[ndnSIM] ndnSIM Digest, Vol 6, Issue 35 How to get instant link load
ioannoa at scss.tcd.ie
ioannoa at scss.tcd.ie
Tue Jun 4 07:35:41 PDT 2013
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> Today's Topics:
>
> 1. Re: initial RTO value (Yaogong Wang)
> 2. Re: initial RTO value (Alex Afanasyev)
> 3. How to get instant link load (???)
> 4. Realistic but small topology for cache performance evaluation
> (Saeid Montazeri)
> 5. Re: How to get instant link load (Alex Afanasyev)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 28 May 2013 11:21:32 -0400
> From: Yaogong Wang <ywang15 at ncsu.edu>
> To: Alex Afanasyev <alexander.afanasyev at ucla.edu>
> Cc: yao hu <huyao0107 at gmail.com>, "ndnsim at lists.cs.ucla.edu"
> <ndnsim at lists.cs.ucla.edu>
> Subject: Re: [ndnSIM] initial RTO value
> Message-ID:
> <CA+y5TP0V_MgX67+m9iC9zae8n=4oOjOB14pZEoL-6P3mozx_fA at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Hi Alex,
>
> I believe the initial RTO should not be 200ms. According to the code, RTO
> is set to m_currentEstimatedRtt + 4 * m_variance bounded by minRto and
> maxRto. By default, m_currentEstimatedRtt is initially set to 1s (
> InitialEstimation) and m_variance to 0. Hence, the initial RTO should be
> 1s
> which is within minRto=200ms and maxRto=200s.
>
> The current code does set initial RTO to 200ms due to a bug that sets
> m_currentEstimatedRtt to 0 initially. I have reported the bug here:
> https://github.com/NDN-Routing/ndnSIM/issues/40
>
> Thanks,
> Yaogong
>
>
> On Wed, May 22, 2013 at 4:40 PM, Alex Afanasyev <
> alexander.afanasyev at ucla.edu> wrote:
>
>> Hi huyao,
>>
>> Yes. There is an initial RTO value and it is 200ms. You can control
>> this
>> value by setting "ns3::ndn::RttEstimator::MinRTO" value. ndnSIM uses a
>> modified version of RTT estimator, originally in Internet module:
>> https://github.com/NDN-Routing/ndnSIM/blob/master/utils/ndn-rtt-estimator.cc
>> .
>>
>> --
>> Alex
>>
>> On May 22, 2013, at 10:52 AM, yao hu <huyao0107 at gmail.com> wrote:
>>
>> Hi Alex,
>>
>> Is there a default initial RTO value for consumer node? RTO should be
>> calculated based on the observed RTT samples, but how about the first
>> Interest timeout for some reason? If there is a default initial value,
>> is
>> it 200ms?
>>
>> Thanks for your explanation~
>>
>> Regards,
>> huyao
>>
>>
>> _______________________________________________
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>>
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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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> ------------------------------
>
> Message: 2
> Date: Tue, 28 May 2013 11:11:41 -0700
> From: Alex Afanasyev <alexander.afanasyev at ucla.edu>
> To: Yaogong Wang <ywang15 at ncsu.edu>
> Cc: yao hu <huyao0107 at gmail.com>, "ndnsim at lists.cs.ucla.edu"
> <ndnsim at lists.cs.ucla.edu>
> Subject: Re: [ndnSIM] initial RTO value
> Message-ID: <D97AB172-5DA1-4938-9A63-976CFBBECE24 at ucla.edu>
> Content-Type: text/plain; charset="us-ascii"
>
> Hi Yaogong,
>
> Thanks for opening an issue and finding the problem! I just incorporated
> your commit that fixes the incorrect initialization of attributes.
>
> As of now, the initial RTO is 1 second, and later cannot become smaller
> than the minimum, which is by default set to 200ms.
>
> ---
> Alex
>
> On May 28, 2013, at 8:21 AM, Yaogong Wang <ywang15 at ncsu.edu> wrote:
>
>> Hi Alex,
>>
>> I believe the initial RTO should not be 200ms. According to the code,
>> RTO is set to m_currentEstimatedRtt + 4 * m_variance bounded by minRto
>> and maxRto. By default, m_currentEstimatedRtt is initially set to 1s
>> (InitialEstimation) and m_variance to 0. Hence, the initial RTO should
>> be 1s which is within minRto=200ms and maxRto=200s.
>>
>> The current code does set initial RTO to 200ms due to a bug that sets
>> m_currentEstimatedRtt to 0 initially. I have reported the bug here:
>> https://github.com/NDN-Routing/ndnSIM/issues/40
>>
>> Thanks,
>> Yaogong
>>
>>
>> On Wed, May 22, 2013 at 4:40 PM, Alex Afanasyev
>> <alexander.afanasyev at ucla.edu> wrote:
>> Hi huyao,
>>
>> Yes. There is an initial RTO value and it is 200ms. You can control
>> this value by setting "ns3::ndn::RttEstimator::MinRTO" value. ndnSIM
>> uses a modified version of RTT estimator, originally in Internet module:
>> https://github.com/NDN-Routing/ndnSIM/blob/master/utils/ndn-rtt-estimator.cc.
>>
>> --
>> Alex
>>
>> On May 22, 2013, at 10:52 AM, yao hu <huyao0107 at gmail.com> wrote:
>>
>>> Hi Alex,
>>>
>>> Is there a default initial RTO value for consumer node? RTO should be
>>> calculated based on the observed RTT samples, but how about the first
>>> Interest timeout for some reason? If there is a default initial value,
>>> is it 200ms?
>>>
>>> Thanks for your explanation~
>>>
>>> Regards,
>>> huyao
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> ndnSIM mailing list
>>> ndnSIM at lists.cs.ucla.edu
>>> http://www.lists.cs.ucla.edu/mailman/listinfo/ndnsim
>>
>>
>> _______________________________________________
>> ndnSIM mailing list
>> ndnSIM at lists.cs.ucla.edu
>> http://www.lists.cs.ucla.edu/mailman/listinfo/ndnsim
>>
>>
>>
>>
>> --
>> ============================
>> Yaogong Wang, PhD Candidate
>> Department of Computer Science
>> North Carolina State University
>> http://www4.ncsu.edu/~ywang15/
>> ============================
>
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> ------------------------------
>
> Message: 3
> Date: Wed, 29 May 2013 09:49:45 +0800 (CST)
> From: ??? <blindeafer at 163.com>
> To: ndnsim at lists.cs.ucla.edu
> Subject: [ndnSIM] How to get instant link load
> Message-ID: <5cf55571.2c78.13eedfa04a0.Coremail.blindeafer at 163.com>
> Content-Type: text/plain; charset="gbk"
>
> Hi all,
> I have an idea about cache scheme.In this scheme,I want to get the instant
> incoming link load everytime a contentobject come into a node and the
> outgoing link load(s) according to PIT entry if the contentobject is
> matched in PIT.What function I could modify and how can I write function
> to realize this idea?
> BTW,I wonder if a node will cache every contentobject when it comes
> in?What class and member function a node implement to cache a
> contentobject?
>
>
> Best regards.
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> ------------------------------
>
> Message: 4
> Date: Wed, 29 May 2013 12:06:48 +0800
> From: Saeid Montazeri <saeid.montazeri at gmail.com>
> To: ndnsim at lists.cs.ucla.edu
> Subject: [ndnSIM] Realistic but small topology for cache performance
> evaluation
> Message-ID:
> <CAM9UYj6pqc_74ese-v=Z5HjPENzaB2664q4PS_-nx-KyRuFc8w at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Dears in ndnSIM,
>
> I want to evaluate the cache performance in NDN. I need a realistic
> topology. I have seen some topology generators such as inet. In addition,
> I
> investigated some traces such as those measured by rocketfuel. However,
> the
> problem with these tools and traces is the topology scale. That is, the
> topology has a large number of nodes which make the execution time of the
> simulation very long. In addition, I need a topology which has at least
> two
> connected ISPs because I want to measure the exchanged traffic between
> ISPs.
>
> Please let me know if you have any suggestion.
>
> Best Regards,
> Saeid
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> ------------------------------
>
Hello,
I just wonna stick to the last sentence of the below message regards to
where should a new caching policy be implemented. I searched through some
related classes and figured out an option of how to do so and just want to
verify here or to let me know if someone has a better idea. I figured that
when using the stackHelper to create your nodes the constructor
automatically initiates the content store to use LRU policy and caching
every object along the way. The main reason for it is the implementation
class used, named as ndn-content-store-impl. That class inherits the main
functions from the ndn-content-store class which has just virtual
functions in it for the main operations that a content store has, e.g.
lookup, add of an object, print -as far as i remember. So, would it be ok
to implement a class that inherits the ndn-content-store class but
identify the add function differently - doing caching only under some
certain circumstances. If anyone has an opinion on this please let me
know.
Thanks in advance for your time!
Kind regards,
Andriana.
> Message: 5
> Date: Tue, 28 May 2013 23:21:53 -0700
> From: Alex Afanasyev <alexander.afanasyev at ucla.edu>
> To: ??? <blindeafer at 163.com>
> Cc: ndnsim at lists.cs.ucla.edu
> Subject: Re: [ndnSIM] How to get instant link load
> Message-ID: <513C38AB-85DB-4DB7-8F7B-A7234B1842FE at ucla.edu>
> Content-Type: text/plain; charset="utf-8"
>
> Hi!
>
> Can you define "instant" load more specifically? You can't have "instant"
> load, since it would be either 100% (packet "on the line") or 0% (nothing
> is on the line).
>
> In any case, to implement this, you could extend forwarding strategy to
> keep track of amount of sent/received data on each face. Here is some
> example (though not exactly what you're looking for)
> https://github.com/cawka/ndnSIM-ddos-interest-flooding/blob/master/extensions/stats.h
> how it can be implemented. In the example, the forwarding strategy
> extension keeps track of number of forwarded interests and number of
> unsatisfied. You can overload different methods (InInterest, InData,
> DidSendOutInterest, DidSendOutData) and get amount of sent/received data
> instead.
>
> After you have this module implemented, you can create a policy to control
> how DATA packets are cached. Currently, there are a number of policies
> available, including LRU, LFU, Random, Persistent, and some other. It is
> not the case with all policies that all passing by DATA packets will be
> cached. For example, with Random policy, there is always a chance that
> new item will be rejected. In your case, you would need to write a
> policy, that on every insert consults "stats" module and applies
> probabilistic decision whether to cache item or not.
>
>
> Here is just a little bit background that could be useful to understand
> content store (I made this example before for FIB, but it is good for
> Content Store as well):
>
> -----------------
>
> Content Store (as well as FIB and PIT) is organized using the underlying
> data structure that is a complex tree. Each node of the tree corresponds
> to a name component, and connection to child nodes is implemented as a
> hash array. If you want, you can check more details by looking into the
> source code in
> https://github.com/NDN-Routing/ndnSIM/blob/master/utils/trie/trie.h.
>
> An example
>
> Let say, Content Store has cached DATA packets with the following names:
>
> /a
> /a/b
> /a/d
> /b/a
> /b/b
>
> The structure that will be created would look like
>
> (root) --- a (*) ----- b (*)
> \ \
> \ \------ d (*)
> \
> \----- b ----- a (*)
> \
> \---- b (*)
>
> The nodes with (*) mean that at this level there is a payload (valid CS
> entry), which can be returned during the lookup process.
>
> Children on each level are stored in a hash-based container.
>
> In addition to this trie structure, each inserted item is also subject to
> a policy: every time an item is inserted, looked up, modified, or
> deleted, a policy is getting notified and can do some action, e.g., remove
> item, promote item, or do something else. Here are links to existing
> policy implementations:
> LRU:
> https://github.com/NDN-Routing/ndnSIM/blob/master/utils/trie/lru-policy.h
> LFU:
> https://github.com/NDN-Routing/ndnSIM/blob/master/utils/trie/lfu-policy.h
> Random:
> https://github.com/NDN-Routing/ndnSIM/blob/master/utils/trie/random-policy.h
> Persistent:
> https://github.com/NDN-Routing/ndnSIM/blob/master/utils/trie/persistent-policy.h
>
> -----------------
>
> ---
> Alex
>
> On May 28, 2013, at 6:49 PM, ??? <blindeafer at 163.com> wrote:
>
>> Hi all,
>> I have an idea about cache scheme.In this scheme,I want to get the
>> instant incoming link load everytime a contentobject come into a node
>> and the outgoing link load(s) according to PIT entry if the
>> contentobject is matched in PIT.What function I could modify and how can
>> I write function to realize this idea?
>> BTW,I wonder if a node will cache every contentobject when it comes
>> in?What class and member function a node implement to cache a
>> contentobject?
>>
>> Best regards.
>>
>>
>> _______________________________________________
>> ndnSIM mailing list
>> ndnSIM at lists.cs.ucla.edu
>> http://www.lists.cs.ucla.edu/mailman/listinfo/ndnsim
>
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