Architecture & Protocols for Supporting Routing & QoS in MANET.

Transcription

1 Architecture & Protocols for Supporting Routing & Navid NIKAEIN QoS in MANET Navid Nikaein 2003

2 Outline Introduction: Issues and Trade-Offs Related Work Architecture Topology Management Route Determination Quality of Service Support Conclusion and Open Issues

3 Issues in MANET Mobile ad hoc networks: Wireless low-capacity Collision Mobility time-varying resources Lack of infrastructure fully-distributed Small devices Limited resources Link failure Multihop Routing Routing & QoS

4 Routing Issues Dilemma at a node: Do I keep track of routes to all destinations, or instead keep track of only those that are of immediate interest? Three strategies: Proactive: keep track of all. Reactive: only those of immediate interest. Hybrid: partial proactive / partial reactive. Trade-off between routing overhead and delay

5 QoS Routing Issues State of communication path should be considered in QoS routing: Resource availability and its stability Cause longer path than shortest path Trade-off between shortest path and optimal path

6 Assumption Fully symmetric environment All nodes have identical capabilities Capabilities: Transmission range, Battery life, processing capacity, buffer capacity Each node periodically sends a Beacon All nodes participate in protocol operation and packet forwarding [Michardi, Molva, Crowcroft]

7 Related Work Ad Hoc Routing Topology-based Position-based Proactive Reactive Hybrid Proactive Reactive Hybrid OLSR TBRPF DSDV WRP CGSR FSH-HSR LANMAR DSR AODV RDMAR ABR SSR TORA ZHLS ZRP CBRP DDR+ HARP DREAM LAR Terminodes GLS ALM

8 Architecture AN ARCHITECTURE THAT SEPARATES [1]: Route Determination With respect to Application requirements Topology Management With respect to Quality of Network Application HARP DDR Network QoS Classes QoS: Delay TPut BE Network Quality QoC: Power, buffer Stability Protocol stack QoS extension

9 Outline Topology Management [2,3] DDR- Distributed Dynamic Routing Algorithm Route Determination HARP- Hybrid Ad hoc Routing Protocol Quality of Service Routing LQoS- Layered Quality of Service

10 Topology Management Intuition DDR- Distributed Dynamic Routing Algorithm Forest Construction Zone Partitioning Zone Behaviors Simulation Model Performance Results Summary

11 Intuition Generate a set of preferred paths in the network Criteria Network Topology Forest BEACON TREE TREE. TREE ZONE ZONE. ZONE BEACON Time

12 Forest Construction Each node select the best node in its neighborhood according to the given unique criteria, e.g. degree If identical nodes, select the one with the higher ID Theorem: Connecting each node to its preferred neighbor yields to a forest [2] MPR-tree [Qayyum] used in OLSR [Jaquet] Forest Reduces the number of forwarding nodes 2 4 b a 3 c d 4 5 f e 3 g 3 1 h

13 Zone Partitioning Tree Zone Maintained using periodical beaconing a b f s c k y t d g w x v z i u e h n DDR a z 1 b f s c k y t d x i g v z 2 w u e z h n Zones : Improves delay performance Contributes in protocol scalability z 3

14 Criteria for FC [4]: Quality of Connectivity (QoC) Power level p battery lifetime Buffer level b available unallocated buffer Stability level s t=t 1 -t 2 : period s( x) = QoC = α s + β b (+ δ p ) N I N The set of forwarding nodes belongs to the nodes with the high quality N t t 0 0 U N t t 1 1

15 Zone Behaviors Whatever the network density is, the zone diameter is bounded to 8 The average ratio of tree-path to shortest path is no longer than 2 Low Complexity O(N) Zone Diameter Tree Path / Shortest Path

16 Protocol Model To study the effect of the proposed topology management on routing performance? Hybrid Ad Hoc Routing Protocol (HARP) [5] Dual mode: node level and zone level Intra-zone and inter-zone routing Discover the shortest path Establish forward and reverse path Maintenance

17 Simulation Model [Johansson, Perkins, Broach] Traffic model: CBR 512 byte/packet 4 packets/second Source 10, 20, 30 Performance Metrics: Packet delivery fraction Avg. E2E delay Routing overhead Movement model: Random way point [Yoon] 50 nodes 1500mx300m 0-20 m/s (or 1-20m/s) 900 simulated seconds Pause time=0, 30, 60, 150, 300, 600, scenarios for each pause time

18 Packet Delivery Fraction Simple routing has a slightly better PDF in low traffic load Routing+TM outperforms simple routing up to 20% as the traffic load increases 10 sources 20 sources 30 sources

19 Avg. E2E Delay Routing +TM significantly improves the delay performance up to 200ms as the network conditions become stressful 10 sources 20 sources 30 sources

20 Routing Overhead (pkt) Simple Routing outperforms Routing+TM in low/medium traffic load Most of the packets produced by Routing+TM are the beacons Reaction to link failure : Beacon vs. PREQ Forest does reduce the broadcasting overhead NOTE: Beacon is local while PREQ is global 10 sources 20 sources 30 sources

21 Routing Overhead (bytes) Simple Routing outperforms Routing+TM in low/medium traffic load Forest does reduce the broadcasting overhead 10 sources 20 sources 30 sources

22 Packet Delivery Fraction The effect of mobility rate and traffic load on PDF The fluctuation The congestion Adaptive Routing Fluctuation Fluctuation Congestion 10 sources 20 sources 30 sources

23 Avg. E2E Delay The effect of mobility rate and traffic load on DELAY Shortest path is not enough! The load balancing Note: QoC = α s + β b, where α =2 & β = 1 Shortest path is not enough Load Balancing 10 sources 20 sources 30 sources

24 Summary Overall Performance Low traffic load Medium traffic load High traffic load Low Mobility Routing Similar Medium Mobility Routing High Mobility Similar Routing +TM Routing +TM Routing +TM Routing +TM Routing +TM

25 Outline Topology Management DDR- Distributed Dynamic Routing Algorithm Route Determination [5,6] HARP- Hybrid Ad hoc Routing Protocol Quality of Service Routing LQoS- Layered Quality of Service

26 Route Determination [5,6] HARP- Hybrid Ah Hoc Routing Protocol Intra-zone and Inter-zone routing Query localization technique [Aggelou, Tafazolli] Performance Results [Osafune] Summary

27 Routing Intra-zone Routing a b z 1 f s r c k d y t m x i g z 2 w v u e z 3 z h n Inter-zone Routing src zone Zone abstraction Z1 Z2 Z4 Z3 dst zone z 4 Shortcut intra-zone routing - Zone level routing - Distance estimation

28 Simulation Model [Johansson, Perkins, Broach] Traffic model: CBR 512 byte/packet 4 packets/second Source 10, 20, 30 Performance Metrics: Packet delivery fraction Avg. E2E delay Routing overhead Movement model: Random way point [Yoon] 50 nodes 1500mx300m 0-20 m/s (or 1-20m/s) 900 simulated seconds Pause time=0, 30, 60, 150, 300, 600, scenarios for each pause time

29 Packet Delivery Fraction The effect of mobility and traffic load is not uniform Congestion stems from the lack of load balancing in the protocols Fluctuation point is a function of network parameters The effect of cashing and/or neighboring table in high mobility Fluctuation Congestion 10 sources 20 sources 30 sources

30 Avg. E2E Delay The effect of traffic load and mobility on the delay performance is non-uniform Caching (DSR), route request (AODV), and beaconing/preq (HARP+TM) Load balancing Load balancing 10 sources 20 sources 30 sources

31 Routing Overhead (pkt) Reaction to mobility (main cause of link failure) Caching (DSR), route request (AODV), beaconing and PREQ (HARP+TM) Effect of beaconing on battery lifetime [Toh] No handshaking is required for beaconing 10 sources 20 sources 30 sources

32 Routing Overhead (bytes) Reaction to mobility (main cause of link failure) Caching (DSR), route request (AODV), beaconing and PREQ (HARP+TM) Effect of beaconing on battery lifetime [Toh] No handshaking is required for beaconing 10 sources 20 sources 30 sources

33 Summary Overall Performance Low traffic load Medium traffic load High traffic load Low Mobility Medium Mobility HARP HARP HARP +TM +TM +TM HARP +TM High Mobility HARP +TM Similar Similar HARP +TM HARP +TM

34 Outline Topology Management DDR- Distributed Dynamic Routing Algorithm Route Determination HARP- Hybrid Ad hoc Routing Protocol Quality of Service Routing [7] LQoS- Layered Quality of Service

35 Quality of Service Routing [8] Motivation Architecture and Intuition Network Metrics Application Metrics Performance Results

36 Motivation Application QoS Network QoC Whether the communication path can support any particular application delay, or bandwidth? Ad Hoc QoS means to provide a set of parameters in order to adapt application to the quality of communication path while routing through the network [7]

37 Architecture AN ARCHITECTURE THAT SEPARATES [8]: Application HARP DDR Network QoS Classes App. Metrics Delay TPut BE Network Metrics: QoC: Power, buffer Stability, # hops Path selection phase Path Discovery phase Protocol stack QoS extension

38 Network Metrics Hop count resource conservation Power level Buffer Level Load balancing Stability Level Trade-off between load balancing & resource conservation Compute during path discovery using concave function Reflect the quality of the communication paths Map this quality to application metrics

39 Application Metrics Service App. Metrics Net. Metrics Legend 1st Class 2nd Class Delay Throughput h.(r-b)/c c/(2h.(r-b)) h : hop count r : buffer size b : buffer occupancy 3rd Class Best-Effort 1/s c : nodes throughput s : stability Compute during path selection Reflect the quality of service requirement

40 Avg. E2E Delay Delay performance has significant improved QoS metric is the key factor for the delay performance due to its load balancing effect 10 sources 20 sources 30 sources

41 Packet Delivery Fraction QoS metrics has no significant effect on PDF Route discovery and route maintenance are the key factors for improving PDF Deal with Traffic load/pattern and mobility model/rate 10 sources 20 sources 30 sources

42 Conclusion- Architecture Pro-Network Routing Pro-Application Topology management Route determination Quality of connectivity (QoC) Quality of Service (QoS)

43 Conclusion Topology management improves routing Load balancing HARP QoS metrics DDR QoC metrics Control flooding overhead Forest redundancy & collision Query localization technique scope Scalability zone abstraction

44 Conclusion Routing requires: Adaptive topology management Load balancing Congestion avoidance mechanisms Neighboring information Factors affecting routing performance Network size, mobility rate and model, traffic load and pattern, network density Traffic locality vs. network size

45 Future Work Optimal criteria of forest Construction Introduce an adaptive routing mechanisms Extend the QoS model to support metrics at the link layer (e.g. SNR)

46 Publications [1] N. Nikaein and C. Bonnet, An Architecture for Improving Routing and Network Performance in Mobile Ad Hoc Network, Kluwer/ACM MONET, [2] N. Nikaein, H. Labiod, and C. Bonnet, DDR-- Distributed Dunamic Routing Algorithm for Mobile Ad Hoc Networks, MobiHoc, [3] N. Nikaein, S. Wu, C. Bonnet and H. Labiod, Designing Routing Protocol for Mobile Ad Hoc Networks, DNAC, [4] N. Nikaein and C. Bonnet, Improving Routing and Network Performance in MANET using Quality of Nodes, WiOpt, 2003

47 Publications [5] Navid Nikaein, C. Bonnet and Neda Nikaein, HARP- Hybrid Ad Hoc Routing Protocol, IST, [6] Navid Nikaein, C. Bonnet, N. Akhtar and R. Tafazolli, HARP-v2 Hybrid Ad Hoc Routing Protocol, To be submitted, [7] N. Nikaein and C. Bonnet, A Glance at Quality of Service models in Mobile Ad Hoc Networks,DNAC, [8] N. Nikaein, C. Bonnet, Y. Moret and I. A. Rai, LQoS- Layered Quality of Service Model for Routing in Mobile Ad Hoc Networks, SCI, [9] N. Nikaein and C. Bonnet, ALM-- Adaptive Location Management Model Incorporating Fuzzy Logic For Mobile Ad Hoc Networks, Med-Hoc-Net, 2002.

48 Architecture

49 Problem Definition? Trade-off between routing overhead and delay while maximizing network utilization Trade-off between load balancing and resource conservation Separation between topology management and route determination What are the design elements of routing and how they must interact?

50 Zone Behaviors As the number of zone increases, the overhead within a zone decreases but the overhead between zones increases Whatever the network density is, the zone diameter is bounded to 8 What is the optimal number of zones to achieve the minimum overall overhead? M opt < N Number of Zones Size of Zones Diameter of zones

51 Buffer Drop Distribution for No/Low Mobility with High Load

52 Delay Distribution for No and Low Mobility

53 Query Localization Technique Offset= mobility x elapsed time SRC DST Src Offset d x R RD_Offset Dst Offset

54 Query Localization Technique Offset= mobility x elapsed time SRC DST Src Offset d x R RD_Offset Path_offset

55 Query Localization Technique if (rd(x,dst)>rd(src,d)) Drop PREQ; else if (rd(x,dst)<ttl) TTL=rd(x,dst); x PREQ src PREQ x d=k d=3 d=2 d=1 dst

56 QoS Mapping IP QoS Class Radio QoS Class IntServ DiffServ 1st Class Low delay/high dropping 2nd Class Medium delay/medium dropping 3rd Class High delay/low dropping Guaranteed Service Controlled Load Best Effort Expedited Forwarding Assured Forwarding Best Effort

57 Example A path of lower hop count has higher delay, because of high buffering delays. The other path of a possibly higher hop count, but lower delay. (also load balancing).

58 Stability Level Node mobility a basic characteristic of ad hoc networks. A point of difference from wired networks. Critical to capture this node mobility in the routing protocol in order to determine stable, reliable routes. We propose: stab( x) = N N t t 0 0 I U N N t t 1 1 N to : neighbors at time to. N t1 : neighbors at time t1.

59 Stability Level stab( x) = N N t t 0 0 I U N N t t stab(x) 1 stab (x) = 1 high stability, stab (x) = 0 low stability Numerator: nodes that have remained in the neighborhood of x. High stability if none (few) of its neighbors change, low stability if many (all) of its neighbors change.

60 Stability Example: /4 1/2 1 0 t 0 t 1 Stability also reflects connectivity. A large degree node, in general, more stable.

61 NLM Evaluation of a Path In path generation, NLM are propagated through the nodes of generated paths. For a path P = <s, n 1, n 2,, n k, d> P.hop = n P\{s} 1 P.power = min n P\{s, d} n.power P.buffer= ( n P\{s, d} n.buffer) / (P.hop - 1) P.stability= min n P\{s} n.stability

62 Service differentiation Class I Class II 60% 30% Outgoing traffic Class III 10%

63 Status Concept A node broadcasts is QoS state itself. This QoS state reflects node s ability to act as a router. If selfish, then ceases to act as a router, doesn t take part in routing protocol. Since propagated by the node itself, the possibility of lying. (malicious behavior) pretend to be in selfish mode, to avoid being chosen for forwarding.

64 Status Concept A selfish node does not serve the network (does not route), hence, fair that it receives poor services from the network. Status: the fraction of time a node has been in unselfish mode to the network. The status of node y at node x: R[ y] = Nu[ y] N[ y] N u [y] : number of y s beacons in unselfish mode. N [y] : total number of y s beacons received.

65 Status Concept How to prevent malicious behavior? Give a status to each node, and give incentive to a node to act as a router. If a node acts as a router, then it is not in selfish mode. Prefer packets generated by unselfish nodes while routing. Hence, a node that has remained selfish, receives poor services from the network.

66 DMPDC Modify MRDC to adapt the infrastructure offered by DDR in order to Improve bandwidth efficiency Speed up link error detection and recovery Use DDR s forest to broadcast Core Advertisement message Use DDR s intra-zone routes Reduce multicast tree maintenance cost Benefit from DDR s periodical intra-zone route update Use DDR s neighborhood knowledge to detect link failure