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Nguyen, Rohrer, Sterbenz ITTC ResTP A Transport Protocol for Future Internet Resilience

28 March 2015

Anh Nguyen, Justin P. Rohrer, and James P.G. Sterbenz

Department of Electrical Engineering & Computer Science Information Technology & Telecommunications Research Center

The University of Kansas

annguyen|rohrej|jpgs@ittc.ku.edu

© 2015 Nguyen!

Nguyen, Rohrer, Sterbenz ITTC

ResTP Outline

•  Introduction and motivation •  Related work •  ResTP architecture •  AeroTP – subset of ResTP •  Conclusions and future work

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ResTP Introduction and Motivation

•  Introduction and motivation •  Related work •  ResTP architecture •  AeroTP - subset of ResTP •  Conclusions and future work

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Introduction and Motivation Issues in TCP

•  TCP & UDP –  dominant transport protocols in the Global Internet

•  Fragility in performance of network applications –  end-user experience far from optimal

•  emerging of new applications & use paradigms –  mobile ad-hoc networks (MANETs) –  disruption- and delay-tolerant networks (DTNs) –  wireless mesh networks (WMNs) –  wireless sensor networks (WSNs)

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Introduction and Motivation Issues in TCP

•  TCP limitations due to assumptions behind its design –  designed for wired networks

•  wireless networks exhibit higher BER

–  assume stable E2E path •  challenged networks frequently partitioned

–  low delay underlying network •  high latency

–  increase probability of multiple losses –  delay TCP reaction to changing network conditions

–  assume single best path between hosts •  take advantage of multiple paths essential for resilience

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Introduction and Motivation TCP Improvement Approaches

•  Modify TCP –  TCP variants: Westwood(+), Peach, Illinois –  temporary solution addressing a specific issue

•  Extend TCP –  normally accomplished through TCP options –  40-byte for options limit extensions

•  TCP SACK with only 3-available SACK blocks

•  Develop new transport-layer protocol

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Introduction and Motivation ResTP

•  ResTP –  Resilient Transport Protocol –  designed based on ResiliNets framework

•  broad definition of resilience •  cover multiple disciplines

–  survivability, fault-, disruption-, and traffic- tolerance –  dependability (reliability & availability), security, performability –  robustness, complexity

–  first protocol designed with all aspects of resilience

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Introduction and Motivation ResTP

•  ResTP –  resilient (delay/disruption tolerant), composable, multipath –  support various application classes across diff. networks –  provide multiple transport-layer services

•  multiplexing/demultiplexing, flow management •  error control, transmission control (flow/congestion) •  multipath spreading •  each service comprised of multiple mechanisms

–  support cross-layering •  behavior tuned by applications •  operation influence/adjusted based on feedback from network

–  capable of taking advantage of multiple diverse paths

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ResTP Related Work

•  Introduction and motivation •  Related work •  ResTP architecture •  AeroTP – subset of ResTP •  Conclusions and future work

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ResTP Related Work

•  Challenged or intermittently-connected networks –  DTN Architecture

•  Bundle Protocol •  TCP Convergence Layer (TCPCL) •  Licklider Transmission Protocol (LTP)

–  SCPS-TP for space communications •  different mechanisms for different sources of loss •  new loss-tolerant header compression •  hybrid SNACK acknowledgement option

–  supported by ResTP

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ResTP Related Work

•  Others: –  TP++ composability –  Stream Control Transmission Protocol (SCTP) –  Multipath TCP (MPTCP)

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ResTP ResTP Architecture

•  Introduction and motivation •  Related work •  ResTP architecture

–  ResTP cross-layering in the protocol stack –  ResTP header –  ResTP supported services

•  AeroTP – subset of ResTP •  Conclusions and future work

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ResTP Architecture ResTP Cross-Layering

•  Introduction and motivation •  Related work •  ResTP architecture

–  ResTP cross-layering in the protocol stack –  ResTP header –  ResTP supported services

•  AeroTP – subset of ResTP •  Conclusions and future work

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ResTP ResTP Cross-Layering

•  ResTP –  receive service spec & threat model

•  from application

–  determine/adapt •  mechanisms & resilient services •  based on app needs

–  request GeoDivRP •  calculate k d-geodiverse paths •  satisfy [h, t] stretch and skew

–  establish multipath E2E flow •  using k d-geodiverse paths •  actual data transfer

28 March 2015

path char!

dials!knobs!

{ss, tm}

GeoDivRP!

ResTP!

App!

{k,d,[h,t ]}

K32

D74

D43

D32

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ResTP Architecture ResTP Header

•  Introduction and motivation •  Related work •  ResTP architecture

–  ResTP cross-layering in the protocol stack –  ResTP header –  ResTP supported services

•  AeroTP – subset of ResTP •  Conclusions and future work

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ResTP Architecture ResTP Header

•  Mode: transfer mode: flow + error control –  ERA (multipath erasure coding), ARQ, FEC, (HARQ) CRC,

CON (connection), OPT (opportunistic), CT (custody xfer) •  MSB to LSB

–  fully reliable: 0x2C (ARQ, CRC, CON bits are set)

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r!

sequence number!timestamp!

mode! payload length!

destination port!source port!

payload!

flags!ECN!

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ResTP Architecture ResTP Supported Services

•  Introduction and motivation •  Related work •  ResTP architecture

–  ResTP cross-layering in the protocol stack –  ResTP header –  ResTP supported services

•  AeroTP – subset of ResTP •  Conclusions and future work

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ResTP Supported Services Flow Management

•  Connection oriented (CON=1) –  3-way handshake (TCP-like) –  opportunistic (OPT=1)

•  data overlap setup messages

–  E2E ACKs (CT=0) vs. e2e ACKs with custody xfer (CT=1)

•  Connectionless (CON=0) –  individual datagrams (UDP-like)

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ResTP Supported Services Error Control

•  ARQ (automatic repeat request) (ARQ=1  &  FEC=0) –  for reliable data transfer –  alternative ACK schemes

•  ACK, MACK (Multiple), NACK, SACK, SNACK

•  Adaptive FEC (forward error correction) (ARQ=0  &  FEC=1) –  for quasi-reliable data transfer

•  HARQ (Hybrid ARQ = ARQ + FEC) (ARQ=1  &  FEC=1)  –  reliable data transfer with E2E FEC

•  No error control (ARQ=0  &  FEC=0)  –  for highly loss tolerant applications

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ResTP Supported Services Transfer Modes

•  Combination of flow management & error control –  fully reliable: 3-way handshake & E2E ACKs –  nearly reliable: custody transfer at GWs with E2E ACKs –  quasi reliable: E2E FEC to achieve statistical reliability –  unreliable connection: connection oriented best effort –  unreliable datagram: connectionless best effort

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ResTP Supported Services Multipath Spreading

•  Data transfer using multiple physical paths –  paths selected are geo-diverse

•  GeoDivRP •  multihomed hosts

–  support multiple modes •  actively spreading data over all selected paths •  use one active, others hot standby for rapid failover

–  selection of modes based on •  path attribute, application type, mission requirements

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ResTP AeroTP – subset of ResTP

•  Introduction and motivation •  Related work •  ResTP architecture •  AeroTP – subset of ResTP •  Conclusions and future work

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ResTP AeroTP – subset of ResTP

•  AeroTP (Aeronautical Transport Protocol) –  domain-specific –  highly-dynamic airborne telemetry network environment –  opportunistic flow management and 5 transfer modes –  simulations show better performance than TCP

•  in ns-3 open-source simulator

•  [TAES 2011, MILCOM 2012]

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ResTP AeroTP vs. TCP: Average Throughput

•  TCP & AeroTP-ARQ –  back off with BER

•  AeroTP-ARQ –  outperforms TCP

•  significantly

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ResTP AeroTP vs. TCP: Average Delay

•  TCP E2E delay –  doubles at BER = 10-4

•  AeroTP-ARQ E2E delay –  small increase

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ResTP AeroTP vs. TCP: Cumulative Overhead

•  AeroTP-ARQ –  much less overhead than TCP

•  AeroTP-FEC –  significant overhead

•  delay unaffected

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ResTP AeroTP vs. TCP: Data Delivered

•  AeroTP-ARQ –  delivers nearly all data with high BER

•  AeroTP-FEC –  less losses

•  than TCP, UDP •  with high BER

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ResTP Conclusion and Future Work

•  Introduction and motivation •  Related work •  ResTP architecture •  AeroTP – subset of ResTP •  Conclusions and future work

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ResTP Conclusions & Future Work

•  Conclusions –  ResTP designed with

•  all resilient-related aspects considered •  assumption of challenged underlying network environments •  goal to support various application classes

•  Work in progress –  completing detailed design of ResTP

•  Future work –  implement ResTP in ns-3 –  analyze ResTP in comparison with TCP, SCPS-TP, MPTCP –  implement prototype

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References

1.  [Bhattacharjee-2006] B. Bhattacharjee, K. Calvert, J. Griffioen, N. Spring, and J. Sterbenz, “Postmodern internetwork architecture,” Information and Telecommunication Center, 2335 Irving Hill Road, Lawrence, KS 66045-7612, Technical Report ITTC-FY2006-TR-45030-01, February 2006

2.  [Rohrer-2009] Justin P. Rohrer, Ramya Naidu, and James P. G. Sterbenz. “Multipath at the transport layer: An end-to-end resilience mechanism”. In Proceedings of the IEEE/IFIP International Workshop on Reliable Networks Design and Modeling (RNDM), pages 1-7, St. Petersburg, Russia, October 2009.

3.  [Rohrer-2011] J. P. Rohrer, A. Jabbar, E. K. Centikaya, E. Perrins, and J.P. Sterbenz. “Highly-dynamic cross-layered aeronautical network architecture”. IEEE Trans. Aerospace and Electronic Systems, 47(4):2742—2765, October 2011.

4.  [Sterbenz-2012] J.P.G. Sterbenz, D. Hutchison, E.K. Centinkaya, A. Jabbar, J.P. Rohrer, M. Scholler, and P. Smith, “Redundancy, Diversity, and Connectivity to Achieve Multilevel Network Resilience, Survivability, and Disruption Tolerance (invited paper),” Springer Telecommunication Systems, 2012.

5.  [Yufei-2014] Yufei Cheng, and James P.G. Sterbenz, “GeoDivRP Routing with Path Jitter Requirement under Regional Challenges”, IEEE/IFIP Sixth International Workshop on Reliable Networks Design and Modeling (RNDM’14), Barcelona, Spain, November 2014

6.  [Ford-2013] A. Ford et al. “TCP Extensions for Multipath Operation with Multiple Addresses”. RFC 6824 (Experimental), Jan. 2013

7.  [Durst-1996] R. C. Durst, G. J. Miller, and E. J. Travis. “TCP Extensions for Space Communications”. In ACM MobiCom ’96, pages 15—26, New York, NY, USA, November 1996. ACM Press.

8.  [Feldmeier-1993] D. Feldmeier. “An Overview of the TP++ Transport Protocol Project”. In A. N. Tantawy, editor, High Performance Networks: Frontiers and Experience, chapter 8. Kluwer, Boston, MA, USA, 1993.

9.  [Rohrer-2012]J. P. Rohrer, K. S. Pathapati, T. A. N. Nguyen, and J. P. G. Sterbenz. “Opportunistic Transport for Disrupted Airborne Networks”. In IEEE MILCOM, pages 737—745, Orland, FL, November 2012.

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ResTP Questions?

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