Interconnectivity Considerations and Usage Scenarios for ESS Mesh

1. Interconnectivity Considerations and Usage Scenarios for ESS Mesh Narasimha Chari (chari@tropos.com) Malik Audeh (malik.audeh@tropos.com) Tropos Networks San Mateo, CA Narasimha Chari, Malik Audeh - Tropos Networks

2. Purpose • Tropos Networks is supportive of the ESS Mesh Standards effort • We highlight the need for standardized interconnectivity • We compare and contrast the characteristics and functional requirements for a range of deployment scenarios • We present some observations about the state of mesh networking and on the feasibility of standardizing a routing protocol • We suggest a possible approach for the ESS Mesh Task Group to take Narasimha Chari, Malik Audeh - Tropos Networks

3. The need for standardized interconnectivity • Multiple vendors of mesh networking products already exist in the marketplace, serving different customer needs and providing solutions for different deployment environments • Specification of a standard way for mesh products from different vendors to interconnect is likely to fuel large-scale adoption of such systems • Interconnectivity across domain boundaries is likely to emerge as an important market requirement Narasimha Chari, Malik Audeh - Tropos Networks

4. Multiple deployment scenarios • Multiple deployment scenarios with differing functional requirements • Directional vs omni-directional meshes • Indoor vs outdoor • Fixed vs mobile • Fixed wireless vs mobile access • Infrastructure vs peer-to-peer • Public safety vs ISP vs wireless carriers Narasimha Chari, Malik Audeh - Tropos Networks

5. Directional or sectored Relatively static connectivity Clock synchronization may be necessary Interference less likely Longer-range links Omnidirectional Neighbor list is highly dynamic Clock synchronization may not be required Interference avoidance is an important requirement Shorter-range links with multipath and fading Directional vs Omnidirectional Narasimha Chari, Malik Audeh - Tropos Networks

6. Indoor Focus on higher data rates Peer-to-peer applications Symmetric power levels Backhaul more widely distributed and available Backhauls typically equivalent in capacity Indoor propagation – walls, ceilings, desks Outdoor Lower data rates with higher rates used opportunistically Client-server applications Highly asymmetric links, power levels Backhaul sparsely distributed, availability is challenging Heterogeneous capacities on backhaul Outdoor propagation – trees, trucks, buildings Indoor vs Outdoor Narasimha Chari, Malik Audeh - Tropos Networks

7. Fixed Nodes are static Optimum route choices favor stability Client devices not part of the mesh Application traffic flows are client-to-wired-server Multiple backhaul sources present Mobile Nodes can be moving at high speeds Optimal route choices favor quick adaptation No distinction between clients and nodes Application traffic flows are peer-to-peer Backhaul may or may not be present Fixed/Infrastructure vs Mobile/Peer-to-Peer Narasimha Chari, Malik Audeh - Tropos Networks

8. Mesh networking - a rapidly evolving area • Active area of research and development • Academic research – MIT RoofNet, CMU Monarch • Commercial innovation • Startups – Tropos, Mesh Networks, BelAir, Strix, Firetide, PacketHop, others • Established companies – Nortel, Intel, Motorola • Standards bodies (IETF MANET: AODV, DSR, DSDV, etc.) • Multiple approaches exist and more are being actively developed Narasimha Chari, Malik Audeh - Tropos Networks

9. Challenges with standardizing a routing protocol • Multiple deployment scenarios with differing functional requirements • No one-size-fits-all approach optimal across usage scenarios • Multiple approaches exist and more are being actively developed • Standardization of a single protocol may be premature and may stifle innovation in a rapidly evolving space Narasimha Chari, Malik Audeh - Tropos Networks

10. ESS Mesh – One Possibility • Common-denominator routing protocol • There is utility in standardizing a base protocol that addresses those requirements that are common across a set of usage scenarios • Likely to be suboptimal for a given usage scenario • The standard should provide flexibility to use custom protocols (out of the scope of the standard) to address the specific requirements of given usage scenarios Node-level interconnectivity Narasimha Chari, Malik Audeh - Tropos Networks

11. Next Steps • Prioritize deployment scenarios or usage models • Develop functional requirements for a base set of usage scenarios • Architect the system to retain flexibility and extensibility to adopt custom protocols tailored for specific usage models Narasimha Chari, Malik Audeh - Tropos Networks