[ndnSIM] ConsumerWindow Timeouts

fabrizio saponaro fab.batta at gmail.com
Mon Feb 3 12:53:55 PST 2014

Hi Alex,
I working with this simple topology:

producer <---> r3 <--> r2 <--->r1<--->consumer

where consumer is a node with the ConsumerWindow application installed.
Capacities of the links, are 1Mbps for the r1-consumer 's link and 10Mbps
for the rest.
Each node has a serialized size pit large 10KB and the forwarding strategy
is BestRoute.

The consumer wants to download 1MB and starts with a window to 1, as
initial number of interests that will be send out without wainting for the

In the OnData() function of the ConsumerWindow class, I calculate the
number of retransmissions happened when seqNum>=m_seqMax and so when the
download is finished. The number of retransmission is the difference
between the interests sent and the data received. I increment the interest
counter in the funcion WillSendOutInterest() and the data counter in the
function OnData(). Then, I have another counter for when a timeout occurs.

Running the simulation, I can see, in the different routers, that the
maximum of pit size is never reached and the pit is filled only for a few
bytes. So, this might suggest that in the network, none interest has been
lost for "pit's size reason", but consumer receive an amount of datas lower
than the amount of interests (about 40% of difference). This large
difference is due to the trigger of several timeout that cause the

My question is, in this simple scenario, how is it possible that the r1
router not receive the interest sent by the consumer? And there are other
reasons that cause the timeouts' trigger?
In my opinion it's possible that the window's size increase too fast,
saturating the link. What do you think? If you agree, is there a way to set
a maximum size that the window can reach?

I hope you can help me.

Best regards,

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