[ndnSIM] Problems about the suppress of PIT

Alex Afanasyev alexander.afanasyev at ucla.edu
Mon Apr 28 15:47:36 PDT 2014

Hi Zhang,

It is a little bit confusing to me.  It doesn't make sense (and kind of impossible in ndnSIM) to create a new PIT entry for the same name prefix.  When you receive a similar Interest, you should just remember the incoming face inside the same PIT entry, but not to create a new one.

The question of whether to suppress the transmission of the interest further is a different one.  For that, you could modify ShouldSuppressIncomingInterest to always return false, removing function of "supporessing" similar Interest transmission.


On Apr 27, 2014, at 7:59 PM, zhangxuebei <zhangxuebei1215 at 163.com> wrote:

>  Hi!
> I use the ndnSIM to do my research about the influence of the suppress of PIT.
> So I want to turn down the function of suppress,that is when a CCN node receive a similar interest from different face,I need the PIT creates a new pit entry.(Do you understand me?)
> Now I think maybe I need to modify the function   OnInterest()  in ForwardingStrategy.cc . Is that right? but it is always fail, I really need your help!!!!
> Because my time is limited, I beg your reply sincerely!!
> Thank you sooooooo much!
> Best regards!
> Zhang
> p.s : This is the code I modified,but it is failed. Other place is the same as the original,just this section of OnInterest() is modified.
>  void
> ForwardingStrategy::OnInterest (Ptr<Face> inFace,
>                                 Ptr<Interest> interest)
> {
>    if (similarInterest && ShouldSuppressIncomingInterest (inFace, interest, pitEntry))
>      {
>        Ptr<pit::Entry> similarpitEntry = m_pit->Create (interest);
>        if (similarpitEntry != 0)
>          {
>            DidCreatePitEntry (inFace, interest, similarpitEntry);
>            similarpitEntry->AddIncoming(inFace);
>            similarpitEntry->UpdateLifetime(interest->GetInterestLifetime());
>            DidForwardSimilarInterest(inFace, interest,similarpitEntry );
>          }
>        else
>          {
>            FailedToCreatePitEntry (inFace, interest);
>            return;
>          }
>        //pitEntry->AddIncoming (inFace/*, interest->GetInterestLifetime ()*/);
>        // update PIT entry lifetime
>        //pitEntry->UpdateLifetime (interest->GetInterestLifetime ());
>        // Suppress this interest if we're still expecting data from some other face
>        //NS_LOG_DEBUG ("Suppress interests");
>        //m_dropInterests (interest, inFace);
>        //DidSuppressSimilarInterest (inFace, interest, pitEntry);
>        return;
>      }
>  }

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