Upcoming Wireless Networks and New Challenges Generalities Mesh networks Vehicular networks Security and Cooperation in Wireless Networks Georg-August University Göttingen
Introduction Upcoming wireless networks: – Personal communications: • Wireless mesh networks • Hybrid ad hoc networks • Mobile ad hoc networks – Vehicular networks – Sensor networks – RFID (Radio Frequency IDentification) – Mobility in the Internet Georg-August University Göttingen Upcoming Wireless Networks and New Challenges 2
Wireless mesh networks Mesh network: – One Wireless Hot Spot (WHS): connected to the Internet – Several Transit Access Points (TAPs): functioning as relay stations Between WHS and MSs – Mobile Stations Georg-August University Göttingen Upcoming Wireless Networks and New Challenges 3
Wireless mesh networks Easy to deploy: – Single connection point to the Internet Providing internet connectivity in a sizable geographic area: – Much lower cost than classic WiFi networks Interesting to us because they contain some features and vulnerabilities of future networks (such as multi-hopping wireless) and are still in their early deployment phase Performance (in this case fairness) and security are closely related Not yet ready for wide-scale deployment: – Severe capacity and delay constraints • Due to being wireless and multi-hop are prone to interference – But technology will be able to overcome: Multi-radio and multi- channel – Lack of security guarantees Georg-August University Göttingen Upcoming Wireless Networks and New Challenges 4
Hybrid ad hoc networks Hybrid ad hoc networks or multi-hop cellular networks: – No relay stations: assigning the relay task to other mobile stations – Other mobile stations relay the traffic Problem of power management: as no priori planning is possible Georg-August University Göttingen Upcoming Wireless Networks and New Challenges 5
Mobile ad hoc networks Mobile ad hoc networks (MANETs): – One step further: removing completely the infrastructure – Mobile ad hoc networks in hostile environments – In self-organized mobile ad hoc networks the mobile stations relay each other’s traffic – Mobile ad hoc networks: a very active research field Georg-August University Göttingen Upcoming Wireless Networks and New Challenges 6
Mobile ad hoc networks It is important to distinguish between two kinds of Ad Hoc Networks: Mobile ad hoc networks in hostile environments: – Presence of a strong attacker is likely: military networks – Security challenges: • Secure routing • Prevention of traffic analysis • Resistance of a captured device to reverse engineering and key retrieval. Self-organized mobile ad hoc networks: – Small scale applications, e.g. a group of people can establish a network using their PDAs or laptops where no infrastructure is available – No authority in the initialization phase – Nodes have to figure out how to secure the communications – Selfishness can be a serious issue: • Nodes may selfishly refuse to forward packets • Greedily overuse the common channel Georg-August University Göttingen Upcoming Wireless Networks and New Challenges 7
Sensor networks Collecting data about physical phenomena (light, temperature, humidity, acceleration, etc.) in addition to communication and computing capabilities Large number of sensor nodes, a few base stations – Base stations much more powerful than sensor nodes Sensors are usually battery powered: – Main design criteria: reduce the energy consumption Multi-hop communication reduces energy consumption: – Overall energy consumption can be reduced if packets are sent in several smaller hops instead of one long hop • Smaller range of transmission • Less interference -> Fewer re-transmissions are needed due to collisions Georg-August University Göttingen Upcoming Wireless Networks and New Challenges 8
Sensor networks Security requirements: – Integrity (data packets from sensor nodes to the sink and control packets from the sink to the nodes) – Confidentiality – Availability (specially in life critical applications such as people’s health monitoring) Special conditions: – Energy consumption (limited power) – Computing and storage capacity of sensors is limited – Access to the sensors cannot be monitored and therefore they can be corrupted by the adversary: then the adversary can learn the content of the memory the cryptographic keys or modify the behavior of the nodes. Georg-August University Göttingen Upcoming Wireless Networks and New Challenges 9
RFID A wireless technology to enable identification of objects and people Current applications: management of books at libraries, toll-payment at highways, access control to buildings, etc. RFID systems: – RFID tags – RFID readers – Back-end databases RFID tag: microchip and antenna – Active: have battery – Passive: harvest energy from the reader's signal (reflecting its signal) RFID reader: – Reads the identifying information out from nearby RFID tags Georg-August University Göttingen Upcoming Wireless Networks and New Challenges 10
Mobility in the Internet The growing mobility of hosts has led the Internet community to reconsider the overall organization of the network (Mobile IPv6) When a node changes its location: its address changes Mobile IP: solves this problem at the IP layer Georg-August University Göttingen Upcoming Wireless Networks and New Challenges 11
Mobility in the Internet The home agent is a router permanently aware of the current location of the nodes that are away from home Care-of address: Address used by the mobile node while it is attached to a foreign link Binding: Association of a care-of address with a home address (stored at home agents and correspondent nodes) Two modes of mobility supported by IPv6: – Bidirectional tunneling: • Mobile node tunnels the packets for the correspondent node through its home agent • Home agent tunnels the packets to the mobile node via its care-of address – Route optimization: • Mobile node registers its current address binding with the correspondent node • Packets are sent directly to the mobile node's care-of address • Use the optimal route between the mobile and correspondent node Georg-August University Göttingen Upcoming Wireless Networks and New Challenges 12
Mobility in the Internet Attacks: – Address stealing: • If binding updates were not authenticated: an attacker could send spoofed binding updates: A is sending packets to B, then the attacker sends a malicious binding update to A with the care-of- address of C to redirect the packet flow to C. – DoS attacks exploiting binding update protocols: • Exhausting the resources of the mobile node or the correspondent node by sending spoofed IP packets that trigger a large number of binding update protocol instances Georg-August University Göttingen Upcoming Wireless Networks and New Challenges 13
Mobility in the Internet Protection mechanism against address stealing: Return Routability (RR) – Non-cryptographic solution – Makes the attack much more difficult – Assumption of an uncorrupted routing infrastructure Mobile Node MN checks the routability to • the Correspondent Node CN: (a) via the Home Agent HA (HoTI) (b) directly (CoTI) CN replies to both of them: HoT and CoT • Georg-August University Göttingen Upcoming Wireless Networks and New Challenges 14
Return Routability Once MN has received both HoT and CoT: – MN sends a Binding Update to CN Protection mechanism against DoS attacks: – Each node can set a limit on the amount of resources (time, memory, bandwidth) devoted to processing binding updates Georg-August University Göttingen Upcoming Wireless Networks and New Challenges 15
Wireless Mesh Networks Wired Access Point (WAP) Transit Access Point (TAP) (b) A Mesh Network (a) A WiFi Network WMNs allow a fast, easy and inexpensive network deployment. However, the lack of security guarantees slows down the deployment of WMNs Georg-August University Göttingen 16 Upcoming Wireless Networks and New Challenges
A Typical Communication in WMNs WHS MS TAP 2 TAP 1 TAP 3 Several verifications need to be performed: – WHS has to authenticate the MS. – MS has also to authenticate the TAPs – Each TAP has to authenticate the other TAPs in the WHS – The data sent or received by MS has to be protected (e.g., to ensure data integrity, non-repudiation and/or confidentiality). Performing these verifications has to be efficient and lightweight, especially for the MS. Georg-August University Göttingen 17 Upcoming Wireless Networks and New Challenges
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