Routing in wireless networks

Transcription

1 Routing in wireless networks. Pham Université de Pau et des Pays de l dour épartement Informatique ongduc.pham@univ-pau.fr

2 Routing in wireless networks What s a wireless network? Wireless terminals mbedded Mobility With or without a fixed infrastructure With or Without a centralized administration onnected to the Internet or autonomous xemples SM Wii, WiMax luetooth d-oc, Manet Wireless Sensor Networks Vehicle network ours de. Pham, Université de Pau et des Pays de l dour Routage 2

3 d-hoc networks Infrastructure-less networks MNT (Mobile dhoc NTworks) ours de. Pham, Université de Pau et des Pays de l dour Routage 3

4 esign choices (1) Single-hop or multi-hop? Single-path or multi-path? ours de. Pham, Université de Pau et des Pays de l dour Routage 4

5 esign choices (2) Proactive? Maintain & update routing table independently of communication needs Periodical updates Same philosophy than in wired-networks (RIP, OSP) Low latency «Waste» bandwidth and energy Reactive, on-demand? On-the-fly discovery of routes, when communication needs appear Save bandwidth and energy igher latency enerally efficient at low load ybrid? Proactive or reactive depending on the distance ours de. Pham, Université de Pau et des Pays de l dour Routage 5

6 esign choices (3) lat routing? Simple Not scalable! ierarchical routing? More efficient «leaders» election overhead Mobility cost Multiple hierarchy levels are possible eographical routing? PS-aided for instance fficient routing towards the destinations eographical information are propagated using flooding ours de. Pham, Université de Pau et des Pays de l dour Routage 6

7 Structuration of the network esired properties ide topology changes (stability) Structure the network (hierarchy) Optimize information diffusion Take into account the heterogeneity of nodes istributed «backbone» approaches «clustering» approaches ours de. Pham, Université de Pau et des Pays de l dour Routage 7

8 lassification ours de. Pham, Université de Pau et des Pays de l dour Routage 8

9 xample: : OV Initiated when a communication need arises: reactive Source node initiates path discovery by broadcasting a route request (RRQ) packet to its neighbors neighbor either broadcasts the RRQ to its neighbors or satisfies the RRQ by sending a RRP back to the source Later copies of the same RRQ request are discarded Node records the address of the sender of RRQ (indicated in the RRQ) Reverse path are automatically set-up ntries are discarded after a time-out period ventually, a RRQ arrives at a node that possesses the current route for the destination (omparison of sequence numbers) The RRP travels along the path established in the reverse path set-up ach node along the RRP journey sets up a forward pointer, updates time-out entries, records the destination sequence number of requested destination ours de. Pham, Université de Pau et des Pays de l dour Routage 9

10 OV (xample) Y L S P I T Z RRQ

11 OV (xample) Y L S P I T Z Reverse Path Setup

12 OV (xample) Y L S P I T Z

13 OV (xample) Y L S P I T Z

14 OV (xample) Y L S P I T Z RRP

15 OV (xample) Y L S P I T Z orward Path Setup

16 OV (xample) Y L S P I T Z

17 OV (xample) Y L S P I T Z

18 OV (xample) Y L S P I T Z

19 xample: : OLSR Proactive protocol, similar to Link State with LLO packets Uses «multipoint relay» to reduce information diffusion costs «multipoint relay» of node are nodes N such that all 2-hop neighbors of are 1-hop neighbors of N. x: & are multipoint relay of Node with information from ours de. Pham, Université de Pau et des Pays de l dour Routage 19

20 OLSR (con( con t) Nodes & send information from Nodes & are multipoint relays of Node send information from Node with information from ours de. Pham, Université de Pau et des Pays de l dour Routage 20

21 Other protocols omework for next week ind another proactive or reactive protocol (Internet search) Understand it, explain it in front of class ompare it to OV and/or OLSR ours de. Pham, Université de Pau et des Pays de l dour Routage 21