[ndnSIM] Can I create multiple PIT entries for one Interest?

[Lixia Zhang]

On Dec 12, 2019, at 10:38 PM, 大熊 浩也 <okuma at stu.kobe-u.ac.jp> wrote:
> 
> Dear Lixia Zhang, Spyridon Mastorakis
> 
> Thank you for your reply.
> Also sorry for my late reply.
> 
> I am researching how to apply NDN to encoded communication using cache files.
> 
> Specifically, the user requests the desired file and an encoded file that can decode the desired file using its own cache at the same time, and increases the candidates for the requested file.
> The above method aims to reduce the number of Interest hops.
> 
> For example, when a user who desires the file “A” caches the file “B”, the user requests the file “A+B” together with the file “A”. Even if the user receives the file "A+B", the desired file "A" can be obtained by XORing the received file "A+B" and the user's cache file "B".

> 
> What I am trying to implement in the ndnSIM Forwarder class is a node that has received an Interest that contains a single name "/prefix/A/%FE%00/prefix/A+B/%FE%00" configure a PIT entry for each requested file. (In the above example, I would like to create PIT entries in two Interests: "/prefix/A/%FE%00" and "/prefix/A+B/%FE%00")


In the above you developed an interesting scenario.
Here is my view: we need to clarify the assumption here.
Although NDN uses app names to fetch data, one needs to keep in mind that routers/forwarders do not understand the name semantics, they forward interests and data packets by matching the binary strings of the names.

for example the prefixes /prefix/A, /prefix/B, and /prefix/A+B are independent ones; a router would not know their relations.
So a router wont be able to perform any function based on its semantic understanding of the name "/prefix/A/%FE%00/prefix/A+B/%FE%00"

I believe you need to write your own application to do that

> In ndnSIM, in the onIncomingInterest method of Forwarder.cpp, I got the requested file name, and then modified it to repeat the process of configuring the PIT entry by setting the file name to Interest for the number of requested files. I wanted to try.
> However, in the onIncomingInterest method, the variable indicating interest is const, so I am worried that I cannot set the divided file name.

routers cannot modify received interest names

> I am looking forward to your guidance and support.
> 
> Best Wishes,
> 
> Hiroya Okuma
> 
> 
> On 2019/12/11 5:56, Lixia Zhang wrote:
>> Dear Hiroya Okuma,
>> could you please explain what is the research question that you are looking into?
>> If we know the problem you try to solve, then we can work out a good solution.
>> Using a single interest to fetch multiple packets can potentially lead to a number of negative impacts (that I am not sure whether you are aware of)
>> Lixia
>>> On Dec 10, 2019, at 5:36 AM, 大熊 浩也 <okuma at stu.kobe-u.ac.jp> wrote:
>>> 
>>> Hello Everyone,
>>> 
>>> I am thinking of fulfilling multiple file requests with one Interest transmission.
>>> (I know that it is different from the original idea of NDN.)
>>> 
>>> For example, a node that receives an Interest that stores a name such as "/prefix/file_A/%FE%01/prefix/file_B/%FE%01" needs to create two PIT entries, but I don't know how to fix the forwarder class.
>>> In particular, the setName function of the Interest class cannot be used because the interest variable of the onIncomingInterest function is const.
>>> 
>>> I am looking forward to your guidance and support.
>>> 
>>> Best Wishes,
>>> 
>>> Hiroya Okuma
>>> 
>>> 
>>> _______________________________________________
>>> ndnSIM mailing list
>>> ndnSIM at lists.cs.ucla.edu
>>> http://www.lists.cs.ucla.edu/mailman/listinfo/ndnsim
> 
> -- 
> ********************************************
> 大熊 浩也　(Hiroya Okuma)
> 神戸大学 工学研究科 電気電子工学専攻
> 情報通信研究室所属
> E-mail: okuma at stu.kobe-u.ac.jp
> ********************************************
> 
>