PLASMA: A New Routing Paradigm for Wireless Multihop Networks R. Laufer 1 P. Velloso 2 L. Vieira 3 L. Kleinrock 1 1 University of California, Los Angeles 2 Universidade Federal Fluminense Los Angeles, USA Niteroi, Brazil 3 Universidade Federal de Minas Gerais Belo Horizonte, Brazil

Multiple Gateways  Total load directed to the lowest-cost gateway  Current routing models limited to unicast delivery  Prevents simultaneous use of multiple gateways  Fairness and under-utilization issues Internet 2 Gateway

Our Contributions  New routing paradigm for wireless networks  Internet traffic can be delivered to any gateway  Network decides both the path and gateway on the fly  Optimal polynomial-time routing algorithm  Load balancing  Load split among different gateways via anycasting  Technique for different gateway uplink bandwidths 3

Anycast Forwarding  Packet broadcast to multiple nodes simultaneously  High chance of at least one node receiving it  Node with the lowest cost forwards it on  Coordination with overhearing or ACK channels Time SNIR Time SNIR Time SNIR 4

Plasma Routing  Every node forwards packets to a set of nodes  Directed acyclic graph (DAG) to the gateways  This DAG is called a plasma path 5 s d1d1 d2d2 d3d3

Plasma Routing Challenges  Forwarding set selection  Few neighbors: lower receiver diversity  Many neighbors: potentially higher costs  Rate selection  Lower rates: lower loss, longer range, less hops  Higher rates: higher loss, shorter range, more hops  Gateway set selection  More gateways do not always reduce the routing cost  How to choose the optimal tradeoff point? 6

Plasma Path Cost  What is the cost of a plasma path?  Similar to the cost in anypath routing*  Composed of two different components  Hyperlink cost  Remaining cost d iJ (r) DJ(r)DJ(r) DJ(r)DJ(r) i J 7 d1d1 d2d2 * R. Laufer et al. “Multirate Anypath Routing in Wireless Mesh Networks”, INFOCOM’09 R. Laufer et al., “Polynomial-Time Algorithms for Multirate Anypath Routing in Wireless Multihop Networks”, IEEE/ACM ToN

Plasma Cost Example  Cost calculation 8 1.4? i d1d1 d2d d3d3 J.4

Plasma Cost Calculation  Is it better to use more nodes/gateways? No!  Additional node always decreases hyperlink cost  May increase remaining cost 9 1.4? i d1d1 d2d d3d3 J’.4

Plasma Routing  Distributed and optimal routing algorithm  Generalization of the Bellman-Ford algorithm  Run time of 10 s d1d1 d2d2 d3d ∞ ∞ 0 ∞ ∞ 0 0 ∞ ∞ ∞ ∞

Load Balancing  Plasma already has some intrinsic load balancing  Gateway d 1 receives of the traffic  Gateway d 2 receives of the traffic  In general, a gateway d receives  Load depends on delivery ratios i j k l d1d1 d2d2 11

 Each gateway d assigned a non-zero cost  Higher cost has a back-pressure effect Load Balancing s d1d1 d2d2 d3d

 IEEE a  Path-loss and SNIR models for the PHY layer  500x500 m 2 grid topology with 11x11 nodes Simulation Scenario 13

Plasma Throughput 14 98% 2.9x 5.6x

Plasma End-to-End Delay x 2.2x 5.4x

Different Uplink Bandwidths 16 1 Mbps

Conclusions  Plasma routing  Generalization of anypath routing to anycast delivery  Optimal polynomial-time distributed routing algorithm  Load balancing for different uplink bandwidths  Simulation results  98% throughput gain and 2.2x delay decrease  Load balancing gives additional 63% throughput gain 17

PLASMA: A New Routing Paradigm for Wireless Multihop Networks R. Laufer 1 P. Velloso 2 L. Vieira 3 L. Kleinrock 1 1 University of California, Los Angeles 2 Universidade Federal Fluminense Los Angeles, USA Niteroi, Brazil 3 Universidade Federal de Minas Gerais Belo Horizonte, Brazil