1. INRIA Hitachi Ecole Polytechnique 1 MPR Extension for OSPF on MANETs draft-baccelli-ospf-mpr-ext-01.txt Emmanuel Baccelli 65 th IETF OSPF WG in Dallas, March 23 rd 2006

2. INRIA Hitachi Ecole Polytechnique 2 Agenda 1.MANET-OSPF background 2.Topology reduction with MPR links 3.Flooding optimization with MPR extension

3. INRIA Hitachi Ecole Polytechnique 3 Keys to efficient OSPF on MANETs MANET-OSPF DT results: –Need overhead reduction –Need to focus on LSUpdate Reduction can be achieved: –with flooding optimization –with topology reduction –with adjacency limitation benchmark results Henderson, Spagnolo et al.

4. INRIA Hitachi Ecole Polytechnique 4 OSPF extensions for MANET ● No change to traditional OSPF – Existing code/protocol unaltered – MANET “instabilities” won’t affect OSPF stability – Leverage existing code/mechanisms ● Changes concern only OSPF MANET interfaces – Specific MANET interface type addressing: ● highly dynamic topology, scalability, radio link fading ● draft-baccelli-ospf-mpr-ext-01 proposes: – topology and adjacency reduction – flooding optimization

5. INRIA Hitachi Ecole Polytechnique 5 MPR: Multi-Point Relays MPR selects a subset of links and nodes to achieve optimized network coverage. MPR

6. INRIA Hitachi Ecole Polytechnique 6 ● MPR yields naturally adjacency limitation ● Adjacencies are between: – MPR and MPR-selectors (MPR links) ● Some routers form adjacencies with every neighbor – Hybrid routers (with both traditional and MANET interfaces) ● Results in ”lossless” topology reduction Topology Reduction with MPR Links Adjacency Limitation

7. INRIA Hitachi Ecole Polytechnique 7 MPR links guarantee shortest paths DSDS Case 1 Case 2 MANET-OSPF 2-WAY link Adjacency MANET source hop may be 2-WAY

8. INRIA Hitachi Ecole Polytechnique 8 OSPF Heterogeneous Topologies D S D S MANET-OSPF Case 1 Case 2 paths to/through a MANET: made of adjacencies the best paths (shortest) 2-WAY link Adjacency OSPF

9. INRIA Hitachi Ecole Polytechnique 9 Path costs are minimal D S no out-of-track forwarding MANET-OSPF 2-WAY link Adjacency 1 OSPF 1 1 1 1 1 1

10. INRIA Hitachi Ecole Polytechnique 10 MPR Links Topology Reduction Evaluation number of links in advertized topology MANET LSUpdate overhead (number of advertized links per minute) Full topology MPR-OSPF Full topology MPR-OSPF Unit Disk Graph simulations: speed 60 mph, radio range 1 mile, 40 - 100 routers

11. INRIA Hitachi Ecole Polytechnique 11 Flooding Optimization with MPR ● MPR selection can also be used to optimize flooding ● Only MPRs retransmit – The whole network is covered – The number of retransmitters is drastically reduced S MPR S

12. INRIA Hitachi Ecole Polytechnique 12 Flooding Optimization with MPR Number of retransmitters to complete flooding Traditional flooding MPR flooding Unit Disk Graph simulations: 2x2 miles, radio range 1 mile, 40 - 100 routers

13. INRIA Hitachi Ecole Polytechnique 13 OSPF MPR Extension in a Nutshell MPR is validated to be simple and efficient by manet-wg Drastic overhead reduction (topology × flooding) No loss in connectivity Guaranteed no route-stretch Simple leverage of existing code base, extensible Performs well in all cases (including high mobility) MPR information is signalled only on MANET interface, with HELLO packets + appended LLS information.

14. INRIA Hitachi Ecole Polytechnique 14 Next Step ● MPR extension must be evaluated for OSPF on MANETs