Year, pier University Nikos Migas PhD student 2 Supervisors: School of Computing, Na MARIAN

Transcription

1 MARIAN Mobile Agents for Routing In Ad-hoc Networks Nikos Migas PhD student 2 nd Year, School of Computing, Napier University n.migas@napier.ac.uk Supervisors: W.Buchanan, K.McArtney

2 Introduction MARIAN is an on-demand, multi-agent, metric-driven routing protocol in ad-hoc networks. It utilises both static and mobile agents to determine optimal routes and to actually route the data. Each mobile device is equipped with a: Proxy agent. responsible for forwarding network traffic. Java-based, multithreaded allowing multiple connections. Benchmarking multi-agent Software System (BASS). Executing standard performance tests (memory, CPU, processing capabilities, etc.). Monitoring the utilisation of the device. Producing a metric of the performance of the devices in real-time. The purpose of this presentation is to introduce this novel research area and to present the novel findings concerning: Proxy capabilities of resource-constrained devices. The effect the OS and the JVM may have in performance. The resources consumption rates while routing, in terms of: Battery discharge rate, CPU utilisation, heap memory usage, and temperature.

3 Research Hypothesis Is it possible to create an automatically configuring system which will route data through ad-hoc networks in an optimal way? For this we propose: A framework using static and mobile agents that can be used for routing, network discovery, and automatic network reconfiguration in ad-hoc networks, in an efficient, effective, and secure way. Virtual Internet domain wireless domain

4 Possible benefits and outcomes (1) Maximize network performance Mobile agents could filter huge amounts of data locally to the devices, generated by BASS. Thus, benefit from local interactions. Determination of low and high bandwidth routes. Low bandwidth routes will be used for asynchronous network traffic ( s, text), while high bandwidth routes for synchronous network traffic (real-time audio, video). Scalability MAs are inherently distributed, thus there is a scope for a totally distributed system. The workload will be distributed evenly:» High performance devices will be responsible for complex calculations and tasks.» Low performance devices will be used as an alternative when high performance devices are unavailable or busy. Dynamic Mobile agents are reactive, that is, they sense the environment, and react in changes of the environment. Reliable end-to-end communications Mobile agents will migrate to other network nodes and communicate locally. Mobile agents can wait until the network is available, and migrate then.

5 Possible benefits and outcomes (2) QoS guarantees The transmitting device could request an estimate of the available bandwidth through a certain route. Security Only authenticated agents will participate in the routing process. A guard static agent will protect device s resources from potential malicious agents. Balance between security and performance. Reconfigurability Mobile agents can be easily dispatched to install updates in the routing protocol. Energy efficient Devices with low performance characteristics, or low battery life will not be overutilised by the routing protocol.» Busy devices will not participate in routing, as long as other devices can do the same job.» If battery life of a device is low, the routing protocol will consider that device as a weak link.

6 Background Wireless networks and the usage of mobile devices are becoming increasingly popular, especially in creating ad-hoc networks The great benefit of wireless networks is the ability of users to communicate, cooperate, and access the networked services in an anytime and anywhere fashion. Wireless networks can be grouped into two categories: Infrastructured networks Fixed and wired gateways, with access points A mobile unit connects to, and communicates with, the nearest access point that is within its communication radius. Infrastructure-less networks (typically known as ad-hoc networks) A collection of geographically distributed mobile nodes that communicate with one another over a wireless medium without the need of fixed networking equipment, such as routers and switches. Mobile nodes could act as gateways to other networks.

7 Routing in Ad-hoc networks Routing is the most important function in ad-hoc networks, however a challenging issue: Mobility e.g. A route that is considered as good now, may become unavailable or not optimal some time later Routing requires a lot of processing power Mobile nodes running on batteries may not be able to cope Multimedia traffic? Asynchronous A traffic? B Secure traffic?

8 Applications of Ad-hoc networks Military Battlefield Terrorism & Rescue Operations Hospitals Evacuation of a building on fire Retrieve patient s information from hospital s database while in surgery Conference meetings Share information quickly Schedule meetings Networking while on the road Inter-vehicle communication

9 Mobile Agents (1) Proposed as a promising solution for distributed computing over open and heterogeneous networks. Proposed to overcome certain limitations of traditionally designed distributed systems such as client-server. A mobile agent can be defined as a software program that can suspend its execution on a host computer, transfer itself to another agentenabled host on the network, and resume its execution on the new host. The key features of mobile agents are: Mobility; networks awareness; communication; intelligence; reactivity; autonomous; goal-oriented; temporarily continuous; learning; flexible; and character A mobile agent consists of its code and state, which carries with it during the self-initiated migration

10 Mobile agents v. client/server? Server Agent migrates to the server Agent Agent communicates with the server, on the server Mobile agents in a client/ server architecture Network Response message Get message Traditional agent in a client/ server architecture Server Client

11 Mobile Agents Systems (MAS) Mobile agent systems provide an environment in which mobile agents can exist and offer standardized services to agents docking on Services include: communication; migration; security; creation and termination of agents Many mobile agent systems have been developed from academic and industrial background. According to a comprehensive list on MAS (Fritz Hohl, Stuttgart): There exist approximately 70 mobile agents systems (commercial & educational). Most MAS are implemented in Java due to platform independence. Some well-know are: MOLE, Telescript, Aglets Workbench, ffmain, D Agents, Tracy, and Grasshopper. However, only few support mobile devices: Grasshopper ME (PocketPC)» The most comprehensive MAS for PDAs.» Well-documented. AgentSpace (PocketPC)» Insufficient documentation. Tracy 2 (PocketPC)» Under development. No real support for other Operating Systems (OSs): Familiar Linux. Embedded Linux.

12 Mobile agent applications Mobile agent paradigm has been proposed for a number of applications: Internet-wide collaboration systems. Network management. Monitoring systems. Information retrieval. Intrusion detection systems. E-commerce. A new potential application that mobile agents are ideal is wireless networks Mobile agents support asynchronous communication, and flexible query processing. User tasks can be delegated to mobile agents, and then a mobile client can disconnect. Can reduce network traffic under some certain circumstances. Maintain load balancing.

13 JVM support for handhelds Most mobile agent systems are developed in Java: Platform independence. Portability of code, which is the nature of mobile agents. Therefore a JVM is necessary to provide the: Execution environment for MAS. Familiar Linux Pocket PC 2003 Pocket PC 2002 Grasshopper ME/SE J9 JRE 1.3 Grasshopper ME J9 CrEme Jeode Grasshopper ME J9 CrEme IBM J9, Insignia Jeode, NSIcom CrEme, and Blackdown JRE 1.3 are Sun certified JVMs. Jeode is only available for PocketPC J9 does not officially support Familiar Linux. JRE 1.3 is the implementation of the full Java 1.3 version. The rest are J2ME compatible.

14 Resource-constrained devices (PDAs): Limited bandwidth Average when operating in a client-server mode. Approximately 4-5Mbits/s. Dramatically reduced when acting as a proxy. Ranges between 3-70Kbits/s. Workstations and laptops achieve up to 10 times more. Power consumption (Familiar Linux, ipaq). When IDLE: Battery lasts 5 hours and 40 minutes. When IDLE, wireless on: Battery lasts 3 hours and 20 minutes. When routing, wireless on: Battery lasts 2 hours. Computational deficiency Small-scale processing power, low memory capacity, and slow internal busses may be just a few of the reasons that prohibit the execution of complex calculations. Complex computational tasks such as the 4D bubble sort of 30,000 random integers: PDA requires 15 times more time than a laptop. PDA requires 40 times more time than a workstation.

15 Routing software vs. Proxy Routing software: It requires complex and power intensive calculations. It takes into account low layers of the OSI model. Resource-constrained devices may not be able to efficiently execute them. It requires high implementation effort. Proxy It bases its functionality on simple TPC/IP socket implementation. They can be light-weighted. They can be efficiently executed on resource-constrained devices. Proxies can be designed as Java-based stationary agents.

16 Agent diagram Bandwidth and Resources monitoring Temperature agent 2 Battery agent 5 3 CPU utilisation agent 4 Heap memory usage agent Resources monitoring agent 6 Proxy agent 7 TTCP transmitter agent 9 8 TTCP receiver agent 10 9 Bandwidth calculation agent 10 Data gathering agent 11 Librarian agent 11 File output Benchmarking bandwidth and Resource Consumptions multi-agent Software System (RCASS) is designed with purpose to benchmark bandwidth proxy-pdas in adhoc networks. It also has the capability of monitoring resources consumption of the PDA in terms of: Battery discharge rate, CPU utilisation, heap memory usage, and temperature.

17 Overview of the Bandwidth and Resources monitoring functionality TTCP receiver listens on a fixed port Proxy agents listens on a fixed port 1000, and forwards incoming traffic to the receiver at port TTCP transmitter sends network traffic to the proxy on port Once the proxy establishes a connection with the transmitter and receiver: It forwards incoming network traffic to the receiver. It creates the resource monitoring agent, which in turn creates: Temperature agent*. Battery agent. CPU utilisation agent. Heap memory agent. The transmitter and receiver calculate the bandwidth through the proxy for each iteration. The data gathering agent collects the results and passes them to the librarian agent. The librarian agents stores the results in output text files.

18 Proxy-based Bandwidth of PDAs Bandwidth Kbits/s Jeode CrEme JRE 1.3 Familiar Linux PocketPC 2003 PocketPC 2002 J9 The bandwidth offered by the proxy device highly depends on: The JVM used. The OS used. The highest bandwidth is achieved by PocketPC 2003 CrEme The lowest bandwidth is achieved by Jeode and J9 for PocketPC 2002.

19 Discharge rates for PDAs while acting as proxies Discharge rate (s) Familiar Linux PocketPC 2003 PocketPC 2002 The battery discharge rate ranges from 60 (s) - 70 (s). Familiar Linux applies better battery conservation mechanisms: Extends battery life by 30%, compared to PPC2003. Extends battery life by 35%, compared to PPC2002. J9 extends the battery life by 15%, compared to CrEme for PPC2003. However, the bandwidth is significantly lower

20 CPU utilisation of PDAs while acting as proxies CPU (%) Familiar Linux PocketPC 2003 PocketPC 2002 CPU utilisation while routing is ranging between 65% - 85%. JRE is the heaviest JVM. The lightest are Jeode and J9. CrEme is heavy as well requiring 80% of the CPU. Routing is a CPU-intensive task. The OS does not play a significant role in CPU utilisation.

21 Heap memory usage of PDAs while acting as proxies Heap (KB) Familiar Linux PocketPC 2003 PocketPC 2002 Heap memory is the memory used by Java objects to perform their tasks. Significant differences can be observed from the graph: CrEme and JRE 1.3 are the most heap-intensive JVMs. Others, are utilising similar heap memory. Heap memory usage seems to have a strong link to bandwidth: The higher the Heap memory usage the higher the bandwidth.

22 Internal temperature variation of PDAs while acting as proxies Celsius (C 0 ) J9 JRE 1.3 JRE 1.3 J9 Temperature readings were taken for each battery discharge by 1%. The overall variation in battery has been calculated. The proxy devices running J9 experiences faster increases in the overall temperature. This may be associated to the fact that J9 provides higher bandwidth than JRE 1.3/

23 Overview - Bandwidth of C/S and Proxy-PDAs Bandwidth (Mbits/s) Bandwidth (Kbits/s) PDA: Client - Server PDA: Proxy Minimum Maximum Client-Server, PDA: 4-5 Mbits/s. Client-Proxy-Server, PDA: 3-70 Kbits/s. Client-Proxy-Server, Laptop (medium powered device): Kbits/s. Client-Proxy-Server, Workstation (high powered device): Kbits/s Workstation Laptop PDA

24 06:00:00 04:48:00 03:36:00 02:24:00 01:12:00 00:00:00 Overview- Battery life of PDAs hh/mm/ss IDLE Wireless Routing Familiar PPC2003 PPC2002 Familiar Linux. IDLE: 5 hours and 25 minutes Wireless: 3 hours and 12 minutes. Routing: 2 hours and 18 minutes. PocketPC 2003 IDLE: 4 hours and 32 minutes. Wireless: 2 hours and 03 minutes. Routing: 1 hour and 50 minutes. PocketPC IDLE 3 hours and 58 minutes. Wireless: 1 hour and 58 minutes. Routing: 1 hour and 45 minutes.

25 Overview - Proxy results Proxy efficiency depend on: JVM used. OS used. Resources consumption on proxy-pdas is high in terms of: Battery life, CPU utilisation, Heap memory usage, and Temperature. PocketPC 2002 Jeode and J9 perform equally for PocketPC CrEme provides almost 3 times more bandwidth and utilises 3 times more heap memory than Jeode and J9. PocketPC J9 improves its bandwidth by 30% compared to PocketPC CrEme provides 6 times more bandwidth compared to PocketPC and utilises 4 times more heap memory. Familiar Linux. J9 provides 12 times more bandwidth compared to PocketPC 2002 and 8 times more compared to PocketPC It also adds 25 minutes battery life. JRE 1.3 is quite efficient for such a heavy JVM. It provides moderate bandwidth and doesn t over-consume resources. The stronger combination bandwidth-wise, is PocketPC 2003 with CrEme. A second alternative is Familiar Linux with J9, which achieves moderate bandwidth keeping the utilisation of resources quit low.

26 BASS Benchmarking multi-agent Software System BASS is a Java-based, light-weighted, multi-agent software system that is able to run on mobile devices. The purpose of BASS is to: Determine the fitness of mobile devices by performing standard tests: Group level tests: Operating System version. JVM version, and so on. Kernel-level tests: CPU tests: bubble sort and merge test. Memory and hard-drive tests. Monitor utilisation of devices: Network level tests: Bandwidth and latency. Error packets monitoring. Internet connectivity. Utilisation monitoring: Overall memory and CPU usage. Produce metrics which can later be used by the routing protocol to decide on optimal routes.

27 S Routing scenario (1) X S X Z Z Y Y W W High bandwidth Moderate bandwidth Low bandwidth Node OS JVM X Pocket PC 2003 CrEme Y PocketPC 2002 Jeode Z Familiar Linux J9 D Node X Y Z W Device PDA Laptop PDA PDA OS JVM Pocket PC 2003 CrEme Windows XP JRE 1.4 Familiar Linux JRE 1.3 PocketPC 2002 CrEme W PocketPC 2002 Optimal route from S to D: S -> X -> Z -> D J9 Optimal route from S to D: S -> Y ->W or Z -> D D

28 S Node X Y Z W X Battery life low high high moderate Y CPU utilisation high low low low Z Routing scenario (2) Node OS JVM X Pocket PC 2003 CrEme Y PocketPC 2002 Jeode Z Familiar Linux J9 W W PocketPC 2002 J9 Memory usage high low low low D Temperature moderate low low low Optimal route from S to D, bandwidth-wise: S -> X -> Z -> D However, X has: Low battery. High CPU utilisation. High memory usage. To be energy efficient, and light-weighted: Route will be: S -> Y -> Z -> D

29 Conclusions We have proved the concept of a proxy-pda and showed that it may be a good alternative to proper routing software due to its: Low implementation effort. Light-weighted nature. We have ported various JVMs to various OSs for ipaq PDAs. Familiar Linux: Blackdown JRE 1.3 and IBM J9. PocketPC 2003: IBM J9 and NSIcom CrEme. PocketPC Insignia Jeode, IBM J9, and NSIcom CrEme. We have proved that the OS and the JVM used can play an important role in the efficiency of the proxy-pda in terms of bandwidth, battery discharge rate, CPU utilisation, heap memory, and temperature. We have identified the best pair as being: PocketPC 2003 with CrEme and as an alternative to lower utilisation of PDA s resources with moderate bandwidth being: Familiar Linux with J9. We have shown the importance of BASS, which can be incorporated with MARIAN, in order to assist in metric-driven routing taking into account: Performance characteristics. Current Utilisation. Extensive research will now be concentrated in building up a scalable model for direct and indirect communication range network discovery and indirect. The next stage includes simulating MARIAN using Network Simulation (NS 2) and compare its performance to traditional routing protocols such as DSR, AODV, and so on.

30 Publications IEEE ECBS 2003 Mobile Agents for Routing, Topology Discovery, and Automatic Network Reconfiguration in Ad-hoc Networks. IADIS WWW/Internet 2003 MARIAN: A framework using Mobile Agents for Routing In Ad-hoc Networks. IEEE ECBS 2004 Migration of Mobile Agents in Adhoc, Wireless Networks Elsevier Journal of Ad-Hoc Networks (2004) Analysis of an Agent-based Metric- Driven Method for Ad-hoc, On- Demand Routing

31 Questions Thank you!!!