[ndnSIM] Using the setExpiryTImer

Sun Nov 25 01:44:22 PST 2018

I have made the necessary changes. I have a small problem now. I have a
separate working repository where I have the custom apps,custom strategies
and and my scenarios. When I make the changes in the Strategy.cpp, it
doesn't seem to reflect in my simulations(however, it does in reflect in
the scenarios of  examples folder inside the ndnSIM ). I am not sure how to
build those files(the files within NFD, ndn.cxx etc )  for them to work
with my separate repository.

On Sun, Nov 25, 2018 at 6:42 PM Ashish Pradhan <ashishpradhan1162 at gmail.com>
wrote:

> I have made the necessary changes. I have a small problem now. I have a
> separate working repository where I have the custom apps,custom strategies
> and and my scenarios. When I make the changes in the Strategy.cpp, it
> doesn't seem to reflect in my simulations. I am not sure how to build those
> files(the files within NFD, ndn.cxx etc )  for them to work with
>
>
>
> On Sun, Nov 25, 2018 at 2:06 PM Teng Liang <philoliang at email.arizona.edu>
> wrote:
>
>> Hi Ashish,
>>
>> To keep it simple, one PIT entry represents a pending Interest, which
>> guides Data forwarding. One router may receive Interests with the same name
>> from multiple different downstreams. On receiving the Data that can satisfy
>> these Interests, the router is able to multicast the Data to all the
>> downstreams sending the Interests. PIT entry's in-record represents the
>> face to downstream, and each in-record has an expiry timer (=Interest
>> lifetime). PIT entry itself has a different expiry timer that is refreshed
>> by the latest PIT in-record expiry timer (code:
>> https://github.com/named-data/NFD/blob/master/daemon/fw/forwarder.cpp#L181-L184
>> )
>> Chapter 3.4 in NFD developer guide explains more details about PIT (
>> https://named-data.net/wp-content/uploads/2016/10/ndn-0021-7-nfd-developer-guide.pdf).
>>
>>
>> For you scenario, one hack that may work is to remove the expiry timer
>> check on pit in-record check (
>> https://github.com/named-data/NFD/blob/master/daemon/fw/strategy.cpp#L216)
>> instead of step 2 in my previous email.
>>
>> Teng
>> On 11/24/18 8:36 PM, Ashish Pradhan wrote:
>>
>> Hi Teng,
>>
>> Thank you so much for understanding my problem. I will try to implement
>> it as you said. In the mean time can you please explain the difference
>> between "setting expiry timer of the pit entry" and  "setting expiry timer
>> of the pit entry's in record"
>>
>> Best Regards,
>> Ashish Pradhan
>>
>>
>>
>> On Sun, Nov 25, 2018 at 12:08 PM Teng Liang <philoliang at email.arizona.edu>
>> wrote:
>>
>>> Hi Ashish,
>>>
>>> I agree with you that simply extending PIT entry lifetime (using
>>> setExpiryTimer) will not work for "One-Interest-Many-Data" in NFD, because
>>> when you invoke Strategy::sendDataToAll for the second (or latter) Data,
>>> the PIT entry's in-record is already deleted. You could try these changes:
>>>
>>>    1. Avoid deleting PIT entry's in-record after forwarding data by
>>>    - commenting out this line:
>>>       https://github.com/named-data/NFD/blob/master/daemon/fw/strategy.cpp#L203
>>>    2. Extending PIT entry's in-record lifetime by
>>>       - adding an update function with the parameter time duration in
>>>       pit::FaceRecord (the base class of pit::InRecord)
>>>       - setting pit entry's in-record lifetime when setting pit entry's
>>>       lifetime (invoking the previous added function within
>>>       Forwarder::setExpiryTimer:
>>>       https://github.com/named-data/NFD/blob/master/daemon/fw/forwarder.cpp#L516
>>>       )
>>>    3. Deleting PIT entry's in-records in Forwarder::onInterestFinalize
>>>    (this could be optional)
>>>
>>> Thanks,
>>> Teng
>>>
>>>
>>> On 11/24/18 5:08 PM, Ashish Pradhan wrote:
>>>
>>> Hi Xinyu,
>>>
>>> Thank you for your reply.
>>>
>>> I am fully aware of the One-Interest-One-Data behavior. However, I have
>>> a custom app(a producer) where it produces multiple data for a single
>>> interest. Then I want all the produced data to reach the consumer. So for
>>> that, I am implementing a custom strategy where the PIT entry lifetime of
>>> the nodes are extended after it receives the first data from the producer.
>>> I have followed the ndnSIM API documentation for it.
>>>
>>> beforeSatisfyInterest documentation:
>>>
>>> http://ndnsim.net/current/doxygen/classnfd_1_1fw_1_1Strategy.html#a97b4f1e5496c4dd08cc17b5d3d265f08
>>>
>>> setExpiryTimer documentation:
>>>
>>> http://ndnsim.net/current/doxygen/classnfd_1_1fw_1_1Strategy.html#a967ad88184231f79b245ce202e9d4ea7
>>>
>>> Best regards,
>>> Ashish Pradhan
>>>
>>>
>>>
>>> On Sun, Nov 25, 2018 at 2:21 AM Xinyu Ma <bitmxy at gmail.com> wrote:
>>>
>>>> Hello, Pradhan
>>>>
>>>> I’m sorry I don’t understand why you want to extend the PIT entry’s
>>>> lifetime and what you mean by “data response other than the first one”.
>>>> NDN follows One-Interest-One-Data, so the PIT entry should be deleted
>>>> after receiving the data.
>>>> You can send another Interest if you still want the PIT entry to be
>>>> there.
>>>>
>>>> Best,
>>>> Xinyu Ma.
>>>>
>>>> On Nov 24, 2018, at 6:20 AM, Ashish Pradhan <
>>>> ashishpradhan1162 at gmail.com> wrote:
>>>>
>>>> Hi all,
>>>>
>>>> I am trying to use the setExpiryTimer to extend the PIT entry's
>>>> lifetime. However the data response other than the first one is not being
>>>> forwarded back to the consumer. I have included the setExpiryTimer in the
>>>> beforeSatisfyInterest function as follows:
>>>> "NFD_LOG_DEBUG("beforeSatisfyInterest pitEntry=" << pitEntry->getName()
>>>> <<
>>>>                 " inFace=" << inFace.getId() << " data=" <<
>>>> data.getName());
>>>>
>>>>   this->Strategy::setExpiryTimer(pitEntry,
>>>> ndn::time::milliseconds(100));"
>>>>
>>>> Is there any thing that needs to be added?
>>>>
>>>> After looking at the sendData function there is this line
>>>> "pitEntry->deleteInRecord(outFace);". If it is deleting the inRecord how
>>>> does the setExpiryTimer help to preserve the entry?
>>>>
>>>> Best regards,
>>>> Ashish Pradhan
>>>>
>>>> _______________________________________________
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>>>> ndnSIM at lists.cs.ucla.edu
>>>> http://www.lists.cs.ucla.edu/mailman/listinfo/ndnsim
>>>>
>>>>
>>>>
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