[ndnSIM] Tracing RTT values of PIT entries

[Alex Afanasyev]

Hi Amin,

>From what I can guess, other PIT entries are simply getting satisfied. The three that you're seeing is basically a "pipeline" based on bandwidth-delay-product in the system.

---
Alex

On Nov 27, 2013, at 4:25 AM, Amin Karami <amin at ac.upc.edu> wrote:

> Hi Alex,
> I design a simple scenario as follows:
> c1--->
> c2---> R3 ----> R2 ----> p1
> c3--->
> 
> c1,c2 and c3 are connected to R3. In the first 3 seconds, just c1 sends Interest packets. When I printed the RTT values of PIT entries in R3, I face with below output:
> 
> 1    R3    PIT Size: 3
> =========
> /dst1/%00%01P
> mean of RTT: 0.00966371, Variance of RTT: 0.000361557
> Prefix: /dst1/%00%01P
> In: dev[10]=net(0,0-10)
> Out: dev[10]=net(1,9-10)
> Nonces: 2647520711
> =========
> /dst1/%00%01R
> mean of RTT: 0.00966371, Variance of RTT: 0.000361557
> Prefix: /dst1/%00%01R
> In: dev[10]=net(0,0-10)
> Out: dev[10]=net(1,9-10)
> Nonces: 3120749414
> =========
> /dst1/%00%01Q
> mean of RTT: 0.00966371, Variance of RTT: 0.000361557
> Prefix: /dst1/%00%01Q
> In: dev[10]=net(0,0-10)
> Out: dev[10]=net(1,9-10)
> Nonces: 315221540
> 
> 2    R3    PIT Size: 3
> =========
> /dst1/%00%02%C6
> mean of RTT: 0.0100666, Variance of RTT: 0.000979842
> Prefix: /dst1/%00%02%C6
> In: dev[10]=net(0,0-10)
> Out: dev[10]=net(1,9-10)
> Nonces: 2858765059
> =========
> /dst1/%00%02%C7
> mean of RTT: 0.0100666, Variance of RTT: 0.000979842
> Prefix: /dst1/%00%02%C7
> In: dev[10]=net(0,0-10)
> Out: dev[10]=net(1,9-10)
> Nonces: 629247679
> =========
> /dst1/%00%02%C8
> mean of RTT: 0.0100666, Variance of RTT: 0.000979842
> Prefix: /dst1/%00%02%C8
> In: dev[10]=net(0,0-10)
> Out: dev[10]=net(1,9-10)
> Nonces: 2514818005
> 
> 
> The rate of sending Interests is 400 per second for c1. As you seen, in each second, just 3 entries accommodate in PIT for routing purpose in FIB. What is the problem? Where is other about 397 Interest packets?
> 
> My implementation for printing RTT values are:
> 
> void PeriodicStatsPrinter (Ptr<Node> node, Time next)
> {
> Ptr<ndn::Pit> pit = node->GetObject<ndn::Pit> ();
>  std::cout << Simulator::Now ().ToDouble (Time::S) << "\t"
>            << Names::FindName (node) << "\t"
>            << "PIT Size: " << pit->GetSize () << "\t"
> for (Ptr<ndn::pit::Entry> entry = pit->Begin (); entry != pit->End (); entry = pit->Next (entry))
>  {
>    std::cout << "=========" << std::endl;
>    std::cout << entry->GetPrefix () << std::endl;
>    for (FaceMetricContainer::type::index<i_nth>::type::iterator metric = entry->GetFibEntry()->m_faces.get<i_nth> ().begin(); metric != entry->GetFibEntry()->m_faces.get<i_nth> ().end(); metric++)
>    {
>    std::cout << "mean of RTT: " << metric->GetSRtt ().ToDouble(Time::S) << ", Variance of RTT: " << metric->GetRttVar().ToDouble(Time::S) << "\n";
>    }
>     std::cout << *entry << std::endl;
>  }
>  Simulator::Schedule (next, PeriodicStatsPrinter, node, next);
> }
> 
> 
> 
> Best Regards,
> Amin
> 
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