[Ndn-interest] Problem of PIT not aggregating Interests

[Junxiao Shi]

Hi yjinking

I don't see any problems in the pcap files. Aggregation worked perfectly:
only one Interest ever went to the producer.
Is this from unmodified NFD? If you are trying to report a bug, please
revert all local changes before capturing traffic.
Also, your NFD version appears to be outdated. Please upgrade.

Yours, Junxiao

On Wed, Apr 24, 2019 at 7:17 AM yjinking at mail.ustc.edu.cn <
yjinking at mail.ustc.edu.cn> wrote:

> Hi, Junxiao,
> Thanks for your reply. Here are some information you mentioned.
> Today, We added some codes in forwarder.cpp to print some information when
> Interests passing and reconfigure the Producer's execution time. We found,  two
> Interest packets with same name from one node will have the same Nonce,
> then forwarder will forward just one Interest.
> And two Interest packets with same name from two different nodes will
> have different Nonce. Then forwarder will forward both them and Producer responded twice.
> Unlikely the previous time, two consumers received the same Data, which is
> exactly what procurer first replied.
>
> "Aggregation vs retransmission depends on exact timing". Does that mean
> the possibility of aggregation is quite low?
>
> ------------------------------
>
>
> *From:* Junxiao Shi <shijunxiao at email.arizona.edu>
> *Date:* 2019-04-23 10:52
> *To:* yjinking <yjinking at mail.ustc.edu.cn>
> *CC:* ndn-interest <ndn-interest at lists.cs.ucla.edu>
> *Subject:* Re: [Ndn-interest] Problem of PIT not aggregating Interests
> Hi yjinking
>
> Aggregation vs retransmission depends on exact timing.
> Can you capture traffic on the forwarder node as a pcap file with tcpdump?
> I can have a look.
> Also paste the output of 'nfdc status' and 'nfdc face' and 'nfdc strategy'
> commands.
>
> Yours, Junxiao
>
> On Mon, Apr 22, 2019, 22:16 yjinking at mail.ustc.edu.cn <
> yjinking at mail.ustc.edu.cn> wrote:
>
>>
>> Hi,all:
>> We encountered a problem that PIT can not aggregate two Interest packets
>> with same name from two different nodes, but it can aggregate two Interest
>> packets with same name from one nodes.
>> We run NFD on 4 physical nodes consisting "Y"-shape topology(central node
>> is forwarder, one Producer, two Consumers). Then two experiment were
>> conducted:
>>
>> 1. We run ./examples/producer on producer node. We extended Producer's
>> execution time to 5 seconds when Producer receives Interest. Then two
>> Interest packets with same name from two different nodes were issued nearly
>> at the same time. After about 5 second and 10 second, two Consumers
>> received their Data packets subsequently. And two Data packets' timestamp
>> were different. Producer responded twice.
>>
>> 2. In another experiment, all is same with the first experiment, except
>> that we only use one consumer node. Two Interest packets with same name
>> from one nodes were issued nearly at the same time. After about 5 seconds,
>> the consumer node received 2 Data packets with same timestamp subsequently.
>> Producer responded once.
>>
>> According to the process of NDN, the result of the first experiment is
>> very strange. Why didn't PIT aggregate the second Interest? Does NFD build
>> PIT for each face separately? or maybe is there anything wrong in our
>> experiment?
>>
>> Plus, how can I print the content of FIB/CS/PIT on real time? Does NFD
>> provide any interfaces?
>>
>>
>> Thank you!
>> ------------------------------
>>
>>
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