Survivable Mobile Wireless Networks: Issues, Challenges, and Research Directions

1. Survivable Mobile Wireless Networks: Issues, Challenges, and Research Directions Regina Rosales Hain, Alden W.Jackson, David Levin, Ram Ramanathan, and John Zao BBN Technologies WiSe’02, Sept. 28, 2002, Atlanta, Georgia, USA. Presented by Derek K.D. Jiang

2. Outline • Introduction • Definition of Survivability • Survivable connectivity • Survivable communication • Survivable technologies • Conclusion OPLab, Institute of IM, NTU

3. Introduction • This paper is a survey of the issues, challenges, and proposed research direction in survivable mobile wireless network. • Survivability consists not only of robustness against natural faults or misconfigurations, but also failures induced by malicious adversaries. OPLab, Institute of IM, NTU

4. Introduction Definition of Survivability Introduces and defines survivable networking and its aspects. Discusses establishing and maintaining network connectivity. Survivable Connectivity Argues that we should expect a challenging mobile wireless communication environment. Survivable Communication Survivable Technologies Discusses adaptive networking OPLab, Institute of IM, NTU

5. Definition of Survivability • Traditional security research • Primarily focused on the protection from attacks other than continued correct operation under attacks. • Faults are assumed to be independent and random. • Survivability research • The presence of intelligent adversarial attacks significantly challenge the conventional models. • Software and protocol vulnerability become more important considerations. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

6. Definition of Survivability • The definition we use here is from Software Engineering Institute : • 1. Survivability is the capability of a system to fulfill its mission in a timely manner, even in the presence of attacks or failures. • 2. The focus of survivability is on delivery of essential services and preservation of essential assets. • 3. Survivability depends on four key capabilities, “the four Rs”: resistance, recognition, recovery, and refinement. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

7. Military Network Survivability • Using wireless networking technologies to support military operations imposes survivability on: • 1. Transmission Security (TRANSEC) ─ the protection at physical, medium access and data link layers from radio signal detection, jamming, control/user data acquisition, and eavesdropping. • 2. Communication Security (COMSEC) ─ the protection of data to achieve CIA, non-repudiation, anti-replay, traffic analysis countermeasures. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

8. Military Network Survivability • Using wireless networking technologies to support military operations imposes survivability on: • 3. Authorization and Access Control ─ the support of multi-level security measures by implementing identity or role based access control. • 4. Network Infrastructure Protection ─ the protection of network management infrastructure from both passive and active attacks, rogue AP, illegal access to message. • 5. Robustness and efficiency. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

9. Cellular Network Survivability • Focused primarily on infrastructure survivability other than malicious attacks. • Vulnerability : • Network upgrade, especially involving software. • Rapid evolution leads to learning-curve problem. • Single point of failure. • Poor management tool. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

10. Low Probability of Detection • For most military ad hoc networks the ability to low probability of detection, interception, and exploitation (LPD/LPI/LPE) is of paramount importance. • Survivability is enhanced when the network is stealthy to potential adversaries. • The tradeoff of lower transmission power between adversaries and legitimate users. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

11. Survivable topological connectivity • Reducing transmission power limits the range of inter-node links used for multi-hop routing and also increasing the probability of the network becoming partitioned. • How can we reduce power while maintaining desired connectivity? Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

12. Survivable topological connectivity • We must adaptively adjust transmit powers of nodes in response to mobility. • Research : optimize certain power metrics while adhering to certain connectivity constrains. • Power metrics • minimize the maximum (or average) power used by the network. • Maximum power and average power. • Connectivity constrains • Tradeoff between robust connectivity and LPD. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

13. Survivable communication • Some situations where the environment is so challenging that ideal connectivity is impossible. • Channel condition (noise or jamming) • High mobility • We should expect and exploit those conditions: • Asymmetric links • Weak connectivity • Episodic connectivity Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

14. Asymmetric channel connectivity • Several ad hoc routing protocol expressly prohibit unidirectional routing based on the performance consideration. • In tactical network may require the use of asymmetric and unidirectional links • Secrete information in radio-silent mode. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

15. Unstable end-to-end paths • The eventual stability model of ad hoc routing assumes that routing converges eventually after partitioning. Under this model, a complete path to destination must exist at a given time. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

16. Unstable end-to-end paths • Ad hoc routing protocols can be categorized into three • Table-driven (Proactive), ex. CSGR, WRP • On-demand (Reactive), ex. DSR, ADOV • Hybrid, ex. ZRP • This model is used by on-demand routing as well as table-driven protocols. • Challenges to this model • Range limitations imposed by LPI/LPD concerns. • Intermittent and/or targeted jamming can disrupt routing converge. • High mobility is another aspect. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

17. Unstable end-to-end paths • The eventual connectivity model relaxes the traditional assumptions so that communication can proceed along partial segments of paths between communicating nodes. • There is no need to require that a complete physical path between communicating processes exist. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

18. Unstable end-to-end paths • Information progresses as far as possible, along whatever paths possible, until it reaches its destination. Make use of the concept of store-and-forward, and require modifying the typical forwarding behavior of dropping packets. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

19. Unstable end-to-end paths • This requires changes to current forwarding mechanisms. • The unavailable link should be marked in a new field in the forwarding table. • Requiring additional buffers at nodes to store packets and algorithms to determine which data is dropped when the buffers are full • Support multiple routing approaches at the same node to switch these two modes. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

20. Nomadicity V.S. Mobility • Mobility • Tries to maintain active sessions. • Continuous access to preconfigured infrastructure is assumed. • Nomadicity • Assumes constant movement. • Anticipates disconnected operation as the norm. • Applications are expected to tolerate disconnection during movement. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

21. Nomadicity V.S. Mobility • Addressing problem in both aspects • The address is assigned once and held as long as possible, or the node acquire a new address when moving to a different subnetwork. • Issue • When multiple addresses are available, the issue lies in whether we can seamlessly and securely migrate sessions when readdressing due to mobility. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

22. Routing under high mobility • In the case where mobility is highly frequent, it is necessary to use knowledge of the location and trajectories of nodes to predict future location. • Trajectory routing uses trajectories to compute destination node locations. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

23. Routing under high mobility • When the trajectory is not deterministic, the need for current location can be mitigated by multicast sprayingof information into a region that the node can be expected with high probability. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

24. Exploiting mobility to achieve connectivity • It is possible to exploit mobility to communicate by means of the two ways below. • Movement control can be used to exert control on other nodes into the range that a path toward the destination exists. • Mobile node can store-and-haul packets toward their destination by physically transporting the data. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

25. Adaptive and agile networking • Some technology centric thrusts to adapt to dynamic environments and to achieve connectivity. • Topological versus Geographical routing • Geographical routing techniques have proposed for wireless and sensor networks. • No routing-table, no overhead to find or update routes • Position required, Determining position via external service, and internal search-process. • Static wired infrastructure tends to be better suited to topological approaches. • Survivable nodes must support both strategies. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

26. Adaptive and agile networking • Adaptive nodes and networks can be achieved by active networking technology. • The application of the technology to mobile wireless networking allows • Dynamic selection of MAC and network layer parameters • The ability to dynamically provision and negotiate algorithms and select entire protocols based application requirement and the communication environment. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

27. Adaptive and agile networking • Advantages of active networking • Eliminate the need to standardize the entire protocols and algorithms. • Need not hard-code them into nodes. • Only a framework for node discovery and protocol negotiation need to be pre-determined. Definition of Survivability Survivable Connectivity Survivable Communication Survivable Technologies OPLab, Institute of IM, NTU

28. Conclusion • Significant progress has been made toward survivable network, however, further work needs to be done to understand the tradeoffs against stealth requirement (LPI/LPD/LPE). • Challenge channel condition should be regarded as a norm, similarly, mobility must be expected and exploited to enhance survivability. • Since it is impossible to predict the communication environment, it is critical that network nodes and protocols can adapt to the variation. OPLab, Institute of IM, NTU

29. Thanks for your listening OPLab, Institute of IM, NTU