[Iccrg] Looking for reviewer for draft-ietf-ledbat-congestion-06

[Michael Welzl]

thank you!

I'm cc'ing ledbat in my answer.

Cheers,
Michael


On Jun 12, 2011, at 8:53 AM, Lisong Xu wrote:

> Hi Michael,
>
> Below are my comments after reading the draft.
> Thanks
> Lisong
>
>
> **** Section 3.1 ****
> First sentence: "a loss occurs [RFC5681], which, in the absence of  
> any Active Queue Management (AQM) in the network, occurs only when  
> the queue at the bottleneck link on the end-to-end path overflows "
>
> Since a loss may occur due to link errors, such as fiber errors and  
> wireless errors, we may change the first sentence to
> "... (AQM) and link errors in the network,...."
>
> **** Section 3.3 ****
> The data type of each variable is not specified. Since some  
> variables must be signed variables, it is important to specify the  
> type of each variable in order to correctly implement the algorithm.
>
> For example, tcp_time_stamp is an unsigned int, so local_timestamp  
> and remote_timestamp are also unsigned int.  But variable  
> acknowledgement.delay should be a signed int, since local_timestamp- 
> remote_timestamp may be negative.
>
> **** Section 3.4.2 ****
> "a LEDBAT sender stores BASE_HISTORY+1 separate minima- one each for  
> the last BASE_HISTORY minutes, and one for the running current  
> minute."
>
> But the update_current_delay(delay) code maintains only BASE_HISTORY  
> minima. So the above sentence should be changed to
> "a LEDBAT sender stores BASE_HISTORY separate minima- one each for  
> the last BASE_HISTORY-1 minutes, and one for the running current  
> minute."
>
> **** Section 3.5 ****
> "we recommend that the sender SHOULD use at least 4 samples in each  
> RTT. Thus, CURRENT_FILTER SHOULD be at least 4, and limited such  
> that no samples in list are older than an RTT in the
> past."
>
> But what if cwnd is less than 4? In this case, there are less than 4  
> samples in each RTT.
>
>
> **** General *****
>
> It is not clear what the relation between cwnd and flightsize is. Is  
> flightsize always the same as cwnd, or could be less than cwnd? When  
> is flightsize less than cwnd?
>
>
> On 6/5/2011 12:38 AM, Michael Welzl wrote:
>> Hi,
>>
>> We're urgently looking for a volunteer to review
>> draft-ietf-ledbat-congestion-06:
>> http://tools.ietf.org/html/draft-ietf-ledbat-congestion-06
>> which is currently in Last Call, ending in less than two weeks (15  
>> June).
>>
>> If anyone here is willing to do a review, please drop Murari and me a
>> note ASAP!
>>
>> Thanks,
>> Michael
>>
>>
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>>
>
> -- 
> Lisong Xu, Associate Professor
> Computer Science & Engineering
> University of Nebraska-Lincoln
> http://cse.unl.edu/~xu