1. DYMO: Dynamic MANET On-Demand  IETF Draft submitted by MANET WG  Work in progress  Descendant of DSR and AODV  A rewrite of AODV, using different terminology and packet format, but having the same basic functionality  Table driven routing Significantly smaller amount of routi ng information than DSR  Path accumulation (cf. DSR) is optional  No precursor list in routing table entries  Makes use of the generalized MANET packet format  Extensible through TLVs  Basic Internet connectivity  AODV and DSR are not consider Internet access  DYMO maintains routing tables with gateway and prefix information  DYMOcast  Packet transmission to all MANET routers within reception range  Broadcast in IPv4 or all node multicast in IPv6  Maintaining Local Connectivity may use any mechanisms  Link layer feedback difficulty of obtaining IEEE 802.11 feedback in real networks  Hello messages periodic one-hop L3 message many ad hoc networks utilize hello messages depends on many factors such as loss settings, message size, rate,...  Neighbor discovery relay highly on broadcast/multicast capabilities of the underlying link layer need optimization  Route timeout difficulty of determining the proper timeout because of dynamic mobility 1

2. DYMO – Route Discovery  Similar to the route discovery of the AODV  DYMO uses only RE although AODV and DSR use RREQ, RREP  DYMOcast RE with A flag: Route Request  Unicast RE: Route Reply  RE packet format 2

3. DYMO – Route discovery Comparison 3 DSRAODVDYMO Path way Bi-directionOptional bi- direction Bi-direction Seq. number XOO Message type RREQ, RREP RE Message information Path- accumulation No path- accumulation Optional path- accumulation The other features Caching Multi-path Pre-cursor listHandling unsupportable message, Fixed control packet header

4. Flooding  Advantages  Simplicity  May be more efficient than other protocols when rate of information transmission is low enough  Potentially higher reliability of data delivery Multiple path  Disadvantages  Potentially, very high overhead  Potentially lower reliability of data delivery Flooding uses broadcasting -- hard to implement reliable broadcast delivery without significantly increasing overhead –Broadcasting in IEEE 802.11 MAC is unreliable  nodes J and K may transmit to node D simultaneously, resulting in loss of the packet 4

5. Flooding of Control Packets  Used for route discovery  How to reduce the scope of the route request flood ?  LAR  Query localization  How to reduce redundant broadcasts ?  The Broadcast Storm Problem 5 Collision!

6. TORA: Temporally-Ordered Routing Algorithm [7-12]  A source-initiated on- demand routing protocol which use a link reversal algorithm  Provides loop-free multi- path routes to a destination node  Route establishment function is performed only when a source does not have any directed link  Query/Update  Height of node from the destination 6

7. TORA Route Maintenance  When a partition is detected, all nodes in the partition are informed, and link reversals in that partition cease 7

8. LAR: Location-Aided Routing [7-13]  Utilizes the location information (form GPS) to reduce the control packets overhead  Flooding is restricted to a small RequestZone  LAR1 algorithm 8  LAR2 algorithm  RREQ packet includes the distance S between source and destination  When an intermediate node i receives RREQ, computed the distance DISTi to the destination If DISTi < S + δ, forward RREQ Otherwise, discard

9. DREAM : Distance Routing Effect Algorithm for Mobility 9

10. ABR: Associativity-Based Routing [7-14]  A beacon-based on-demand routing protocol  Selects routes based on the stability of the wireless link  Only links that have been stable for some minimum duration are utilized  motivation: If a link has been stable beyond some minimum threshold, it is likely to be stable for a longer interval. If it has not been stable longer than the threshold, then it may soon break (could be a transient link)  Association stability determined for each link  measures duration for which the link has been stable  Prefer paths with high aggregate association stability 10

11. SSA: Signal Stability Based Adaptive Routing [7-15]  Similar to DSR  Signal strength is measure for determining signal stability  Strong/stable link  Weak/unstable link  A node X re-broadcasts a Route Request received from Y only if the (X,Y) link is deemed to have a strong signal stability  Signal stability is evaluated as a moving average of the signal strength of packets received on the link in recent past  An alternative approach would be to assign a cost as a function of signal stability 11

12. Hybrid Routing Protocols 12

13. ZRP: Zone Routing Protocol [7-18]  Routing zone of a given node: a subset of the network, within which all nodes are reachable within less than or equal to zone radius hops  Intra-zone routing (IARP): employs proactive routing  Inter-zone routing (IERP): uses reactive routing  Source S checks whether destination D is within its zone  Source If D is within S’s zone, deliver the packet directly Otherwise, bordercast the RREQ to its peripheral nodes  Peripheral nodes If any peripheral node finds D to be its routing zone, it sends RREP back to S Otherwise, re-bordercast RREQ 13

14. ZHLS: Zone-Based Hierachical Link State Routing Protocol [7-19]  A hybrid routing protocol  Intra-zone routing: Proactive routing link state algorithm (SPF)  A hierarchical routing protocol  Reactive routing  Forms non-overlapping zones, using the geographical location information of the nodes  Hierarchical address: (zone ID, node ID)  Zone-level connectivity Zone LSP are propagated by the gateway nodes 14

15. Hierarchical Routing Protocols 15

16. HSR: Hierarchical State Routing [7-23]  A distributed multi-level hierarchical routing protocol  Employs clustering at different levels  Clustering enhances resource allocation and mgmt e.g) allocation of different frequency or spreading codes to different clusters  Physical clustering, logical clustering  Link state information is broadcast within the cluster at regular intervals  Cluster leader exchanges the topology and link state routing information with neighbor clusters 16

17. FSR: Fisheye State Routing [7-23]  To reduce information to represent graphical data for reducing routing overhead  Keep accurate information about near nodes, but not- so-accurate information about far-away nodes  Hybrid approach  Link-level information exchange: use distance vector protocol  Network topology information : link state protocol  Frequency of exchange decreases with an increase in scope 17

18. Power-Aware Routing Protocols 18

19. Power-Aware Routing Metrics  Minimal energy consumption per packet  Maximize network connectivity  Minimum variance in node power levels  Distribute the load among all bodes  Minimum cost per packet  Remaining battery charge  cost factor for routing  Minimize maximum node cost  Minimize the max cost per node for a packet after routing a number of packets or after a specific period  This delays the failure of a node 19

20. Power-Aware Routing  [Singh98Mobicom,Chang00Infocom]  Define optimization criteria as a function of energy consumption. Examples:  Minimize energy consumed per packet  Minimize time to network partition due to energy depletion  Maximize duration before a node fails due to energy depletion  Assign a weigh to each link  Weight of a link may be a function of energy consumed when transmitting a packet on that link, as well as the residual energy level  low residual energy level may correspond to a high cost  Prefer a route with the smallest aggregate weight  Possible modification to DSR to make it power aware (for simplicity, assume no route caching):  Route Requests aggregate the weights of all traversed links  Destination responds with a Route Reply to a Route Request if it is the first RREQ with a given (“current”) sequence number, or its weight is smaller than all other RREQs received with the current sequence number 20