Real-World Performance of current Mesh Protocols in a small-scale - PowerPoint PPT Presentation

Real-World Performance of current Mesh Protocols in a small-scale Dual-Radio Multi-Link Environment Karl Jonas Manuel Hachtkemper Michael Rademacher manuel.hachtkemper@inf.h-brs.de karl.jonas@h-brs.de michael.rademacher@h-brs.de 22. ITG Fachtagung Mobilkommunikation May 10, 2017 1

Table of Contents Introduction and motivation Dual-radio mesh networks Setups Test procedure Results Conclusion 2

Introduction and motivation - Internet in rural areas � Using a cost-efficent technology to bring connectivity to rural areas. ◮ Local distribution of connectivity is the next step. ◮ Dual-Radio WiFi Mesh Networks are (among others) one option: - Which mesh protocol to prefer? [Babel, B.A.T.M.A.N. V, BMX7, OLSRv2] - Which dual-radio setup to prefer? Access: Internet WiFi Dual-Radio Mesh Core PSTN Network Access Backhaul: WiFi Long-Distance Multi-Radio Mesh 3

Dual-radio mesh networks 1 Wireless router Wireless client 2 3 Channel A Channel B Ethernet Internet 4 5 Example of a wireless mesh network with two radios attached to each router. 4

Setup 1 Wireless router Wireless client Channel A Ethernet Tra ଏ c source Setup 1 for the experiments: One radio for everything on one channel; second radio unused. 5

Setup 2 Wireless router Wireless client Channel A Channel B Ethernet Tra ଏ c source Setup 2 for the experiments: One radio for the mesh on one channel and another radio with a different channel for the clients. 6

Setup 3 Wireless router Wireless client Channel A Channel B Ethernet Tra ଏ c source Setup 3 for the experiments: One channel for both mesh network and clients and a second radio with another channel for the mesh network. 7

Preliminary considerations for the experiments ◮ Has the system to “warm-up”? For how long? ◮ How to generate traffic? And for how long? ◮ How to get the measurement reproducible? ◮ How to prevent that different measurements affect each other? 8

Length of measurements 50000 45000 data rate (kbit/s) 40000 35000 30000 25000 20000 0 100 200 300 400 500 600 time (s) measurement 1 measurement 5 measurement 9 measurement 2 measurement 6 measurement 10 measurement 3 measurement 7 measurement 4 measurement 8 Development of the data rate over a period of 10 minutes. Intermediate values were taken every 10 seconds and always the overall data rate since the start is calculated. (Babel, Setup 3) 9

Length of measurements Percentage deviation: rel _ dev x 10 − x 20 = x 20 − x 10 ∗ 100 x 10 1.0 Deviation in reference to previous value ● ● 95% confidence interval ● 0.5 mean deviation (%) ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 0.0 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● Confidence interval: −0.5 s [ x ± t n − 1 , 1 − α/ 2 ∗ √ n ] −1.0 0 100 200 300 400 500 600 α = confidence level time (s) n = number of observations Development of the data rate over a period of 10 minutes. The mean percentage deviation in reference � n � 1 to previous mean value is shown. (Babel, Setup 3) � � ( x i − x ) 2 s = � n − 1 i =1 10

Reproducibility / test procedure C4 C5 1m 1m 1m 1m 1m C3 C6 R2 R3 2m 1m 1m Wireless router 1m 1m Wireless client C2 R1 R4 C1 1m Tra ✁ c source C1 Picture of the setup (in an underground Physical placement of nodes. parking lot). 11

Hypothesis 1. Using dual-radio routers compared to single-radio routers doubles the achievable data rate for clients. ◮ 2 channels = 2 * bandwidth = 2 * data rate 2. The mesh routing protocol influences the results, although all routers are direct neighbors. ◮ Different overhead for each protocol 3. Using both channels for the mesh (Setup 3) is worse than having a dedicated channel for all clients and one for the mesh (Setup 2). ◮ More mesh protocol overhead ◮ The routing protocol may use the channel which is occupied by the clients 12

Results: Single channel (S1) vs dual channel (S2) 40000 35000 data rate (kbit/s) 30000 25000 20000 15000 B B B B B B O O a a . . M M L L A A b b X X S S . . e e T T R R 7 7 l l . . M M v v S S S S 2 2 . . 1 2 1 2 A A S S . . N N 1 2 . . V V S S 1 2 Box plot of the results of Setup 1 and 2. Each box plot consists of ten measurements, where each data point is the sum of the six client results. 13

Dedicated access (S2) vs mixed mesh/access (S3) 40000 38000 36000 data rate (kbit/s) 34000 32000 30000 28000 26000 B B B B B B O O a a . . M M L L A A b b X X S S . . e e T T R R 7 7 l l . . M M v v S S S S 2 2 . . 2 3 2 3 A A S S . . N N 2 3 . . V V S S 2 3 Box plot of the results of Setup 2 and 3. Each box plot consists of ten measurements, where each data point is the sum of the six client results. 14

Conclusion ◮ Mesh protocols have specific features for multi-radio networks. ◮ Expected: Dual-radio routers = 2 * data rate of single-radio routers. ◮ Not expected: Different mesh protocols lead to similar results (in our scenario). ◮ Not expected: Using both radios within the mesh is equally good and should be preferred (in our scenario). ◮ The protocol overhead is negligible in small networks 15

Thank you very much! Are there any questions? Manuel Hachtkemper Karl Jonas Michael Rademacher manuel.hachtkemper@inf.h-brs.de michael.rademacher@h-brs.de karl.jonas@h-brs.de 16

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