Semantic Addressing and Routing for Future Networks (SARNET-21) Workshop Report
draft-galis-irtf-sarnet21-report-00

IRTF                                                            A. Galis
Internet-Draft                                 University College London
Intended status: Informational                                    D. Lou
Expires: December 30, 2021          Huawei Technologies Duesseldorf GmbH
                                                           June 28, 2021

Semantic Addressing and Routing for Future Networks (SARNET-21) Workshop
                                 Report
                  draft-galis-irtf-sarnet21-report-00

Abstract

   This document provides an overview of the "Semantic Addressing and
   Routing for Future Networks" workshop (SARNET-21), which took place
   on June 10, 2021, in Paris, France and online as part of the IEEE
   International Conference on High-Performance Switching and Routing.
   The main goal of the SARNET-21 workshop was to explore, together with
   the research community, the use cases and network requirements in the
   domain of semantic addressing and routing, and identify potential
   research challenges to be tackled in the future.

   Note that this document is a report on the proceedings of the
   SARNET-21 workshop compiled by the authors.  It captures the views
   and positions of the workshop participants as expressed during the
   workshop.

Status of This Memo

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   This Internet-Draft will expire on December 30, 2021.

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Copyright Notice

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Workshop Agenda . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Discussions . . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Technical Presentations . . . . . . . . . . . . . . . . .   4
     3.2.  Panel on the Impact on Future Networks of Semantic
           Addressing and Routing  . . . . . . . . . . . . . . . . .   5
   4.  Summary, Next Steps and Conclusions . . . . . . . . . . . . .   7
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   8
   8.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .   9
   9.  Informative References  . . . . . . . . . . . . . . . . . . .   9
   Appendix A.  SARNET-21 Technical Program Committee  . . . . . . .   9
   Appendix B.  Accepted Papers  . . . . . . . . . . . . . . . . . .  10
   Appendix C.  Workshop Materials . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   Various networks, such as IoT networks, industry networks, data-
   center networks, content distribution networks, satellite networks,
   etc., have been emerging for the past decade in the light of digital
   transformation.  These heterogeneous networks often adopt different
   architectures, topologies, as well as addressing and routing
   mechanisms.  The satellite network is a typical example of a highly
   dynamic topology in which mobile network nodes can cause stability
   issues to existing routing protocols.  IoT and manufacturing networks
   often adopt alternative addressing semantics that go beyond the
   network location defined in IPv4 and/or IPv6.

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   In simple terms, semantic addressing is about taking a regular
   address and assigning special meaning to some or all of the bits.
   Examples include multicast addresses, segment identifiers in segment
   routing, and network programming abstractions.  Although the specific
   semantics help to facilitate addressing and routing within the
   network, scalability challenges arise from providing the definition
   of those semantics, and the interconnection among such networks and
   the Internet.

   Several techniques have been proposed that modify/improve the default
   IP forwarding behaviors (such as least-cost path) to better meet the
   application requirements, based on additional information available
   in the packet (both in header and payload) and configurable policies
   in routers.  Collectively, these mechanisms are sometimes referred to
   as "Semantic Routing" [I-D.king-irtf-challenges-in-routing].  The
   alternative semantics used to make routing decisions, together with
   the IP addresses, could be applied to a network overlay [RFC7665], or
   can be directly embedded into the address field, which is the case in
   some limited domains [RFC8799] such as LoRaWAN deployments [LoRaWan].

   However, those ad-hoc solutions have been developed in a fragmented
   way, which creates interoperability issues between limited domains or
   between individual routers, and can lead to increased fragility or
   even security/privacy leakage.  A more holistic approach can design
   the architectural patterns based on semantic routing for future
   networks.

   In June 2021, the "Semantic Addressing and Routing for Future
   Networks" (SARNET-21) workshop was held as part of the IEEE
   International Conference on High-Performance Switching and Routing.
   This event was held in Paris, France and online.  The main goal of
   the SARNET-21 workshop was to explore the use cases and network
   requirements in the domain of semantic addressing and routing, and
   identify potential research challenges to be tackled in the future.
   The participants and audience of the workshop were drawn chiefly from
   the research community.

   This document is a report on the proceedings of the SARNET-21
   workshop compiled by the authors.  It captures the views and
   positions of the workshop participants as expressed during the
   workshop.

2.  Workshop Agenda

   The workshop&s goal was to invite the research community to
   collectively explore semantic addressing and routing and identify
   potential requirements and networking solutions.  Researchers and
   experts from industry and academia got the opportunity to share their

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   experiences and achievements by addressing the challenges mentioned
   above.

   The workshop also served as a venue to identify problems and to
   discover common interests that may turn into new work or into changes
   in the direction of ongoing work at the IETF and/or the Internet
   Research Task Force (IRTF).

   The SARNET-21 workshop received 19 submissions and accepted 10 papers
   based on a minimum of three peer reviews.  The accepted papers were
   presented in 3 technical sessions.  The accepted papers are listed in
   Appendix B.  In addition to the technical sessions, a keynote talk on
   "The Routing Challenges for Future Networks" was given by Prof.
   Olivier Bonaventure from Universite Catholique de Louvain
   (UCLouvain), and a panel discussion on "Semantic Addressing and
   Routing Impact on Future Networks" was moderated by Prof. Alex Galis
   from University College London (UCL).

3.  Discussions

3.1.  Technical Presentations

   The papers that were presented in the technical sessions cover the
   following topics:

   Semantic Addressing:  Alternative addressing semantics, beyond the
      use of traditional network locations in IPv4/IPv6, can overcome
      many of the limitations exhibited by existing technologies.
      Papers on this topic presented approaches ranging from non-IP
      addresses, which are automatically derived according to the
      network structure, IP addresses representing a space geo-location,
      and anycast addresses used as service identifiers.  In the case of
      network structure-oriented addresses, significant performance
      improvements have been demonstrated compared to IP with OSPF or
      BGP.  The use of space geo-location addresses provides support for
      highly dynamic network topologies (e.g., in low earth orbit (LEO)
      satellite constellations).  In contrast, anycast addresses have
      been shown to determine the best (instead of the closest) service
      instance in distributed edge compute scenarios.

   Semantic Routing:  Papers on this topic presented solutions in which
      routing decisions are based on semantic addresses and other fields
      in the packet, going beyond the traditional shortest path first
      algorithm.  One such paper used an application-layer overlay to
      act as the routing substrate to perform traffic differentiation
      and fine-grained per-flow traffic management based on tags added
      to packets that signify, for example, the desired QoS levels.
      Another example concerned the use of service names (simple binary

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      identifiers of fixed size) to route traffic within a domain, which
      improves service access in terms of network and service latency.

   Security:  Security was one of the capabilities that have been
      overlooked in the original design of the Internet.  Two papers in
      the workshop proposed solutions in this space.  The first was
      developed in the context of named data networking where
      decentralized identifiers are used to build self-verifiable
      content advertisements.  Based on these, routers can verify that a
      content advertisement originates from an authorized entity without
      requiring any trusted third party, thus preventing DoS attacks.
      The other paper presented an approach that overcomes privacy
      violations as a result of using location-oriented IP addresses.
      This is based on source routing with public-key cryptography to
      establish connections and simple private symmetric encryption in
      the data path that allows for fully stateless packet transmission
      between two endpoints in the Internet.

   Programmability:  Network programmability has been an instrumental
      topic for a while due to its benefits in terms of flexibility and
      adaptability.  Papers on this topic focused on using SDN to
      configure forwarding rules according to semantic routing policies
      (e.g., QoS), changing the forwarding behavior of a programmable
      data plane through P4, and using flexible virtualization
      technologies for the realization of network functions.

   Limited Domains:  Various limited domains have been targeted by
      papers presented at the workshop.  There took their unique
      characteristics and requirements into account when designing the
      respective solutions.  Included among these were satellite and
      vehicular networks that have highly dynamic topologies, industrial
      networks with strict QoS expectations, and IoT networks that
      involve efficient delivery of bulk data and short addresses.

3.2.  Panel on the Impact on Future Networks of Semantic Addressing and
      Routing

   A panel of experts was convened and chaired by Prof. Alex Galis:

   o  Christian Jacquenet (Orange, France)

   o  Rui Aguiar (University of Aveiro, Portugal)

   o  Adrian Farrel (Old Dog Consulting, UK)

   o  Mohamed Faten Zhani (ETS, Canada)

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   The panelists and audience had a fascinating and constructive
   discussion for about 2 hours.  The panelists, in their presentations,
   raised essential points including:

   o  Significant changes can make network operators nervous.  Hence,
      there is a need for robust standardization effort to ensure
      graceful and safe co-existence with legacy equipment and a clear
      migration path.

   o  The set of questions that research should address.

   o  Privacy and security are critical requirements for future
      addressing/routing solutions.

   o  Semantics tend to be service-specific.

   o  Routing protocols should be customized to the needs of the
      applications.

   During the session, the panelists expressed the opinion that although
   semantic routing also exists today to a certain degree (e.g., ECMP,
   IP Flex-algo, etc.), any change that will question decades of IP
   network operation will undoubtedly make operators nervous.  Any new
   addressing/routing system and framework will need to coexist with
   legacy gear and thus requires a robust standardization effort with
   one of the focal points on avoiding semantic leakage between routing
   domains/limited domains/slices/partitions on the Internet.

   While this is a fundamental topic, the panel recognized that the
   potential impacts and benefits of changing the addressing and routing
   system have been overlooked.  There is, hence, a need to revisit the
   origins of the Internet.  Given that the Internet architecture is
   composed of many limited domains interconnected by a transport layer
   and associated protocols, the panelists said that understanding what
   is happening with limited domains and why they exist will help us
   better understand the impact of semantic addressing and routing.  New
   protocols could be deployed and evaluated starting from such limited
   domains or network slices, where the effect is contained.  Due to its
   fragility, there was general consensus that care needs to be taken
   over any changes in the backbone of the Internet.

   As semantics is mainly service-specific standardized dynamic links
   between forwarding plane and services are instrumental.  As such
   standardized, safe deterministic network programmability and
   frameworks enabling semantic addressing and new routing protocols
   with guarantees are needed, also enabling cost-efficient solutions of
   (In-time and On-time) service-inferred performance management.

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   Another conclusion of the panel was there is a need to explore new
   routing technologies and protocols inside limited domains to deliver
   new capabilities and better QoS, enabling application-level
   innovation and precluding pollution between domains.  There was an
   observation that we are already re-using many protocols in limited
   domains that are currently used in the Internet, e.g., TCP/IP, BGP,
   etc.  While this is not a bad practice, it is necessary to clearly
   state their "private" nature.  For instance, BGP was used for routing
   in SIP, but it was given a new protocol ID.  The panelists said that
   if we design protocol extensions or entirely new protocols, we need
   to make them compatible to avoid distorting the Internet routing
   system.

   In terms of standardization, the panel concluded that researchers
   should be encouraged to communicate and exchange their research
   results.  Doing research in silos doesn't help the adoption of new
   technologies and protocols.  Fragmenting the problem and farming out
   the necessary engineering work to some existing silos standardization
   groups doesn't solve such systemic challenges either.  While
   permissionless innovation is a way to achieve agile development of
   new ideas and see them deployed in limited domains, the panel's view
   was that mutual review is essential for stable protocols, and
   widescale adoption is dependent on standardization.  The opinion that
   the IRTF is an effective and suitable place to facilitate this kind
   of discussion and progress was expressed.

4.  Summary, Next Steps and Conclusions

   Semantic addressing and routing is an exciting topic attracting a lot
   of attention from the research community.  New semantics have been
   invented and deployed in limited domains for new capabilities, better
   QoS, higher flexibility, and efficiency.  This enables incremental
   deployment of new technologies on "isolated islands" for innovative
   solutions that may or may not percolate to the whole Internet at a
   later stage.  However, it is challenging to securely and seamlessly
   connect a limited domain that uses new semantic addressing and
   routing capabilities to the Internet.  How will the new semantics
   will be treated in the Internet?  What if different devices have
   different semantic routing schemes?  Although non-scalable patch
   solutions could be used to solve this issue to some extent, this is
   more of a research problem rather than an engineering issue.  A
   "holistic" approach would be to look for potential architectural
   patterns or common building blocks to facilitate the interconnection
   between the limited domain and Internet.

   To conclude, the area of semantic addressing and routing deserves
   further research.  The output of this research can be published and
   presented at future workshops, but equally important is the

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   standardization effort that should be invested to ensure stability,
   scalability, and interoperability of potential solutions.

   Based on the open discussions among the workshop participants and our
   overall experience with the workshop, several observations have been
   made, which could lead to some actions as follows:

   SARNET-22:  SARNET-21 was the first time the workshop had been held,
      and was a successful event.  It has attracted high-quality
      technical papers, was very well attended, and featured lively
      discussions.  The outcomes suggest holding a follow-up workshop
      next year.

   Research questions:  Important research challenges have been
      identified by workshop participants, which deserve careful
      consideration.  A coordinated effort in addressing these
      challenges could constitute a meaningful target.  The challenges
      will continue to be documented in
      [I-D.king-irtf-challenges-in-routing], and a discussion venue is
      provided by the SARAH email list [Sarah].

   IRTF RG:  Several participants, including panelists, expressed the
      need for coordinated research and a concerted standardization
      effort.  A research group could facilitate such activities
      umbrella of the IRTF that might lead to new work in the IETF.

5.  Security Considerations

   This document is a workshop report and has no direct impact on
   security.  Many of the ideas in the papers and presentations
   discussed at the workshop could have different security impacts.
   Each workshop paper should be read for its own security
   considerations.  The security consequences of semantic addressing and
   routing demand further research.

6.  IANA Considerations

   This document has no IANA actions.

7.  Acknowledgements

   The authors would like to thank the distinguished keynote speaker,
   panelists, paper presenters, workshop participants for the exciting
   presentations and discussions, and the Technical Program Committee
   members who contributed their time to provide high-quality reviews.
   The workshop organizers would also like to thank the HPSR-21
   conference organizers for hosting the workshop in excellent
   facilities in Paris, France.

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8.  Contributors

   TBD

9.  Informative References

   [I-D.king-irtf-challenges-in-routing]
              King, D., Dang, J., and A. Farrel, "Challenges for the
              Internet Routing Infrastructure Introduced by Changes in
              Address Semantics", draft-king-irtf-challenges-in-
              routing-02 (work in progress), May 2021.

   [LoRaWan]  The LoRa Alliance, "The Long Range WAN Link Layer
              Specification", Specification v1.0.4, <https://lora-
              alliance.org/resource_hub/lorawan-104-specification-
              package/>.

   [RFC7665]  Halpern, J., Ed. and C. Pignataro, Ed., "Service Function
              Chaining (SFC) Architecture", RFC 7665,
              DOI 10.17487/RFC7665, October 2015,
              <https://www.rfc-editor.org/info/rfc7665>.

   [RFC8799]  Carpenter, B. and B. Liu, "Limited Domains and Internet
              Protocols", RFC 8799, DOI 10.17487/RFC8799, July 2020,
              <https://www.rfc-editor.org/info/rfc8799>.

   [Sarah]    "Semantic Address Routing and Hardware", Email discussion
              list SARAH, <https://www.jiscmail.ac.uk/cgi-bin/WA-
              JISC.exe?SUBED1=SARAH&A=1>.

Appendix A.  SARNET-21 Technical Program Committee

   o  Olivier Bonaventure, UCLouvain, Belgium

   o  Filip De Turck, Ghent University, Belgium

   o  Ning Wang, University of Surrey, UK

   o  Xiaoming Fu, Gottingen University, Germany

   o  Tarik Taleb, Aalto University, Finland

   o  Maziar Nekovee, University of Sussex, UK

   o  Miguel Rio, University College London, UK

   o  Dirk Trossen, Huawei Technologies, Germany

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   o  Michael Menth, University Tuebingen, Germany

   o  Jon Crowcroft, Cambridge University, UK

   o  Lefteris Mamatas, University of Macedonia, Greece

   o  Albert Cabellos-Aparicio, Universitat Politecnica de Catalunya,
      Spain

   o  Noura Liman, University of Waterloo, Canada

   o  Stefano Secci, CNAM, France

   o  Akihiro Nakao, University of Tokyo, Japan

   o  Mohamed Faten Zhani, ETS, Canada

   o  Luigi Iannone, Huawei Technologies, France

   o  Cristel Pelsser, University of Strassbourg, France

   o  Michele Nogueira, Federal University of Minas Gerais, Brazil

   o  Leonardo Linguaglossa, Telecom Paris, France

   o  Lisandro Zambenedetti Granville, Federal University of Rio Grande
      do Sul, Brazil

Appendix B.  Accepted Papers

   The following 10 papers were presented at the workshop (listed in
   presentation order):

   o  Paolo Bellavista, Mattia Fogli, Luca Foschini, Carlo Giannelli,
      Lorenzo Patera, Cesare Stefanelli, "QoS-Enabled Semantic Routing
      for Industry 4.0 based on SDN and MOM Integration"

   o  Yizhou Li, Zifa Han, Shuheng Gu, Guanhua Zhuang, Feng Li,
      "Dyncast: Use Dynamic Anycast to Facilitate Service Semantics
      Embedded in IP address"

   o  Gao Zheng, Ning Wang, Rahim Tafazolli, XinPeng Wei, Jinze Yang,
      "Virtual Data-Plane Addressing for SDN-based Space and Terrestrial
      Network Integration"

   o  Ryota Kawashima, "A Vision to Software-Centric Cloud Native
      Network Functions: Achievements and Challenges"

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   o  Rene Glebke, Dirk Trossen, Ike Kunze, Zhe Lou, Jan Rueth, Mirko
      Stoffers and Klaus Wehrle, "Service-based Forwarding via
      Programmable Dataplanes"

   o  Paul Almasan, Jose Suarez-Varela, Bo Wu and Shihan Xiao, Pere
      Barlet-Ros and Albert Cabellos-Aparicio, "Towards Real-Time
      Routing Optimization with Deep Reinforcement Learning: Open
      Challenges"

   o  Mays AL-Naday, Irene Macaluso, "Flexible Semantic-based Data
      Networking for IoT Domains"

   o  Nikos Fotiou, Yannis Thomas, Vasilios A.  Siris, George Xylomenos
      and George C.  Polyzos, "Securing Named Data Networking routing
      using Decentralized Identifiers"

   o  Francesco Tusa, David Griffin, Miguel Rio, "Private Routing in the
      Internet"

   o  Nirmala Shenoy, Shreyas Chandraiah, Peter Willis, "A Structured
      Approach to Routing in the Internet"

Appendix C.  Workshop Materials

   A link to a repository of workshop materials will be provided in a
   future version of this document.

Authors' Addresses

   Alex Galis
   University College London
   UK

   Email: a.galis@ucl.ac.uk

   David Lou
   Huawei Technologies Duesseldorf GmbH
   Germany

   Email: zhe.lou@huawei.com

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