[ndnSIM] leaky bucket start time

[Yaogong Wang]

I see your point. Such kind of synchronization could lead to some
simulation artifacts. But I believe this should be taken care of by the
users. They should be aware of this (such synchronization problems could
happen in any simulator) and incur some randomness in their simulation
setup.

My concern with the current implementation is that the leak start time is
randomly picked between 0s and 1s. It is fairly possible that lots of
packets have already been sent before the leak start time. These packets
may get stuck in the network because the bucket didn't start leaking when
it should have. This might not be a big issue most of the time but did
cause me some headache in some particular setup.

Thanks,
Yaogong

On Wed, Feb 13, 2013 at 1:57 PM, Alex Afanasyev <
alexander.afanasyev at ucla.edu> wrote:

> True. But if two guys receive a packet at the same time (can happen in
> some simple topologies), they would start leaking at the same time,
> resulting in synchronized decision, which may lead to unexpected results (I
> had them with simplistic topologies).
>
> ---
> Alex
>
> On Feb 13, 2013, at 10:39 AM, Yaogong Wang <ywang15 at ncsu.edu> wrote:
>
> It doesn't seem to make much sense. The bucket anyway starts out as empty.
> Leaking won't really happen until someone calls BorrowLimit().
>
> Yaogong
>
> On Wed, Feb 13, 2013 at 1:17 PM, Alex Afanasyev <
> alexander.afanasyev at ucla.edu> wrote:
>
>> Hi!
>>
>> I've put it there to ensure that nodes don't make a synchronized leaks of
>> buckets, which impossible in real life, but could happen in some cases in
>> the simulations.
>>
>> ---
>> Alex
>>
>>
>> On Feb 13, 2013, at 9:45 AM, Yaogong Wang <ywang15 at ncsu.edu> wrote:
>>
>> > Hi,
>> >
>> > I'm curious why do we randomize the leak start time in
>> LimitsRate::NotifyNewAggregate() under untils/ndn-limits-rate.cc. Why can't
>> we just start leaking at 0.0?
>> >
>> > Thanks,
>> > Yaogong
>>
>
>
>
> --
> ============================
> Yaogong Wang, PhD Candidate
> Department of Computer Science
> North Carolina State University
> http://www4.ncsu.edu/~ywang15/
> ============================
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>


-- 
============================
Yaogong Wang, PhD Candidate
Department of Computer Science
North Carolina State University
http://www4.ncsu.edu/~ywang15/
============================
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