RFC 8884 | ICN in Disaster Scenarios | October 2020 |
Seedorf, et al. | Informational | [Page] |
Information-Centric Networking (ICN) is a new paradigm where the network provides users with named content instead of communication channels between hosts. This document outlines some research directions for ICN with respect to applying ICN approaches for coping with natural or human-generated, large-scale disasters. This document is a product of the Information-Centric Networking Research Group (ICNRG).¶
This document is not an Internet Standards Track specification; it is published for informational purposes.¶
This document is a product of the Internet Research Task Force (IRTF). The IRTF publishes the results of Internet-related research and development activities. These results might not be suitable for deployment. This RFC represents the consensus of the Information-Centric Networking Research Group of the Internet Research Task Force (IRTF). Documents approved for publication by the IRSG are not a candidate for any level of Internet Standard; see Section 2 of RFC 7841.¶
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8884.¶
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This document summarizes some research challenges for coping with natural or human-generated, large-scale disasters. In particular, the document discusses potential research directions for applying Information-Centric Networking (ICN) to address these challenges.¶
Research and standardization approaches exist (for instance, see the work and discussions in the concluded IRTF DTN Research Group [dtnrg] and in the IETF DTN Working Group [dtnwg]). In addition, a published Experimental RFC in the IRTF Stream [RFC5050] discusses Delay-Tolerant Networking (DTN), which is a key necessity for communicating in the disaster scenarios we are considering in this document. 'Disconnection tolerance' can thus be achieved with these existing DTN approaches. However, while these approaches can provide independence from an existing communication infrastructure (which indeed may not work anymore after a disaster has happened), ICN offers key concepts, such as new naming schemes and innovative multicast communication, which together enable many essential (publish/subscribe-based) use cases for communication after a disaster (e.g., message prioritization, one-to-many delivery of messages, group communication among rescue teams, and the use cases discussed in Section 4). One could add such features to existing DTN protocols and solutions; however, in this document, we explore the use of ICN as a starting point for building a communication architecture that supports (somewhat limited) communication capabilities after a disaster. We discuss the relationship between the ICN approaches (for enabling communication after a disaster) discussed in this document with existing work from the DTN community in more depth in Section 3.3.¶
'Emergency Support and Disaster Recovery' is also listed among the ICN Baseline Scenarios in [RFC7476] as a potential scenario that 'can be used as a base for the evaluation of different ICN approaches so that they can be tested and compared against each other while showcasing their own advantages' [RFC7476] . In this regard, this document complements [RFC7476] by investigating the use of ICN approaches for 'Emergency Support and Disaster Recovery' in depth and discussing the relationship to existing work in the DTN community.¶
This document focuses on ICN-based approaches that can enable communication after a disaster. These approaches reside mostly on the network layer. Other solutions for 'Emergency Support and Disaster Recovery' (e.g., on the application layer) may complement the ICN-based networking approaches discussed in this document and expand the solution space for enabling communications among users after a disaster. In fact, addressing the use cases explored in this document would require corresponding applications that would exploit the discussed ICN benefits on the network layer for users. However, the discussion of applications or solutions outside of the network layer are outside the scope of this document.¶
This document represents the consensus of the Information-Centric Networking Research Group (ICNRG); it is not an IETF product and it does not define a standard. It has been reviewed extensively by the ICN Research Group (RG) members active in the specific areas of work covered by the document.¶
Section 2 gives some examples of what can be considered a large-scale disaster and what the effects of such disasters on communication networks are. Section 3 outlines why ICN can be beneficial in such scenarios and provides a high-level overview on corresponding research challenges. Section 4 describes some concrete use cases and requirements for disaster scenarios. In Section 5, some concrete ICN-based solutions approaches are outlined.¶
An enormous earthquake hit Northeastern Japan (Tohoku areas) on March 11, 2011 and caused extensive damages, including blackouts, fires, tsunamis, and a nuclear crisis. The lack of information and means of communication caused the isolation of several Japanese cities. This impacted the safety and well-being of residents and affected rescue work, evacuation activities, and the supply chain for food and other essential items. Even in the Tokyo area, which is 300 km away from the Tohoku area, more than 100,000 people became 'returner refugees' who could not reach their homes because they had no means of public transportation (the Japanese government has estimated that more than 6.5 million people would become returner refugees if such a catastrophic disaster were to hit the Tokyo area).¶
That earthquake in Japan also showed that the current network is vulnerable to disasters. Mobile phones have become the lifelines for communication, including safety confirmation. Besides (emergency) phone calls, services in mobile networks commonly being used after a disaster include network disaster SMS notifications (or SMS 'Cell Broadcast' [cellbroadcast]), available in most cellular networks. The aftermath of a disaster puts a high strain on available resources due to the need for communication by everyone. Authorities, such as the president or prime minister, local authorities, police, fire brigades, and rescue and medical personnel, would like to inform the citizens of possible shelters, food, or even of impending danger. Relatives would like to communicate with each other and be informed about their well-being. Affected citizens would like to make inquiries about food distribution centers and shelters or report trapped and missing people to the authorities. Moreover, damage to communication equipment, in addition to the already existing heavy demand for communication, highlights the issue of fault tolerance and energy efficiency.¶
Additionally, disasters caused by humans (i.e., disasters that are caused deliberately and willfully and have the element of human intent such as a terrorist attack) may need to be considered. In such cases, the perpetrators could be actively harming the network by launching a denial-of-service attack or by monitoring the network passively to obtain information exchanged, even after the main disaster itself has taken place. Unlike some natural disasters that are predictable to a small extent using weather forecasting technologies, may have a slower onset, and occur in known geographical regions and seasons, terrorist attacks almost always occur suddenly without any advance warning. Nevertheless, there exist many commonalities between natural and human-induced disasters, particularly relating to response and recovery, communication, search and rescue, and coordination of volunteers.¶
The timely dissemination of information generated and requested by all the affected parties during and in the immediate aftermath of a disaster is difficult to provide within the current context of global information aggregators (such as Google, Yahoo, Bing, etc.) that need to index the vast amounts of specialized information related to the disaster. Specialized coverage of the situation and timely dissemination are key to successfully managing disaster situations. We believe that network infrastructure capabilities provided by Information-Centric Networks can be suitable, in conjunction with application and middleware assistance.¶
Given a disaster scenario as described in Section 2, on a high level, one can derive the following (incomplete) list of corresponding technical challenges:¶
Several aspects of ICN make related approaches attractive candidates for addressing the challenges described in Section 3.1. Below is an (incomplete) list of considerations why ICN approaches can be beneficial to address these challenges:¶
There has been quite some work in the DTN (Delay-Tolerant Networking) community on disaster communication (for instance, see the work and discussions in the concluded IRTF DTN Research Group [dtnrg] and in the IETF DTN Working Group [dtnwg]). However, most DTN work lacks important features, such as publish/subscribe (pub/sub) capabilities, caching, multicast delivery, and message prioritization based on content types, which are needed in the disaster scenarios we consider. One could add such features to existing DTN protocols and solutions, and indeed individual proposals for adding such features to DTN protocols have been made (e.g., [Greifenberg2008] and [Yoneki2007] propose the use of a pub/sub-based multicast distribution infrastructure for DTN-based opportunistic networking environments).¶
However, arguably ICN -- having these intrinsic properties (as also outlined above) -- makes a better starting point for building a communication architecture that works well before and after a disaster. For a disaster-enhanced ICN system, this would imply the following advantages: a) ICN data mules would have built-in caches and can thus return content for interests straight on, b) requests do not necessarily need to be routed to a source (as with existing DTN protocols), instead any data mule or end user can in principle respond to an interest, c) built-in multicast delivery implies energy-efficient, large-scale spreading of important information that is crucial in disaster scenarios, and d) pub/sub extension for popular ICN implementations exist [COPSS2011], which are very suitable for efficient group communication in disasters and provide better reliability, timeliness, and scalability, as compared to existing pub/sub approaches in DTN [Greifenberg2008] [Yoneki2007] .¶
Finally, most DTN routing algorithms have been solely designed for particular DTN scenarios. By extending ICN approaches for DTN-like scenarios, one ensures that a solution works in regular (i.e., well-connected) settings just as well (which can be important in reality, where a routing algorithm should work before and after a disaster). It is thus reasonable to start with existing ICN approaches and extend them with the necessary features needed in disaster scenarios. In any case, solutions for disaster scenarios need a combination of ICN-features and DTN-capabilities.¶
This section describes some use cases for the aforementioned disaster scenario (as outlined in Section 2) and discusses the corresponding technical requirements for enabling these use cases.¶
After a disaster strikes, citizens want to confirm to each other that they are safe. For instance, shortly after a large disaster (e.g., an earthquake or a tornado), people have moved to different refugee shelters. The mobile network is not fully recovered and is fragmented, but some base stations are functional. This use case imposes the following high-level requirements: a) people must be able to communicate with others in the same network fragment and b) people must be able to communicate with others that are located in different fragmented parts of the overall network. More concretely, the following requirements are needed to enable the use case: a) a mechanism for a scalable message forwarding scheme that dynamically adapts to changing conditions in disconnected networks, b) DTN-like mechanisms for getting information from one disconnected island to another disconnected island, c) source authentication and content integrity so that users can confirm that the messages they receive are indeed from their relatives or friends and have not been tampered with, and d) the support for contextual caching in order to provide the right information to the right set of affected people in the most efficient manner.¶
It can be observed that different key use cases for disaster scenarios imply overlapping and similar technical requirements for fulfilling them. As discussed in Section 3.2, ICN approaches are envisioned to be very suitable for addressing these requirements with actual technical solutions. In [Robitzsch2015], a more elaborate set of requirements is provided that addresses, among disaster scenarios, a communication infrastructure for communities facing several geographic, economic, and political challenges.¶
This section outlines some ICN-based research approaches that aim at fulfilling the previously mentioned use cases and requirements (Section 5.1). Most of these works provide proof-of-concept type solutions, addressing singular challenges. Thus, several open issues remain, which are summarized in Section 5.2.¶
The research community has investigated ICN-based solutions to address the aforementioned challenges in disaster scenarios. Overall, the focus is on delivery of messages and not real-time communication. While most users would probably like to conduct real-time voice/video calls after a disaster, in the extreme scenario we consider (with users being scattered over different fragmented networks as can be the case in the scenarios described in Section 2), somewhat delayed message delivery appears to be inevitable, and full-duplex real-time communication seems infeasible to achieve (unless users are in close proximity). Thus, the assumption is that -- for a certain amount of time at least (i.e., the initial period until the regular communication infrastructure has been repaired) -- users would need to live with message delivery and publish/subscribe services but without real-time communication. Note, however, that a) in principle, ICN can support Voice over IP (VoIP) calls; thus, if users are in close proximity, (duplex) voice communication via ICN is possible [Gusev2015], and b) delayed message delivery can very well include (recorded) voice messages.¶
The proposed solutions in Section 5.1 investigate how ICN approaches can, in principle, address some of the outlined challenges. However, several research challenges remain open and still need to be addressed. The following (incomplete) list summarizes some unanswered research questions and items that are being investigated by researchers:¶
This document does not define a new protocol (or protocol extension) or a particular mechanism; therefore, it introduces no specific new security considerations. General security considerations for ICN, which also apply when using ICN techniques to communicate after a disaster, are discussed in [RFC7945].¶
The after-disaster communication scenario, which is the focus of this document, raises particular attention to decentralized authentication, content integrity, and trust as key research challenges (as outlined in Section 3.1). The corresponding use cases and ICN-based research approaches discussed in this document thus imply certain security requirements. In particular, data origin authentication, data integrity, and access control are key requirements for many use cases in the aftermath of a disaster (see Section 4).¶
In principle, the kinds of disasters discussed in this document can happen as a result of a natural disaster, accident, or human error. However, intentional actions can also cause such a disaster (e.g., a terrorist attack, as mentioned in Section 2). In this case (i.e., intentionally caused disasters by attackers), special attention needs to be paid when re-enabling communications as temporary, somewhat unreliable communications with potential limited security features may be anticipated and abused by attackers (e.g., to circulate false messages to cause further intentional chaos among the human population, to leverage this less secure infrastructure to refine targeting, or to track the responses of security/police forces). Potential solutions on how to cope with intentionally caused disasters by attackers and on how to enable a secure communications infrastructure after an intentionally caused disaster are out of scope of this document.¶
The use of data-centric security schemes, such as 'Ciphertext-Policy Attribute Based Encryption' (as mentioned in Section 5.1), which encrypt the data itself (and not the communication channel), in principle, allows for the transmission of such encrypted data over an unsecured channel. However, metadata about the encrypted data being retrieved still arises. Such metadata may disclose sensitive information to a network-based attacker, even if such an attacker cannot decrypt the content itself.¶
This document has summarized research directions for addressing these challenges and requirements, such as efforts in data-centric confidentiality and access control, as well as recent works for decentralized authentication of messages in a disaster-struck networking infrastructure with nonfunctional routing links and limited communication capabilities (see Section 5).¶
This document has outlined some research directions for ICN with respect to applying ICN approaches for coping with natural or human-generated, large-scale disasters. The document has described high-level research challenges for enabling communication after a disaster has happened, as well as a general rationale why ICN approaches could be beneficial to address these challenges. Further, concrete use cases have been described and how these can be addressed with ICN-based approaches has been discussed.¶
Finally, this document provides an overview of examples of existing ICN-based solutions that address the previously outlined research challenges. These concrete solutions demonstrate that indeed the communication challenges in the aftermath of a disaster can be addressed with techniques that have ICN paradigms at their base, validating our overall reasoning. However, further, more-detailed challenges exist, and more research is necessary in all areas discussed: efficient content distribution and routing in fragmented networks, traffic prioritization, security, and energy efficiency. An incomplete, high-level list of such open research challenges has concluded the document.¶
In order to deploy ICN-based solutions for disaster-aftermath communication in actual mobile networks, standardized ICN baseline protocols are a must. It is unlikely to expect all user equipment in a large-scale mobile network to be from the same vendor. In this respect, the work being done in the IRTF ICNRG is very useful as it works toward standards for concrete ICN protocols that enable interoperability among solutions from different vendors. These protocols -- currently being developed in the IRTF ICNRG as Experimental specifications in the IRTF Stream -- provide a good foundation for deploying ICN-based, disaster-aftermath communication and thereby address key use cases that arise in such situations (as outlined in this document).¶
This document has no IANA actions.¶
The authors would like to thank Ioannis Psaras for useful comments. Also, the authors are grateful to Christopher Wood and Daniel Corujo for valuable feedback and suggestions on concrete text for improving the document. Further, the authors would like to thank Joerg Ott and Dirk Trossen for valuable comments and input, in particular, regarding existing work from the DTN community that is highly related to the ICN approaches suggested in this document. Also, Akbar Rahman provided useful comments and suggestions, in particular, regarding existing disaster warning mechanisms in today's mobile phone networks.¶
This document has been supported by the GreenICN project (GreenICN: Architecture and Applications of Green Information-Centric Networking), a research project supported jointly by the European Commission under its 7th Framework Program (contract no. 608518) and the National Institute of Information and Communications Technology (NICT) in Japan (contract no. 167). The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the GreenICN project, the European Commission, or the NICT. More information is available at the project website: http://www.greenicn.org/.¶
This document has also been supported by the Coordination Support Action entitled 'Supporting European Experts Presence in International Standardisation Activities in ICT' (StandICT.eu) funded by the European Commission under the Horizon 2020 Programme with Grant Agreement no. 780439. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the European Commission.¶