Open Research Issues in Internet Congestion Control

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Open Research Issues in Internet Congestion
Control

• draft-irtf-iccrg-welzl-congestion-control-open-res
  earch-04
• Michael Welzl, Dimitri Papadimitriou (eds.)
• Michael Scharf, Bob Briscoe

ICCRG Meeting Tokyo, JapanMay 2009
Michael Welzl http//www.welzl.atNetworks and
Distributed Systems group Department of
Informatics University of Oslo, Norway
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Introduction

• Intention show researchers that finding the
  ideal TCP is not the only open issue for
  congestion control
• This works I received a couple of emails from
  people (e.g. Ph.D. student) saying that the draft
  helps them
• Effort initiated during 1H07 (v00 in Jul.07 at
  IETF 69)
• Document starts with Global challenges
• General observations
• followed by Detailed challenges

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Global challenges

• Heterogeneity
• Various network environments, various protocols
  interacting, etc.
• Stability
• Fairness
• flow rate vs. cost fairness

4
Detailed challenges /1

• Network support
• Performance and robustness
• Granularity of network component functions
• Information acquisition
• Feedback signaling
• Corruption loss
• Packet Size

5
Detailed challenges /2

• Flow startup
• Multi-domain CC
• Transport of congestion signals
• Information exchange
• Pseudowires
• Precedence for elastic traffic

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Detailed challenges /3

• Misbehaving senders and receivers
• Others
• RTT estimation
• Malfunctioning devices
• Dependence on RTT
• CC in multi-layered networks
• Multipath e2e CC and TE
• ALGs and middleboxes

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Recent document changes

• Outcome (as outlined in the slides distributed
  during the IETF 73 ICCRG meeting) of an in-depth
  re-work of several sections
• Global challenges Stability (2.2), Fairness
  (2.3)
• Specific challenges
• Addition of dedicated challenge on flow startup
  (3.4)
• Reworked multi-domain congestion control (3.5)
• Addition of dedicated challenges for
• Multi-layer (6.8.4)
• Multi-path (6.8.5)
• ALG middleboxes (6.8.6)

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We believe that the document is ready for last
call

• Its about time for you to (re-)read it ... and
  comment