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An adaptive networking protocol for rapidly mobile environments Ph.D. Research Proposal Edwin A. Hernandez April 22th, 2002 Motivation Mobile-IP is the most widely used mobility solution in IPv4 and IPv6 networks. However, the performance for vehicles moving at high-speeds is questionable. Predictable trajectory and mobility, network originated handoff, and distributed registration can improve the performance of Mobile-IP without the use of costly micromobility protocols. Table of Contents • Introduction • Related Research • Performance of Micro- and Macro-Mobility protocols • RAMON: A proposal for network emulation. • Predictable mobility in wireless networks • Extensions for a predictable Mobile-IP Introduction – Concepts in Mobile Networks • 1. Forwarding Agent when a MH is foreign network • 2. Location Directory (LD), location information • 3. Address Translation Agent (ATA) Home network Stationary host Internet routing Foreign Network g ( fowarding address ) home address f (home address) forwarding address Introduction – Packet Forwarding Model Location Directory Home network LD Address Translation Agent Source Foreign Network Forwarding Agent f g Cache Internet routing MH f: Home Address g: Forwarding Address Forwarding Address Home Address Network-layer mobility is solved by registering in a centralized database of location, LD, which also solves problems of authentication, accounting, and authorization of mobile users in the network. However, network delays, time for authentication, and handoff render the packet-forwarding model unusable for fast moving hosts Related Research • Solutions to the problem of mobility – Macro-Mobility protocols • Mobile-IP • Hierarchical Mobile-IP (Hierarchical Foreign Agents) – Micro-Mobility protocols • Cellular-IP • HAWAII [Perk95], [Perk96], Solo[98] Mobile-IP HA MH CH Router Router •Mobile-IP follows the LD/FA model •Encapsulation is required when packets are forwarded •Mobile node acquires care-of-address thru DHCP. Src X Router Dest MH Proto ? FA payload Src HA Home Agent Encapsulated datagram Dest FA Proto Src 4 or 55 X Dest MH MH Triangular routing in Mobile-IP Foreign Agent Mobile Host Src X • Registration overhead of 1 sec. Dest MH Proto ? payload Proto ? payload Handoff in Mobile-IP MH FA HA Send Solicitacions Send Advertisements Update Agent List Handoff necessary Registration Request Forwarding Request Registration Reply Forwarding Reply New COA • Handoff overhead >= Registration Overhead • Handoff Impact = confuses TCP [Perk96a], [Cast98] Reducing Registration Overhead Hierarchical Foreign Agents Early reaction of the research community Internet FA1 HA Registration FA2 FA3 Registration FA4 FA5 MH FA6 MH FA7 MH An FA includes in its Agent Advertisement message a vector of care-of-addresses, which are the IP address of all the ancestors in the tree as well as its own. By the time the MH arrives to a new cell, it makes an advance registration to the HA, the FA, and the ancestors of the FA. • Reduces Registration Overhead • Requires many wired-nodes/costly During handoff of HFA During Handoff, the MH compares the new vector of care-of-addresses with the old one. Again, it chooses the lowest level address of the FA that appears in both-vectors and sends a Regional Registration Request, which is processed by the FA. There is no need to notify any higher-level FA about this handoff since those FA already point to the proper location to where to tunnel the packets for the MH Micro-mobility Protocols • 2-tier solution • Micro-mobility model used by Cellular-IP and HAWAII [Camb00, Ramj00] • Intra-domain handoff is handled by a signaling protocol while the interdomain handoff is taken care by the Mobile-IP protocol CH Network Home Domain Router HA FA root root home domain MH Foreign Domain Router foreign domain Movement between domains, HA is notified Movement within domain, HA not involved Movement within domain, HA not involved Cellular-IP Correspondant host Home Agent Mobile IP Internetworking R IP routing IP tunneling Cellular IP routing BS4 BS2 b BS1 a Mobile X BS3 Mobile X routing handoff Layer-2/3 routing and handoff management, use of Signal strength and telephony-like signaling for paging and handoff management. HAWAII: Handoff-Aware Wireless Access Internet Infrastructure (0): 1.1.1.1->B (3): 1.1.1.1->C A B 3 (0):*, 1.1.1.1 ->B (3):A,C, 1.1.1.1 -> B B, 1.1.1.1->C (6) : *, 1.1.1.1->C Router 0 C A 4 4 (0): 1.1.1.1->A (4): 1.1.1.1->B Router 2 1 A Router 1 B A C B C (0):*, 1.1.1.1 ->C (4):A,B, 1.1.1.1 -> C C, 1.1.1.1->A (5) : C, 1.1.1.1->CA Router 1 Router 0 B C 3 A B (0):*, Default ->A (2):*, 1.1.1.1 -> B A C 6 (0): 1.1.1.1 ->C (2): 1.1.1.1 ->A B C 7 Router 2 5 2 A (0): 1.1.1.1->B (1): 1.1.1.1->A Old BS 5 A B B (0): Default ->A (4): 1.1.1.1->B New BS (0):*, 1.1.1.1 ->B (5):*, 1.1.1.1 -> A Old BS A A B B 2 New BS 6 1 Mobile Host Mobile Host IP: 1.1.1.1 (a) MSF (Multiple Stream Forwarding) IP: 1.1.1.1 (b) SSF (Single Steam Forwarding) (0):*, Default ->A (1):*, 1.1.1.1 -> B A closer look to Micro-mobility • Signaling protocols based on telephony standards. • Avoid Mobile-IP for handoff • Costly implementation for a wide-spread area, e.g. train track, tied to speed. Requires the modification of intermediate routers and network infrastructure. • The packet loss can be described by rThoff, where r is the rate and Thoff represents the amount of time to reach the cross-over router from the MH. • Our research re-examined the performance of Macro- and Micro-mobility protocols in a simulation environment. Network Simulator (ns) plots network simulator (ns) tcl protocols ns objects 4G trace file results trace analysis awk, xgraph stats 802. 11a New Technologies (to develop) networks •The ns network simulator – Berkeley [Fall00] • tcl/c++ object oriented, 20 Mbytes of code, wired and wireless network protocols PERFORMANCE OF MACRO- AND MICROMOBILITY PROTOCOLS IN A RAPID MOBILE ENVIRONMENT • Two simulation scenarios were used: – Mobile-IP original Berkeley/CMU implementation – Columbia University micro-mobility suite • Results for Macro-mobility protocols were published in LCN 2001. – E. Hernandez and A. Helal, "Examining Mobile-IP Performance in Rapidly Mobile Environments: The Case of a Commuter Train," LCN 2001, Tampa, FL, Nov 14-16, 2001 – E. Hernandez and A. Helal “RAMON: a network emulation testbed”, submitted to Wireless Communications Journal, Wiley & Son’s. ns simulation scenarios C-host 0.2.0 W(0) 0.0.0 W(1) 0.1.0 10ms 20ms 30ms 100ms Mobile Host 1.0.1 (a) Real track BS(1) 1.0.0 BS(2) 2.0.0 BS(3) 3.0.0 (b) ns scenario BS(10) 10.0.0 Performance of Mobile-IP for TCP transmissions (FTP) 100% 90% 80% 50 40 250 m 500 m 30 750 m 20 1000 m Time transmitting Throughput (Kbytes/s) 60 70% 60% 50% 40% 30% 250 m 500 m 750 m 1000 m 20% 10% 0% 10 0 0 20 40 60 80 100 0 20 40 60 80 Speed (m/s) Speed (m/s) (a) Average throughput (b) Percentage of usable time (not in handoff) ns-2 simulation. [Hern01] Performance of Mobile-IP for UDP transmissions 50 40 250 m 500 m 30 750 m 20 1000 m Time transmitting Throughput (Kbytes/s) 60 100% 90% 80% 70% 60% 50% 40% 30% 250 m 500 m 750 m 1000 m 20% 10% 0% 10 0 0 20 40 60 80 100 0 20 40 60 80 100 Speed (m/s) Speed (m/s) (a) Average throughput (b) Percentage of usable time (not in handoff ) ns-2 simulation. [Hern01] Performance of TCP/FTP transmissions macro/micro-mobility 12 100% Cellular-IP 8 Mobile-IP 6 HFA 4 Hawaii 80% %Usable Kbytes/sec 10 Cellular-IP Mobile-IP 60% HFA 40% Hawaii 20% 2 0% 0 0 20 40 60 80 100 Speed (m/s) (a) Average Throughput 0 20 40 60 80 100 Speed (m/s) (b) Percentage of usable time ns-2 Columbia micro-mobility suite Performance of UDP transmissions with macro/micro mobility 60 100% Cellular-IP 40 Mobile-IP 30 HFA 20 Hawaii 80% % Usable Kbytes/sec 50 Cellular-IP Mobile-IP 60% HFA 40% Hawaii 20% 10 0 0% 0 20 40 60 80 100 Speed (m/s) (a) Average Throughput 0 20 40 60 80 Speed (m/s) (b) Percentage of usable time ns-2 Columbia micro-mobility suite 100 Problems with the simulations • Columbia uses the NOAH (non-adhoc agent) developed by Widmer [Wid00] as an extension for ns • The NOAH agent has a simplified version of propagation model. • The NOAH agent has a “improved” handoff mechanism and assumes GPS information – NOAH->getX() and NOAH->getY( ) methods – Mobile-IP with NOAH outperforms its predecessor. • It’s hard coded the bandwidth at 2Mb/s and difficult to change in the simulator. • Simulator code is more than 20 Mbytes, why not implement it directly on a testbed? RAMON : A network emulation approach • Criticism of network simulation approaches [Paw02] • Attenuators used to emulate velocity and handoff • Real implementation and code-extensions made to real mobility agents • Network emulation language to facilitate, academic and network-engineering work. • ns scripts can be parsed and emulated with minor modifications. • Applications can be tested in rapid mobility conditions RAMON: The architecture Path loss attenuation and data rates with 802.11b access points distance (m) 101 201 301 401 12 501 distance (m) 0 601 -20 PL(d) 100mW -30 Data rate 8 6 -60 4 -70 -80 100 200 300 400 500 600 700 -20 -40 -50 0 10 PL(d) 1mW Path Loss (dBm) PL (dBm) -10 1 Data Rate (Mb/s) 0 -40 -60 PL(d) (5mW) PL(d) (30mW) PL(d) 100 mW -80 2 -90 -100 -100 0 -120 (a) Path loss and data rate for Cisco AP-350 (b) Path loss equations at different transmission power levels (n=2.5) • It’s necessary two provide actual bandwidth to accurately estimate and reflect the effects of speed and handoff on network cards 800 Attenuation Control with the parallel port 74LS374 Attenuator 0 7 LD 74LS374 7 D0 D1 D2 D3 D4 D5 D6 Attenuator 1 LD 74LS374 7 Attenuator 2 D7 LD 74HC4051 SEL Autofeed S0 0 LDi IN 1 Line 14 LPT1 S1 74LS374 2 SEL 74HC4051 AB 2 2 LD Pseudo Code WriteLPT1(0xxx xxABb); // Select Attenuator <AB> address WriteLPT1(1xxx xxxxb); // Write data to the attenuator Emulation of speed Path Loss Equation: PLrecv Ptx P(d o ) 10n log( d ) do Scenario Attenuator 0 Attenuator 1 Attenuator 2 No connectivity -127 dB -127 dB -127dB One cell 0 dB <set < -80 dB -127 dB -127dB Two overlapped cells 0 dB < set < -80 dB 0 dB < set < 80 dB -127 dB Three overlapped cells 0 dB < set < -80 dB 0 dB < set < 80 dB 0 dB < set < 80 dB RAMON emulation language ns script Emulation script Description $BS X_ $BS Y_ $BS name X= $BS name Y= Sets the coordinates of the Base-station set BS [$ns node IP] $BS name IP= Sets an IP Address for the base-station set power 0.289 $BS name power=xxx The power level in mW in the access-point Set HA… /FA… $HA name IP $FA name IP Sets the HA/FA at an IP address set mobile-ip 1 $protocol=”MIP“ The protocol being used set wiredNode [$ns node $IP] $WiredNode name IP1 IP2 IP3 Creates a Wired Node with three interfaces. $ns duplex-link $node1 $node2 $bw $latency DropTail $Link IP1 IP2 bw latency Creates a Link between two interfaces using certain bandwidth and latency values $ns at $time [$MH etdest x y speed] $MH time x y speed Sets the destination position and speed of mobile host. Acceleration = 0. $ns at $time start - Starts after it’s called $ns at $time end $end time End of the emulation $set opt(prop) Propagation/TwoRayGround $Propagation=”TwoRayGround” |”PathLoss”|any other. Sets the propagation model being used. N/A $granularity X Updates attenuation and speed every X ms Convert an ns script into emulation code Platform commands $route – add … ns.tcl Create wired nodes Routing/Emulation tables Load Mobility agent, Configure agents Load mobility Patter of node Goal : Process a modified version of an ns script and generate the emulation environment $cnistnet –a …. $fa @ IP… $ifconfig –eth0:1.. $start attenuators $load pattern Go emulation! Sample Emulation Script $WiredNode node1 192.168.1.1 192.168.2.1 192.168.3.1 $WiredNode node2 192.168.2.2 192.168.4.1 192.168.5.1 $Link 192.168.2.2 192.168.2.1 10Mb 20ms $Link 192.168.1.1 128.227.127.11 10Mb 1ms …. $BS node7 X=250 Y=250 power=20dBm IP=192.168.7.1 $BS node8 X=750 Y=250 power=20dBm IP=192.168.8.1 $BS node9 X=1250 Y=250 power=20dBm IP=192.168.9.1 $BS node10 X=1750 Y=250 power=20dBm IP=192.168.10.1 $BS node11 X=2250 Y=250 power=20dBm IP=192.168.11.1 … $MH 0 1000 250 20m/s $start 10s $end-time 1500s $Propagation=”PathLoss” $Protocol “MIP” Emulation Code • • • • • • • • • • • Emulation(MH, granularity) initializeResources( ) DetermineRoutes(route[][], time_end[], trajectory(MH)); while timer() > end_simulation do if timer>=timer_end[k] then k++ createRoute(route[k][1..3], time_end[k]); expireRoute(route[k-1][1..3]) emulateMovement(granularity, MH ) return NistNET emulator for wired networks • Wired network emulation required for academic and network engineering of rapidly mobile networks with may service providers and heterogeneous networks. Example Architecture to emulate CH Link(i,j) { Bandwidth, latency, error } 2 4 7 MH 1 3 5 8 6 9 10 11 Emulation process t=0 t=2(d+ )/v default gw 1 7-4-8 8-4-2-5-9 7-4-2-5-9 default gw 1 7-4-8 7-4-2-5-9 8-4-2-5-9 7 8 9 7 9 MH @ v m/s MH @ v m/s (a) 10 8 (b) t=4(d+ )/v t=6(d+ )/v default gw 1 8-4-2-5-9 9-5-2-1-3-6-10 8-5-2-1-3-6-10 default gw 1 9-5-2-1-3-6-10 9-5-2-1-3-6-11 8 9 MH @ v m/s (c) 10 11 MH @ v m/s (d) 9 Implementation of RAMON antennas Agents Access Points Programmable Attenuators Controller for attenuator Attenuators Foundations for a predictive mobile environment Mobile-IP fails when: Tdwell Thandoff T forward Tregistration In the mobile environment, We can define a mobile host as: MH k IPH , IPC , P, SNR, G 0 1 2 3 4 0 1 2 IP@home, IP@care, P received, SNR signal to noise ratio, and G where G x, y, v, a 3 4 5 is a vector of position, speed, and acceleration, while a Base Station, 6 7 BS ij G, MH care , MH prev , MH next MHk BSi,j 5 6 7 Simple representation of geographical information 0 0 0 0 0 Prxy ( MH ) 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 0 0 0 1 1 1 0 0 1 1 1 0 0 0 1 0 0 0 0 0 0 1 2 3 4 5 6 7 0 1 2 BSi,j 3 r1 r2 4 5 6 7 Rough mapping of an 8x8 grid of geographical information to a matrix of probability of location. Geographical information thru: • GPS – not suitable for most PDA’s with low-power • Indirect measures Signal Strength, Inter-Access Point communication, etc Uncertain position given P received rssi = -40 dB @ t = 1 BSi,j rssi = -20 dB @ t = 2 rssi = -20 dB @ t = 3 rssi = -40 dB @ t = 4 7 2 3 r2 r1 6 4 5 1 0 By using Inter Foreign Agent or Inter Base-station messages BS.db GIS.db PLossModel() = Location <x,y> Predictable Mobility With the Location information obtained : • Trajectory predictors using mobility models and/or neural networks • Comparison with other predictable models • Reviewing mechanisms. – Kalman Filters – Neural Networks – Fuzzy Logic • Matlab simulation of the mechanism selected isn in progresss. • Implementation of the protocol in RAMON Extensions for Mobile-IP query/update query/update Home Agent (initial implementation) Location Registry Database Multicast Extension query/update • Inter-agent protocols IAP FA Context Information IAP FA IAP Extensios for predictable mobility • Network initiated handoff • Rely in mobile-IP for slow moving vehicles. IAP FA IAP FA • Extensions for a hierarchical-predictive registration. Predictable Home Agent • Inter-layer Communication (State Manager) / Chinta’s work Research timeline Task Expected Completion Date Current Status RAMON testbed February – April 31st, 2002 Performance of micro- and macro- mobility protocols on testbed Review of predictable algorithms and simulation for mobile protocol Session and Context Transfer for TCP Integration of mobile-ip and Predictable extensions Windows XP/Pocket PC implementation Performance Testing of extensions for mobile-IP Dissertation Preparation Dissertation Defense April 20th to April 31st, 2002 - Some hardware needs to be purchased. - Set up parser for simulation code into testbed scripts. - Ongoing investigation of Mobile-IP platforms and network emulation. - pending – testbed required. February – May 2002 - Already started matlab simulations . February – May 2002 May – June 2002 - Madhav Chinta’s thesis. TCP level implementation. - ongoing June 2002 - ongoing June 15st to June 31th, 2002 - pending Spring – Summer 2002 Summer 2002 - ongoing TBD completed List of References [Camb00] A. T. Campbell, Gomez, J., Kim, S., Turanyi, Z., Wan, C-Y. and A, Valko "Design, Implementation and Evaluation of Cellular IP", IEEE Personal Communications, Special Issue on IP-based Mobile Telecommunications Networks, Vol. 7, No. 4, pp. 42-49, August 2000. [Cast98] C. Castelluccia. “A Hierarchical Mobile Ipv6 proposal”, Technical Report INRIA, France, November 1998 [Fall00] K. Fall, K. Varadhan, editors. NS notes and documentation. The VINT project, LBL, February 2000. http://www.isi.edu/nsnam/ns/ [Hern01] E. Hernandez and A. Helal, "Examining Mobile-IP Performance in Rapidly Mobile Environments: The Case of a Commuter Train," Accepted to LCN 2001 in Tampa, FL, Nov 14-16, 2001 [Perk95] C. E. Perkins, K. Luo “Using DHCP with computers that move”, Wireless Networks 1(1995) 341-353. [Perk96a] C. Perkins, IP mobility support, RFC 2002, IBM, October 1996 Perk96b] C. Perkins, Mobile-IP local registration with hierarchical foreign agents, Internet Draft, Internet Engineering Task Force (February 1996 [Ramj00] R. Ramjee, T. La Porta, S. Thuel, K. Varadhan, L Salgarelli, IP micro-mobility support using HAWAII , Internet draft submission , Jul 2000. [Solo98] J. Solomon. Mobile-IP. Prentice Hall, New Jersey, 1998