ARPA Mobile Information Systems Applications Workshop December 7-8, Mobile Networking

Transcription

1 ARPA Mobile Information Systems Applications Workshop December 7-8, 1995 Mobile Networking Randy H. Katz CS Division EECS Department University of California, Berkeley 1

2 Mobile Networking Middleware Reliable Transport Radio Channel Mobile Applications Mobile Applications Support Mobile End-to-End TCP Networking IP Mobile Networking Wireless Communications Nodes Sophisticated network mgmt and routing algorithms suitable for the dynamic, multi-hop, wireless networking environment of the tactical battlefield Mobility Services Subnetwork Control Link Control Media Access 2

3 Media Access Cluster-Based CDMA/PRMA (UCLA) Packet reservation techniques for slots Multiple conversations per slot through code division Floor Acquistion Multiple Access (UCSC) Combines features of Carrier Sense Multiple Access (carrier sensing) and Multiple Access Collision Avoidance (collision avoidance dialog) schemes Achieves higher thruput than MACA by permitting bursts for each successive RTS/CTS handshake (i.e., floor acquisition ) Sufficient conditions for completely avoiding collisions 3

4 Link Control Link Establishment Code and slot assignment to minimize interference (KU, UCLA) Power control Adaptive Link Performance Bandwidth vs. Reliability Link level error correction and retransmission Power control Same codes Different time slot Pwr Cntrl Support for upper layer QoS requirements based on lower layer SIR constraints Orthogonal codes Same time slot 4

5 Subnetwork Control & Routing Topology Creation/Reconfiguration Hierarchical/Cluster-based Schemes (UCLA) Rapidly Deployable Radio Network (KU) Reliable/survivable network topology (Stevens) Routing Multihop Routing (UCLA, UCSC) Mobile IP (UCB, Others) Switch Mobility (KU, Stevens) QoS Driven Path Assignment (Stevens, UCLA, UCSC) Subnet Support for Multicast (Stevens, UCB, UCSC) Subnet Support of VCs with QoS Negotiation (Stevens, UCLA) GPS Integration with Routing (KU, UCSC) Wireline-Wireless ATM Integration (KU, Stevens) 5

6 Topology Creation Hierarchical/Clustering Algorithms (UCLA) Distributed Clustering Algorithm Time Division Slotting Slot Reservation VCs for R/T; DGs for data Code Separation per cluster Multihop Route subject to QoS Constraints 6

7 Topology Creation Dynamic Topology Reconfiguration (UCLA) Cluster merge/split under mobility VC reconfiguration in presence of mobility» Fast Reservation Scheme New Path Old Path R/T packets follow shortest path Rate adjustment based on advertised QoS First packet reserves slot on path First packet competes for slot on new path May be dropped if no path Low priority voice/video components dropped during switchover Reservation released if slot unused 7

8 Topology Creation RDRN Configuration (KU) Low B/W Broadcast Orderwire for location, link quality, mgmt info GPS High B/W Pt-to-Pt Links Beamforming Antennas GPS Infrastructure Node Medium Speed Single Infrastructure Node Hop Wireless ATM OC-3 ATM Prototype Edge Node Omni and Beamforming Antennas Prototype User Node 8

9 Multi-hop Routing Routing Algorithms (UCSC) Link Vector: New routing algorithms based on distribution of link information, used to reach destinations, to neighbors thru preferred paths Path-Finding: New loop-free distributed shortest-path algorithm utilizing length and second-to-last hop of shortest path Yield better behavior than flooding and Distributed Bellman-Ford, especially in presence of link or node failure Multiple successors from any node to any successor; Choice of route can reduce congestion Integration of GPS information in routing algorithms 9

10 Mobile Routing Mobile IP (IETF + Many Groups) Return CH Forw FA Packet HA Home Network Location Updates (c/o addr) Schemes to reduce dog leg routes, and location updates: Caching MH location at CH Dynamic source routing / CH directly tunnels to MH Local multicast groups Hierarchical foreign agents Roaming Network MH Agent Discovery & Registration Advertisement Solicitation 10

11 Mobility Services: Handoff Multicast-based Low Latency Handoff (UCB) Use terminal tracking to assist in HOs for R/T streams Video Server Multicast Group Base Station Base Station Multicast packets to adjacent base stations to smooth hand-offs 11

12 Mobility Services: Handoff Handoff between wireless subnets for connectivity; Load balancing/different traffic across subnets (UCB) Base Station Foreign Agent IP 1 IP 2 Base Station Foreign Agent Gateway Internet Gateway Corresponding Host Vertical Handoff IP address per NI 12

13 Multicast Routing DBS Support for Secure Multicast (Hughes & UCB) High bandwidth broadcast downlink Advertises changes in subscription groups Low bandwidth uplink; Authenticated exchange of multicast addresses and encryption keys MG 1 MG 2 13

14 Mobility Services: Tracking Virtual Network Configuration Algorithm (KU) Mobile tracking» Track direction, velocity, bandwidth, # connections, past history, etc.» Use to predict future network state Use to control antenna beamforming, topology changes, switch/routing tables, resource allocation, etc.» Predict forward/roll back if in error» Allows fast reconfiguration Orderwire virtual messages estimate future behavior Accurate, synchronized timing through GPS crucial 14

15 Given Common Themes Quality of Service requirements imposed from above Signal-to-Interference Ratio constraints from below Exploit local knowledge Cluster/Hierarchical Schemes (UCLA), LV Algorithm (UCSC) Mobile Tracking (KU, UCB) Find best routes subject to QoS constraints Multi-hop (UCLA), Multi-path (UCSC), Virtual Path (Stevens) Best overlay (UCB) Retaining connectivity while moving Beam steering (KU) Changing route (UCLA, UCSC) Changing overlay (UCB) Reliable/Survivable Topology (Stevens) 15