OLSR + FSR for Scalability in Mesh Networks Date: 2004-03-09 Authors: Notice: This document has been prepared to assist IEEE 802.11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures <http:// ieee802.org/guides/bylaws/sb-bylaws.pdf>, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair <stuart.kerry@philips.com> as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at <patcom@ieee.org>. Maniezzo et al. UCLA

Outline Optimize Link State Routing (OLSR) Protocol Overview Pros and Cons Fisheye State Routing (FSR) Merging OLSR and FSR Simulation Results Conclusions Maniezzo et al. UCLA

Optimized Link State Routing (OLSR): Protocol Overview Proactive link-state routing protocol Periodic topology information exchange. Optimization of Link State algorithm Defines a subset of one-hop neighbors (MPR, MultiPoint Relay) that cover all the nodes that are two hops away. MPR: Minimize the amount of link-state information Reduce the number of nodes that mast transmit the broadcast packets such as the Topology Control (TC) packets. Maniezzo et al. UCLA

OLSR: Protocol Architecture Periodic Hello messages exchange (broadcast packets with TTL=1) Exchange neighbor list Check the status of the link with 1-hop neighbors Acquire topology information of 2-hops neighbors Periodic Topology-Control Messages exchange (broadcast packet with TTL=max) Source address Address of each node in the MPR selector set Compute the MPR i.e. the one hop relay required to reach the 2-hops neighbors 1-hop neighbors 2-hops neighbors MPR of central node Only the node on the MPR of the sender retransmit the TC packets Maniezzo et al. UCLA

OLSR: Pros and Cons Perfect Network Topology at every node Minimization of the routing overhead using MPR Flooding of topology information in all the network Not suitable for large networks Maniezzo et al. UCLA

Fisheye State Routing (FSR): Protocol Overview Proactive link-state routing protocol. Similar to LS as it maintains a full topology map at each node Periodic exchange of Hello packet. Periodic exchange of topology tables within the local neighbors only (instead of flooding the entire network) . Topology tables update frequency decreases with distance to destination Updates for a near destination are propagated more frequently then updates for a remote destination Maniezzo et al. UCLA

FSR: Protocol Overview (cont’d) Central Node 1-hop neighbor 2-hops or more neighbor Scope 1 Scope 2 The link state updates are sent every 2kT to all the node in scope k where K is the hop distance T is the minimum link state updates transmission period Maniezzo et al. UCLA

FSR: Protocol Overview (cont’d) Highly accurate routing information about the immediate neighborhood of a node; progressively less detail for areas further away from the node FSR achieve potential scalability by limiting the scope of link state update dissemination Maniezzo et al. UCLA

FSR: Pros and Cons Minimization of the flooding using the “scope” concept Suitable for dense network Not perfect Network topology knowledge Multiple Routing Packets received at the same node Maniezzo et al. UCLA

Merging OLSR and FSR Final protocol based on OLSR with the addition of “scope” concept Every node divides the network in “scope” and maintains information about nodes in a “scope” depending of the distance. With the new protocol, a node reports the TC packets to “far-away” nodes less frequent. Maniezzo et al. UCLA

Simulation Scenario 100 nodes, uniformly placed in a 1600mX1600m field. IEEE 802.11 MAC DCF channel rate = 2Mbps radio range = 367 meters. Node mobility model randomly waypoint mobility model pause time = 10 seconds. maximum mobility speed = minimum mobility speed variable. 10 random CBR/UDP flows packet size = 1000 bytes packet interval = 5 packets per second Simulation time = 450 seconds. The OLSR+FSR scheme use scope width as 2 hops and totally 4 scopes. Maniezzo et al. UCLA

Simulation Results Maniezzo et al. UCLA

Simulation Results (cont’d) Maniezzo et al. UCLA

Simulation Results (cont’d) Maniezzo et al. UCLA

Simulation Results (cont’d) Maniezzo et al. UCLA

Conclusions From above comparison figures, clearly we observe the advantages of the OLSR + FSR routing. Good performance is observed even when update interval of hello message is 1 second. And when mobility is high, the performance improvement is significant. The average data packet end-to-end delay is also significantly reduced. Overhead reduction is also clearly demonstrated. From the comparison, we conclude that OLSR + FSR is a good way to improve the routing scalability to node mobility. Maniezzo et al. UCLA

Any idea or other suggestions? Maniezzo et al. UCLA