[Ndn-interest] Loop Detection Issue

[marxer at claudio.li]

On 08/03/16 14:28, Lan Wang (lanwang) wrote:
> They have different nonces but if the PIT entry created by C1 has not 
> been removed, then C2 may be suppressed.   This is the dangling PIT 
> entries problem.The solutions (already implemented in NFD) are the 
> following:

Yes, this is what we meant in the example.

> 
> 1. some strategies, e.g., recent versions of BestRoute) allow interest 
> retransmission: when an interest is forwarded, a suppression timer is 
> set on the PIT.  When the timer expires, it  may forward any new 
> Interest matching the PIT (and then set the suppression timer again).
> 
> 2. when X detects an Interest with a duplicate nonce, it sends a 
> duplicate NACK  which may be further forwarded to clear the dangling 
> PIT entries at the nodes that sent the interest.  When the PIT entry is 
> cleared, new interest with the same name can be forwarded.  Right now 
> some strategies (not all) in NFD handle the NACKs correctly.

Yes, this works. A question regarding the implementation: According to 
the NFD developer guide, the PIT does not hold nonce values. Thus Z can 
not fully reconstruct the interest from C2. Does Z generate a new nonce? 
If yes: Not sure but intuitively I think that loop partially detection 
might be broken if the green interest was also part of a loop (because Z 
changes its nonce).

> 
> Lan

Thanks to all of you for the explanations,
Claudio

> 
>> On Aug 3, 2016, at 4:54 AM, Lixia Zhang <lixia at cs.ucla.edu> wrote:
>> 
>> I have a few other questions to the specifics of the scenario.
>> for a short answer quick: interests form C1 and C2 carry different 
>> nonces, so your concern on the last slide should not happen as I see.
>> 
>>> On Aug 3, 2016, at 1:15 AM, marxer at claudio.li wrote:
>>> 
>>> Hi all,
>>> 
>>> Urs and I constructed a situation in which we think the network does 
>>> not behave as expected (attached PDF). Can this happen in the wild or 
>>> did we oversee something?
>>> 
>>> Thanks,
>>> Urs and Claudio
>>> 
>>> <interest-looping.pdf>_______________________________________________
>>> Ndn-interest mailing list
>>> Ndn-interest at lists.cs.ucla.edu
>>> http://www.lists.cs.ucla.edu/mailman/listinfo/ndn-interest
>> 
>> 
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