[ndnSIM] can't get Nack when congestion

[Xiaoke Jiang]

Maybe in OnContentObject, the packet should be checked first, if it is a Nack, call onNack to process it.


thanks

My Regards,
Xiaoke Jiang （蒋小可）

Ph.D Candidate,
Dept. of Computer Science and Technology,
Tsinghua University, P. R. China

On Mar 8, 2013, at 4:07 PM, Xiaoke Jiang <shock.jiang at gmail.com> wrote:

> Hi Alex,
> 
> 
> in Consumer.cc,  in the function OnContentObject, according to your email, it may also process Nack, right? if hopCount = -1, it means the Packet is a Nack, but it still print that the Data is comming.
> 
> 
>   uint32_t seq = boost::lexical_cast<uint32_t> (contentObject->GetName ().GetComponents ().back ());
>   NS_LOG_INFO ("< DATA for " << seq);
> 
>   int hopCount = -1;
>   FwHopCountTag hopCountTag;
>   if (payload->RemovePacketTag (hopCountTag))
>     {
>       hopCount = hopCountTag.Get ();
>     }
> 
> 
> That's quit strange.
> 
> thanks
> 
> My Regards,
> Xiaoke Jiang （蒋小可）
> 
> Ph.D Candidate,
> Dept. of Computer Science and Technology,
> Tsinghua University, P. R. China
> 
> On Mar 8, 2013, at 11:37 AM, Xiaoke Jiang <shock.jiang at gmail.com> wrote:
> 
>> Hi Alex,
>> 	I add an issue here: https://github.com/NDN-Routing/ndnSIM/issues/26 , but I am not sure it is what you want.
>> 
>> P.S, when do you plan to merge new Rtt Estimator?
>> 
>> 
>> thanks
>> 
>> My Regards,
>> Xiaoke Jiang （蒋小可）
>> 
>> Ph.D Candidate,
>> Dept. of Computer Science and Technology,
>> Tsinghua University, P. R. China
>> 
>> On Mar 8, 2013, at 11:31 AM, Alex Afanasyev <alexander.afanasyev at ucla.edu> wrote:
>> 
>>> Hi Xiaoke,
>>> 
>>> Yes. I haven't yet had chance to make the implementation and -1 will mean that somewhere on the way Interest got "NACKed".  Can you open an issue for this on github?  
>>> 
>>> Thanks,
>>> Alex
>>> 
>>> On Mar 7, 2013, at 7:16 PM, Xiaoke Jiang <shock.jiang at gmail.com> wrote:
>>> 
>>>> Hi Alex,
>>>> 	I am not sure whether you have improve hop count or not. Now as far as I can understand,  hop count = -1 means Interest got Nack (from provider or middle router). 
>>>> 	Is it accurate?
>>>> 
>>>> 
>>>> thanks
>>>> 
>>>> My Regards,
>>>> Xiaoke Jiang （蒋小可）
>>>> 
>>>> Ph.D Candidate,
>>>> Dept. of Computer Science and Technology,
>>>> Tsinghua University, P. R. China
>>>> 
>>>> On Jan 23, 2013, at 1:36 AM, Alex Afanasyev <alexander.afanasyev at ucla.edu> wrote:
>>>> 
>>>>> 
>>>>> On Jan 21, 2013, at 11:18 PM, Xiaoke Jiang <shock.jiang at gmail.com> wrote:
>>>>> 
>>>>>> Thank you Alex. Your email really makes sense.
>>>>>> 
>>>>>> I think for a Interest-Nack there is same problem with Interest-Content, hop count for last transmission and hop count for whole transmission(This is quit important, which can measure hop cost of request), what do you think?
>>>>>> 
>>>>>> For our trace, there is trace information for those interest who gets its data, in this case, if hopcount=-1, it means a Nack return but not data, is it suitable to not print trace information, RIGHT?
>>>>>> 
>>>>>> FYI,  it's quit strange, because this code is inside OnContent function, but not OnNack.
>>>>> 
>>>>> There is another thing with hop counting.  It is implemented using packet tags, which means that packets tags in the Interest should be transferred to the Content Object.  With NACKs, these tags are getting lost when NACK is generated, because I didn't consider tags when I originally implemented them.  As a result, as soon as something get nacked, the tag is lost and can't reappear again in ContentObject.
>>>>> 
>>>>> The "fix" to preserve hop count in NACKs is trivial.  Less trivial is to count whole transmission and last transmission separately...
>>>>> 
>>>>> --
>>>>> Alex
>>> 
>> 
> 

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