Wireless Hotspots Current Challenges and Future Directions Mobile

Wireless Hotspots: Current Challenges and Future Directions Mobile Networks and Applications 2005 Presented by An Dong-hyeok CNLAB at KAIST

Contents 1. Introduction 2. An example scenario 3. Technological challenges 4. Alternative approaches to connectivity 5. Conclusions CNLAB at KAIST CALAB at KAIST 2

Introduction 1. Introduction Wireless Local Area Networks(WLANs) • promising networking platform to extend network connectivity to wireless hotspots • several technological and deployment challenges remaining for ubiquitous infrastructure • ideal platform for networking in public places cellular data services • long-range, wide-area coverage • expensive licenses, high installation cost • not meet the connectivity for large data and performance-intensive multi-media applications CNLAB at KAIST 3

Introduction 1. Introduction Goal of this paper • highlight the challenges posed by the vision of a global hotspot infrastructure • Discuss the research problems that remain to realize • Authentication, security, coverage, management, location services, billing and interoperability CNLAB at KAIST 4

Benefits 2. An example scenario • Send email using Wi-Fi connection in San Francisco airport • Register with Wi-Fi network in New York • WLAN determines location and guide to meeting room • Connect to corporate network through a VPN using WLAN • use the GPS using CDMA 2000 • Access corporate email using hotel Wi-Fi network. Question • How easy is it for her to get connected when traveling from one hotspot to another? • Is there one single authentication entity at all places? • Is she able to get access from any location within the hotspot, or are there areas where there is not adequate coverage? CNLAB at KAIST 5

Technology 3. Technological challenges 3. 1 Authenticating to the Hotspot Provider Formal authentication mechanism • Enables users to identify themselves to the network 6 Research questions • Ease of Access • Mechanism • Startup Latency - SIM card: lost, malicious user • User Identity: existing identity • Third-Party Authenticators CNLAB at KAIST

Technology 3. Technological challenges 3. 2 Wireless-hop security need of the provisioning of wireless-hop security • not familiar with higher-layer security mechanisms • sensitive information need to exchange securely • to protect network against malicious users MAC Layer Approaches • Wired Equivalent Privacy (WEP) in Wireless LAN standard - disadvantage: not scalable to configure keys to many users encryption algorithms are vulnerable to attack • Port based network access control - more secure than WEP - disadvantage: lose validity after a short amount of time changing AP, need re-authentication CNLAB at KAIST 7

Technology 3. Technological challenges 3. 2 Wireless-hop security Network Layer Approaches • CHOICE network architecture - per-packet verification - access keys are issued and verified using a centralized Authorizer. Verifier entity - more scalable because of less state maintenance in the AP Security Challenges • Mutual Trust • Simplicity-Robustness Tradeoffs • Dynamic Key Management • Hardware Approaches • Denial-of-Service • Malicious Attacks CNLAB at KAIST 8

Technology 3. Technological challenges 3. 3 Radio Frequency Range Roaming mobile user • If RF coverage is not adequate, user can easily lose connection • For uninterrupted connection, hotspot operators increase the density of hotspot coverage Range extension Challenges • Power management • Wireless LAN Bridging • Hardware Approaches • Wireless MANs • Multi-hop Hotspots • Interoperability with Cellular Data Network CNLAB at KAIST 9

Technology 3. Technological challenges 3. 4 Network Performance and Qo. S Ability of hotspot administrators • handle dynamically varying, location-dependent user load • Guarantee a certain minimum level of Qo. S Install enough APs to handle the estimated load • Increase the infrastructure and maintenance cost • Limit the number of APs because of interfering channel CNLAB at KAIST 10

Technology 3. Technological challenges 3. 4 Network Performance and Qo. S Dynamic resource adaptation • accurate way of measuring load at each AP • guarantee a minimum available resources Challenges • measurement and modeling • monitoring • Effectively measure and monitor load at AP • Qo. S Enforcement • End-to-End Qo. S CNLAB at KAIST 11

Technology 3. Technological challenges 3. 5 Network Management Network capacity planning • As hotspot coverage grows, APs need to be installed at various parts of network 12 • APs can be installed after a site survey Challenges • Heterogeneity • AP State Management • Switched Wireless LANs CNLAB at KAIST

Technology 3. Technological challenges 3. 6 Location and Context-Awareness Ubiquitous availability of hotspot • make location and context-aware service more valuable 13 Challenges • Application scenarios • Location privacy and anonymity • Sensor fusion • Absolute Vs Relative location • Interpreting location CNLAB at KAIST

Technology 3. Technological challenges 3. 7 Pricing Model Current pricing model of Wi-Fi • Users are not compelled to buy Wi-Fi connectivity 14 Challenges • Payment model • Central billing entity - unified pricing mechanism( internet + hotspot charge ) • Third-party billing contracts • Usability - contract the task of infrastructure deployment, management, and support to third-party vendors. CNLAB at KAIST

Alternative 4. Alternative Approaches to Connectivity 4. 1 Multi-hop hotspots Multi-hop • A network where mobile nodes reach the AP over one or more hops • Increase the network diameter • Allow client out of range of AP to receive connectivity Multi-hop Challenge • Node Mobility • Channel Interference • Power Management • Multiple Network Access - one adapter & multi radio - one adapter & multiplex connection - multi adapter CNLAB at KAIST 15

Alternative 4. Alternative Approaches to Connectivity 4. 2 Interoperation with WAN Data Services Cellular network • Alternative Wi-Fi network • Need hardware & software support Challenge • Handoff mechanism • System( device & network support ) support for handoff • billing CNLAB at KAIST 16

Conclusion 4. Conclusions Highlight several technical and deployment-related challenges • Authentication, security, coverage, network management, billing, and interoperability For the end user • Provide a mechanism that is easy to use, economically attractive, and provide fast access For the hotspot network providers • Have a reliable and robust third-party authenticating entity • Establish peering agreements with other providers for seamless and various service For the premise and building owner • Establish business agreements with hotspot network providers CNLAB at KAIST 17

Any Question? CNLAB at KAIST 18