July 2023
• Jeff Burke, Lixia Zhang, Dirk Kutscher; Named Data Microverse project
• Dirk Kutscher, Jeff Burke, Paulo Mendes, Michelle Munson, Todd Hodes; Named Data Metaverse Panel at NDNComm-2023
• Dirk Kutscher, Lixia Zhang, Jeff Burke, Dave Oran; IEEE MetaCom Workshop on Decentralized, Data-Oriented Networking for the Metaverse (DORM); IEEE Metacom-2023
• Dirk Kutscher, Dave Oran; Statement: RESTful Information-Centric Networking; ACM Conference on Information-Centric Networking (ICN 2022); Osaka, Japan; September 2022; https://dirk-kutscher.info/publications/icn-rest/

References

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• Erickson, L; Interoperability in the immersive web – part 1; https://hubs.mozilla.com/labs/interoperability-in-the-immersive-web/, Feb 2023.
• Fielding, R. T.; Architectural Styles and the Design of Network-based Software Architectures; PhD thesis, University of California, Irvine, 2000. http://www.ics.uci.edu/fielding/pubs/dissertation/top.htm
• Gruessing, J., and Dawkins, S; Media over quic - use cases and requirements for media transport protocol design; Internet-Draft https://datatracker.ietf.org/doc/draft-ietf-moq-requirements/, version 01; IETF Secretariat, July 2023.
• Jennings, C. F., Nandakumar, S., and Huitema, C. Quicr – media delivery protocol over quic. Internet-Draft https://datatracker.ietf.org/doc/draft-jennings-moq-quicr-proto/, version 01, IETF Secretariat, January 2023.
• LAMINA1. Decentralized system services for the open metaverse; https://uploads-ssl.webflow.com/63fe332d7b9ae4159d741e55/64499d8f08bd5bdd1fe6bce1_MaaS_Whitepaper_v1.0.pdf
• Moll, P., Patil, V., Wang, L., and Zhang, L.; The evolution of distributed dataset synchronization solutions in NDN: sok; In 9th ACM Conference on Information-Centric Networking; ICN 2022; Osaka Japan; September 19-21, 2022 (2022); https://dl.acm.org/doi/10.1145/3517212.3558092
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• NVIDIA. What is universal scene description; https://developer.nvidia.com/usd.
• Oran, D. R.; Considerations in the Development of a QoS Architecture for CCNx-Like Information-Centric Networking Protocols; RFC 9064; June 2021; https://datatracker.ietf.org/doc/rfc9064/
• Patil, V., Desai, H., and Zhang, L; Kua: A distributed object store over named data networking; In Conference on Information-Centric Networking, ICN 2022, Osaka Japan, September 19-21, 2022 (2022); https://dl.acm.org/doi/10.1145/3517212.3558083
• Radoff, J.; Metaverse interoperability, part 1: Challenges. https://medium.com/building-the-metaverse/metaverse-interoperabilitypart-1-challenges-716455ca439e, Apr 2022.
• Khronos Group; glTF runtime 3d asset delivery; https://www.khronos.org/gltf/
• Yu, Y., Afanasyev, A., Clark, D., claffy, k., Jacobson, V., and Zhang, L.; Schematizing trust in named data networking; In Proceedings of the 2nd ACM Conference on Information-Centric Networking (New York, NY, USA, 2015), ACMICN ’15, Association for Computing Machinery; https://dl.acm.org/doi/10.1145/2810156.2810170