1. 0 Research Challenges in Mobile Networking and Computing Thomas F. La Porta Professor, Department of Computer Science and Engineering Penn State University Outline Overview of Mobile Networking and Computing Mature Research – Micro-mobility – System interworking Open Research Topics – Security proposal Summary

2. 1 Mobile Internet - Ubiquitous Communications and Computing Wireless access to networks will soon be the most popular method Today: 850M phone lines, 700M wireless subscribers Wireless growth far exceeds wired growth Internet is driving network growth Internet users still doubling yearly Ubiquitous wireless data has stalled… low data rates limited terminals limited applications …Mobile computing has not lap tops are everywhere dial-up service is pervasive è Hindered by low performance, poor connectivity, and inconvenience Global Access Lines (billion) 32103210 Wireless Cable Wireline 1958 1978 2005

3. 2 Mobile Communications Today: Tale of 2 Networks Cellular Telecommunications Network Network tailored for voice – very low bandwidth Devices not suitable for Internet and computing applications è Despite high penetration & coverage, Internet access has fizzled The Internet – Wireless Enterprise Networks Network tailored for best-effort data traffic – high bandwidth, no controls Supports general computing and data networking applications è Gaining high density in hot-spots, but no ubiquitous coverage Radio Wireless Controllers Telephone Network Internet Wireless Gateways Radio Edge Router Telephone Network Internet Access Router

4. 3 Evolution to Multiservice networks Core Internet Backbone Authentication Presence Location Aggregation Router Access Router 3G Cellular Networks Radio Controller Access Router Urban Networks Home Networks Enterprise Networks 4G Radios Ad Hoc Networks 4G Air Interface 4G Radios DSL/Cable High Speed Internet Access Broadband Distribution Networks High Speed Pico Cells 802.11++ Local Mobility Packet Voice High Data Rates Outdoor Areas High Mobility Allow People to network Self Configuring End-to-end Internet – common mobility management and control – common transport infrastructure – common services infrastructure è Unifies various technologies (wireless, wireline, mobility)

5. 4 Examples of Individual Multiservice Networks Wireless Networks 1980’s – voice services 1990’s – voice services with very limited data capabilities (e.g., short messaging) 2000’s – 3G multimedia networks (voice, data, multimedia) Internet Original use – best effort data (email, remote login, file transfers) 1990s – some multimedia (video and audio streaming, conferencing) 2000’s – merging of data, voice, and multimedia (Internet telephony in enterprises) Next trend (already ongoing): merging individual networks Impacts: – transport – control protocols – services infrastructure – management – security

6. 5 Merging of Networks Many challenges due to diverse applications, legacy systems, and philosophies Voice (aka Public Switched Telephone Network) and Data (aka The Internet) Public and Private (corporate networks) Interworking is a big problem – service definitions, protocols, profiles, … End result: Telephone network will get dumber, the Internet will get smarter

7. 6 Where are we? Seamless high-speed ubiquitous network access new access technologies – many already exist mobility between networks – active research area ( ) Internetworking drive towards common control paradigm – controversial ( ) interworking between networks – islands exist ( ) performance – new demands on network controllers Security eCommerce, enterprise data, distributed computing – no one feels safe authorization and accounting – bringing order to chaos Intelligence and Applications distribution between network and end devices – solutions have been vertical

8. 7 Where are we? Seamless high-speed ubiquitous network access new access technologies mobility between networks – real-time mobility – Handoffs – real-time location – Paging Internetworking Security Intelligence and Applications

9. 8 Current Internet-Based Mobile Packet Networks: Mobile IP Handoffs always managed by Home Agent – high update overhead – slow handoffs 3G UMTS Network structure is similar – uses specially defined (non-Internet) protocols for mobility Intranet MD Host Regular routing IP Tunneling Internet Radio Access Networks Foreign Agent Foreign Agent Home Agent Permanent IP Address Temporary IP Address

10. 9 Real-Time Mobility: Domain-based Mobility Distributed control: Enhanced reliability, better scaling Localized mobility management: Lower overhead, fast handoffs Based on IP protocols: Independent of access network è Mobility across access networks Domain Router RR RRRR Domain Router RR RRRR Local mobility Internet MD

11. 10 Real-Time Mobility: HAWAII for handoffs Distributed control: Enhanced reliability – recovery of lost state via Internet routing protocols Localized mobility management: Lower overhead, fast handoffs – updates only reach routers affected by a movement Minimized or Eliminated Tunneling: efficient routing, easy QoS – dynamic, public address assignment to mobile devices è Compatible with Mobile IP Domain Router RRRR Domain Router RRRR Local mobility Mobile IP Internet MD RRRR

12. 11 HAWAII Overhead Domain Router/HA Router 1... BS1 BS-20... BS1 BS20 T BL BL M DB DB 16 2      IP  16YT R BDBD L RBL T BL BL H B DDB M DB DB 16 2 2           Hawaii M-IP Router 7

13. 12 HAWAII Handoff Delay: Packet Loss Audio (160B/20msec)

14. 13 Real-Time Location: IP Paging Motivation – dormant mode increases battery life considerably – mobile device must be located (quickly) to deliver data – currently each network type has unique paging protocols Challenges – limit overhead (messages) while maintaining low latency – do not impact fast-path packet forwarding – devise scaleable solution in terms of network size and administrative domains – support various paging algorithms Basic Solution – compatible with and leveraging IP protocols – distributed control for scale and scope Serving Router/Switch Home Router/Switch Host RRR Network MD Determined by address Determined by Registration Determined by Paging

15. 14 Unified Paging Internet Home Agent Foreign Agent Foreign Agent Foreign Agent R R R Domain Paging Area Mobile IP Paging Area 3 Options: Home Agent Paging – Home agent buffers packets and initiates page to all Foreign Agents – Can be controlled by corporate network – Does not scale Foreign Agent Paging – Last active Foreign agent buffers packets and initiate paging – Distributes load Domain Paging – Fully distributed, very scaleable and reliable Uniform mobility management – wireless LANs, outdoor Old FA initiates page HA initiates page Any router initiates page

16. 15 IP Paging: Domain Paging Basic Procedures – dormant MH does not send updates unless crossing Paging Area – packets sent to last known domain – any router in old path to Mobile Host may initiate paging Characteristics – more complex: changes to routers in access network – excellent scaling: load distributed among all routers – excellent scoping: only routers in a paging area need topology information – excellent reliability: failed routers are routed around (OSPF) Internet Any router initiates paging IP Paging Area Domain Router R R R R R R Domain Router R R R R R R

17. 16 IP Paging: Latency Results Latency (from Stanford University Local Area traces) – Foreign Agent and Domain Paging scale best: distributed load – Domain paging slightly more scaleable (~10%): dynamic load balancing Messaging Overhead – Domain Paging has lowest overhead: no paging related updates to Home Agent

18. 17 Where are we? Seamless high-speed ubiquitous network access Internetworking drive towards common control paradigm – Internet Control interworking between networks – support for legacy systems (and stubborn operators!) performance – efficiency Security Intelligence and Applications

19. 18 Internet Control and Interworking: Unified Mobility Manager Integrate 3 key functions of HLR & IP (VoIP) servers – mobility management – security – profile management Support multiple interfaces – Wireless: ANSI 41, GSM / UMTS MAP – Internet: VoIP (SIP, H.323), AAA (RADIUS) Current Integrate HLR/VoIP server functions MAP / SS7 Integrated User Profile Database Security manager Protocol Gateways User location manager Cellular Internet VoIP / IP AAA / IP Internet (VoIP) VoIP server IP security server Cellular HLR User/mobile location management Security control (authentication center, IP security server) Service profile DB management Cellular ANSI41 / SS7 Provide Home Location Register and Internet functionality

20. 19 Unified Mobility Manager: Architecture Core servers -Common functions across protocols -Interface via abstraction of basic services -Multiple server instances on a cluster of processors for system scalability -Interworking function between protocols: O(n) versus O(n 2 ) complexity Protocol gateways -Perform protocol specific controls -Facilitate new protocol introduction Integrated user profile DB -Common database for a ‘user’ CDMA 2000 VoIP Servers GSM/UMTS Wireless Data Integrated user profile PG Core Operations Core Servers PG

21. 20 UMM – Location Management Performance 2 Basic Scenarios Considered: UMTS Network with HLR or UMM 2 call scenarios – goal: calls travel over IP network – call from PSTN to UMTS phone (PSTN to cellular) – call from SIP phone to UMTS phone (Internet to cellular) UMM Internet Serving Switch BS MGW GW Switch PSTN Serving Switch BS PSTN call SIP Call GW Switch SIP PSTN Serving Switch BS MGW HLR Internet HLR & UMM are the same SIP-UMM uses packet for transport efficient HLR/ UMM SIP-HLR uses PSTN for transport inefficient UMM Internet Serving Switch BS SIP-UMM (SIP e2e) most efficient

22. 21 UMM Analytical Results Migration to packet – short term: performance degradation from circuit/packet translation – long term: packet end-to-end improves performance

23. 22 Research Topics: Intelligence For Network Transport Balance between simple networks and functional networks Ad Hoc Networks – self-configuration – very dynamic routing – Challenges: security, performance, relay networks to enhance cellular telecom Sensor Networks – power-aware component to most functions (routing, etc.) – nodes participate in processing information – Challenges: placement, distribution of functions Traditional Networks – multiclass admission control & charging algorithms – IP Services platforms (firewalls, web redirection, …) – Challenges: heterogeneous networks, network architecture Heterogeneous Networks – real-time mobility between networks – Challenge: vastly different network characteristics

24. 23 Research Topics: Intelligence for Services Support for creativity, rapid deployment, and wide accessibility Network architectures – separation of transport and service control – re-use across network types – Challenges: scalability, performance, reliability Protocols – interworking across systems – legacy systems – Challenges: correct semantics, functionality mapping, software Heterogeneous networks – access from different networks – access via different protocols – Challenges: security, flexibility, performance Transport Services

25. 24 Research Topics: Security Performance/Security Tradeoff Traditional Wireless 3G data services require network-based enhancements Challenges – limiting performance impact, or improving performance Ad hoc wireless, sensor networks existing solutions are not scalable Challenges – trade-offs of security and performance General end-to-end security solutions, including network, devices, OS, …

26. 25 Performance Focused Security Goal: Allow network-based performance enhancements in a secure environment Specific Problem: Data performance in wireless networks is poor – network-based solutions have been proposed for 3G – caching has been proposed for ad hoc and relay networks – proposed solutions contradict security models for mobile VPNs Sketch of solution – allow at least one intermediate “router”, positioned at the edge of the network, to view and process a portion of a secure packet – trade-off level of security for performance Benefits – higher performance data services – access to network-based value added services with limited security trade-off

27. 26 Security Solution for 3G: Mobile Multi-layered IPSec Define multiple zones in a packet (as in ML-IPsec by Zhang and Singh) – each zone has an associated security association (keys, etc.) – each zone may be terminated in one or more places inside the network Research: Initialization, Mobility, Performance – distribution of keys and initialization – maintenance of security during mobility – performance impact – implementation issues Client Wireless Router NetworkFirewallHost Corporate Network End-to-end encryption for payload Concatenated encryption for control information } Example

28. 27 Ubiquitous Mobile Computing - Summary The potential still remains… …Hard work required - – networking: end-to-end systems issues with access and core – intelligence: distribution between device and network (dynamic & flexible) – applications and support services: retain generality – new network architectures … with Imagination - – new ways to use mobile capabilities – perhaps extension of wireline network paradigms is wrong!!!