[tcpm] Review: draft-ietf-tcpm-early-rexmt-01

Alexander Zimmermann <alexander.zimmermann@nets.rwth-aachen.de> Fri, 14 August 2009 10:09 UTC

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From: Alexander Zimmermann <alexander.zimmermann@nets.rwth-aachen.de>
To: Mark Allman <mallman@icir.org>
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Date: Fri, 14 Aug 2009 12:06:58 +0200
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Subject: [tcpm] Review: draft-ietf-tcpm-early-rexmt-01
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Hi Mark, hi TCPM

as requested at the last TCPM meeting in Stockholm that we need some  
reviews for Early Retransmit (draft-ietf-tcpm-early-rexmt-01), here  
are some comments from me:

*** Content

* First of all I like the draft. Short and easy. There exist a byte- 
based and a packet-based version. In both cases there is also a SACK  
and a non-SACK version described.

* The "entry point" of the algorithm could be better described. For  
example lets begin paragraph 2 in section 2.1 as follows: When an  
acknowledgment arrives at the sender, the sender ...

* What about RFC4653 - Improving the Robustness of TCP to Non- 
Congestion Events? Is Early Retransmit compatible to RFC4653? At first  
glance I think yes, when we define a priority which algo should alter  

*** Minor comments

* Section 1, para 3: s/Small windows/Small congestion windows/

* Section 1, last para: Explanation of the difference between Limited  
Transmit and Early Retransmit. Maybe we can put here a pointer to the  
aforementioned case why a CWND can be small. For example (last  
sentence): The "Early Retransmit" mechanism outlined in this document  
covers the case when previously unsent data is not available (case 2)  
for transmission or cannot be transmitted due to an advertised window  
limitation (case 1).

* Check nits: http://tools.ietf.org/idnits?url=http://tools.ietf.org/id/draft-ietf-tcpm-early-rexmt-01.txt 
. Broken references and so on.

*** Misspellings

* Consistent quotation marks: Line 94/95 - s/``Fast Retransmit''/"Fast  

* Ref [RFC2018], line 440: s/Acknowledgement/Acknowledgment/g :-)


// Dipl.-Inform. Alexander Zimmermann
// Department of Computer Science, Informatik 4
// RWTH Aachen University
// Ahornstr. 55, 52056 Aachen, Germany
// phone: (49-241) 80-21422, fax: (49-241) 80-22220
// email: zimmermann@cs.rwth-aachen.de
// web: http://www.umic-mesh.net