[ndnSIM] Inconsistent number of sent packets

Alex Afanasyev alexander.afanasyev at ucla.edu
Wed Apr 17 11:23:08 PDT 2013


Can you send out scenario (or link to scenario), so I can try to debug the problem on my machine?

routingCost is basically an aggregated cost for the specific path.  If you're using globalRoutingController, it sums up all the specified metrics on the path.  For example, if you have this topology

node1 ------ node2 ------- node3 ------- node4

and all metrics for each link is 10, then routing cost on node1 to forward towards node4 using the only available face would be 30.

If you are using "EnableDefaultRoute" in ndn::StackHelper, then this value doesn't really mean anything and suggests only that this "default" is the least preferred option to forward interests.

---
Alex

On Apr 17, 2013, at 8:36 AM, yao hu <huyao0107 at gmail.com> wrote:

> Hi Alex,
> 
> I did not specify any randomization using Randomize parameter. I am not sure whether all the interests are consumed at the first attempt, but if that is a reason, the retransmitted Interest packets are not counted into "Tx Packets"? Besides, I am not sure about the meaning of routingCost column (2147483647) in FIB. Does it has something different from the 'metric' which affects the forwarding strategy to select the BestRoute? Could I specify it somewhere?
> 
> Sorry for many questions. Thanks very much!
> 
> Regards,
> huyao
>  
> 
> 
> 2013/4/17 Alex Afanasyev <alexander.afanasyev at ucla.edu>
> Hi huyao,
> 
> Did you specify any randomization for inter-interest gap using Randomize parameter (uniform, exponential)?  Though, by default there is no randomization.
> 
> Btw. Do all your interest are getting satisfied from the first attempt?  If not, the difference can come from the interest retransmission, since those that needs to be retransmitted are sharing the same "cbr" constraints as new interests.
> 
> ---
> Alex
> 
> On Apr 16, 2013, at 8:32 AM, yao hu <huyao0107 at gmail.com> wrote:
> 
> > Hi Alex,
> >
> > Just now, in order to verify my modification I used CustomerCbr to produce a certain number of Interest from a specific consumer, however, I found that there is a little difference between expectation and simulation result. For example, I set the Interest frequency as 10 (packets per second) for 20 seconds, the result is the number of sent packets is 200 which is the same as theoretic value. But if I set the Interest frequency as 100 for 20 seconds, the simulation result is the number of sent packets is 1805 which is less than the theoretic value 2000. What is the possible reason for this phenomenon? (No packets are sent from other faces)
> >
> > Thanks for your reply!
> >
> > Regards,
> > huyao
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> 
> 
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