Protcols for Highly-Dynamic Airborne NetworksEgemen K. Çetinkaya, Justin P. Rohrer, Abdul Jabbar, Mohammed J.F. Alenazi, Dongsheng Zhang, Dan S. Broyles, Kamakshi Sirisha Pathapati, Hemanth Narra, Kevin Peters, Santosh Ajith Gogi, and James P.G. Sterbenz

Department of Electrical Engineering and Computer ScienceUniversity of Kansas

1Presented by Curtis Kelsey

Overview• Introduction• Motivation• ANTP• AeroTP• AeroNP• AeroRP• AeroGW

• Simulation Results• Conclusions• Observations• References

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Introduction• Airborne network structure• Predecessors to ANTP• TCP/IP (UDP)

• 40 byte packet overhead• Static routing• Transport assumes stable path• No explicit cross-layer info exchange

• Mobile Ad-Hoc Network (MANET)• Routing relies on non-geographic based

links• Space Communications Protocol

Standards (SCPS-TP)3

Dynamic airborne environment

Introduction• Challenges• Limited power (limits range) • Limited RF-spectrum • Intermittent connectivity• Mobility (Speeds up to Mach 3.5)• Data corruption & loss

• TCP limits• Assumes all loss is congestion• Handshaking connection setup• Slow-start algorithm

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Motivation• Integrated Networked

Enhanced Telemetry (iNET) program identified a set of needs

• Predecessors do not serve this domain adequately

5Link Stability Analysis

Airborne network protocols

ANTP• Consists of 4 protocols• Aeronautical Transport

Protocol (AeroTP)• Aeronautical Network

Protocol (AeroNP)• Aeronautical Routing

Protocol (AeroRP)• Aeronautical Gateway

(AeroGW)• Why? Small contact duration

between two TAs.

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System architecture

AeroTP• Handshake-free connection setup• Transmit peak-rate immediately• Reduced ACK usage; Selective

Negative ACK (SNACK)• Header compression• Relay nodes buffer data for

retransmit• Connection state info memory• Modes• Reliable (fully TCP compatible)• Nearly-reliable• Quasi-reliable• Best-effort connections• Best-effort datagrams (fully UDP

compatible)7

Data Segment Structure

MACK Segment Structure

AeroTP

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AeroTP

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• Control messages used for opening/closing connection• ASYN, ASYNACK,AFIN,

AFINACK• Opportunistic connection

establishment• Data & control overlap

State Transition Definitions

Connection Management

State Transition Diagram

AeroNP• IP-compatible network protocol• Replicates IP services• Provides• QoS – 4 levels

• AeroRP packets are classed the highest always• C2 given priority over application data

• Flow control• Implemented by a cross-layering mechanism with the iNET TDMA MAC layer

• Error detection• Corruption Indicator- header error check- cyclic redundancy code (HEC-CRC)

• Congestion Indicator (CI)• Specifies node congestion (defers packets from being forwarded)

• Geological Information• AN geological information (extended header)• Else, basic header

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AeroNP Packet Structure

AeroRP• Geographic routing protocol• Per-hop routing decisions• GS Updates• Additional mechanism for neighbor discovery• AN topology info or link info broadcast to other Ans• GSTopology/GSLink advertisements

• Operation Modes• Ferrying• Buffer• Drop

• Promiscuous• Beacon• Beaconless

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AeroRP• Phase 1• Neighbor discovery

• Active snooping• Beacon mode• GS Updates

• Phase 2• Data forwarding

• Determine next hop from topology table• Use time-to-intercept (TTI) metric• delta d = Euclidean distance• R = common transmission range• sd = recorded speed

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AeroGW• IP - AeroNP translation• TCP/UDP/RTP - AeroTP

splicing• Gateways are built into TAs

and GSs

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AeroGW

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Simulation Results• Simulations performed using

ns-3• 1MB of data transmitted• AeroTP• Selective-repeat ARQ used

for reliable mode• FEC used for quasi-reliable

mode

15AeroTP fully-reliable mode

Average goodput Average delay

Cumulative goodput Cumulative overhead

Cumulative goodput comparison

Simulation Results• AeroRP• Velocity 1200 m/s• Node density 5 to 60

16Ae

roRP

Res

ults

Effect of node density on PDR

Conclusions• Existing TCP/IP protocols are not suited for highly-dynamic

airborne networks

• Prediction of link availability provides significant improvements in end-to-end data delivery (AeroRP)

• Further testing required. Planned testing on radio-controlled aircraft.

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Presenter’s Observations• Degradation of redundancy = throughput improvements

• Introduction of spatial cues increases system knowledge/forcast capability

• Cross-layer communication reduces redundancy without reducing information

• Per node burden is increased/ more costly nodes

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References• (Primary Paper) Cetinkaya, E., & Rohrer, J. (2012). Protocols for highly-dynamic airborne

networks. Proceedings of the 18th annual international conference on Mobile computing and networking, 411–413. Retrieved from http://dl.acm.org/citation.cfm?id=2348597

• Narra, H., Cetinkaya, E., & Sterbenz, J. (2012). Performance analysis of AeroRP with ground station advertisements. Proceedings of the first ACM …, 43–47. Retrieved from http://dl.acm.org/ft_gateway.cfm?id=2248337&ftid=1233995&dwn=1&CFID=118936837&CFTOKEN=41922410

• Sterbenz, J., Pathapati, K., Nguyen, T., & Rohrer, J. (2011). Performance Analysis of the AeroTP Transport Protocol for Highly-Dynamic Airborne Telemetry Networks. Retrieved from http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA544743

• J. P. Rohrer, E. Perrins, and J. P. G. Sterbenz. End-to-end disruption-tolerant transport protocol issues and design for airborne telemetry networks. In Proceedings of the International Telemetering Conference (ITC), San Diego, CA, October 2008

• A. Jabbar, E. Perrins, and J. P. G. Sterbenz. A cross-layered protocol architecture for highly-dynamic multihop airborne telemetry networks. In Proceedings of the International Telemetering Conference (ITC), San Diego, CA, October 2008.

• E. K. ¸Cetinkaya and J. P. G. Sterbenz. Aeronautical Gateways: Supporting TCP/IP-based Devices and Applications over Modern Telemetry Networks. In Proceedings of the International Telemetering Conference (ITC), Las Vegas, NV, October 2009.

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Summary• Introduction• Motivation• ANTP• AeroTP• AeroNP• AeroRP• AeroGW

• Simulation Results• Conclusions• Observations• References

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Questions?

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