[Ndn-interest] Delay forwarding in fw strategy

Adhy Satya adhysatya820 at gmail.com
Mon Jul 17 06:59:19 PDT 2017


Hi Klaus,

I'm working on a wireless scenario (my apologies! I forgot to clarify this
in my first email).
- Point 1 (Send the Data to a different interface): nodes will broadcast
packets on the same interface (WiFi);
- Point 2 (Delay the Data packet): since wireless is broadcast in nature,
all nodes in the communication range will listen to Interest/Data
transmissions and will rebroadcast roughly at the same time. Delayed
retransmissions help to avoid collisions in the wireless channel. This
technique was used in the NDN Car2Car
<https://github.com/cawka/ndnSIM-nom-rapid-car2car/blob/master/extensions/ndn-fw-v2v.cc>
work (ndnSIM) and other works, but I think they all used simulators. In the
Car2Car, the delay was performed in a customized face, not in the strategy.





On Fri, Jul 14, 2017 at 11:19 AM, Klaus Schneider <klaus at cs.arizona.edu>
wrote:

>
>
> On 07/13/2017 08:47 PM, Adhy Satya wrote:
>
>> Hi Junxiao,
>>
>> Thank you for your answer. I missed that detail on the NFD developer
>> guide (that the strategy controls only Interests packets).
>> In my case, each data packet is associated with a unique Interest;
>> therefore, by adopting an Interest digest the strategy should be able to
>> control Data packets.
>>
>
> You can use the function beforeSatisfyInterest() that is called whenever a
> Data packet arrives. Thus you can perform certain actions (like storing RTT
> measurements) on each Data packet. You just cannot:
>
> 1. Send the Data to a different interface. Or
>
> 2. Delay the Data packet.
>
> Was this feature ever implemented? (it shows as 0% done in issue 3333 <
>> https://redmine.named-data.net/issues/3333>). Are there any sample
>> implementations?
>>
>
> One could design the strategy so that beforeSatisfyInterest() is a
> mandatory step in the pipeline between "incoming Data" and "outgoing Data".
> This would extend the functionality and probably support what you want.
>
> However, the strategy was not designed that way (presumably) because
> nobody saw a use case.
>
> For (1): why would anyone want to send the Data to a different face? It
> would be dropped there as "unsolicited".
>
> For (2): why do you want to delay the Data inside the strategy? Maybe
> there's an easier solution for you like
>
> - delaying Data/Interests at consumer or producer. Or
> - delaying the Interests inside the strategy.
>
>
> Best regards,
> Klaus
>
>
>
>
>
>>
>> Thanks
>>
>>
>>
>>
>>
>> On Thu, Jul 13, 2017 at 4:45 PM, Junxiao Shi <
>> shijunxiao at email.arizona.edu <mailto:shijunxiao at email.arizona.edu>>
>> wrote:
>>
>>     Hi Adhy
>>
>>     The method to delay Interest forwarding is explained in this answer:
>>     http://www.lists.cs.ucla.edu/pipermail/ndnsim/2017-July/003952.html
>>     <http://www.lists.cs.ucla.edu/pipermail/ndnsim/2017-July/003952.html>
>>     Forwarding strategy does not have control over Data forwarding nor
>>     can it delay Data forwarding. The reason is explained in this
>>     answer:
>>     http://www.lists.cs.ucla.edu/pipermail/ndnsim/2017-July/003961.html
>>     <http://www.lists.cs.ucla.edu/pipermail/ndnsim/2017-July/003961.html>
>>     Also, you need to ensure your Interest name (including any “extra
>>     name components”) is a prefix of the Data name. Otherwise, Data does
>>     not satisfy Interest and will not be received by the consumer.
>>
>>     Yours, Junxiao
>>
>>     On Jul 13, 2017, at 11:43 AM, Adhy Satya <adhysatya820 at gmail.com
>>>     <mailto:adhysatya820 at gmail.com>> wrote:
>>>
>>>     Hi,
>>>
>>>     My consumer and producer applications send Interest and Data
>>>     packets with extra name components. I wrote a custom forwarding
>>>     strategy that reads this name components and forward packets with
>>>     certain delay.
>>>
>>>     I'm using NFD 0.5.0 and ndn-cxx 0.5.0. I'm unsure where to
>>>     implement the timer. It seems that if I implement a timer to call
>>>     "this->sendInterest()" it will block the forwarder for a certain
>>>     amount of time.
>>>
>>>     Can you assist me on this issue please?
>>>
>>>     Thank you
>>>     _______________________________________________
>>>     Ndn-interest mailing list
>>>     Ndn-interest at lists.cs.ucla.edu <mailto:Ndn-interest at lists.cs.
>>> ucla.edu>
>>>     http://www.lists.cs.ucla.edu/mailman/listinfo/ndn-interest
>>>     <http://www.lists.cs.ucla.edu/mailman/listinfo/ndn-interest>
>>>
>>
>>
>>
>>
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