[ndnSIM] Drop cached data in ndnsim

[Spyridon Mastorakis]

Yes, the freshness period is set by the data producer.

If you really want to erase an entry from CS, the erase method of CS should work.

Spyridon (Spyros) Mastorakis
Assistant Professor
Computer Science Department
University of Nebraska, Omaha
Peter Kiewit Institute Room 175A
https://sites.google.com/site/spyridonmastorakis

On Feb 13, 2020, at 2:17 AM, Zeinab Rezaiefar <zeinab.rezaiefar at gmail.com<mailto:zeinab.rezaiefar at gmail.com>> wrote:

Dear Spyridon,
I have noticed that data accessed from cs::Entry is constant so I cannot change the freshness period of data and set it to zero. Therefore, I will receive an error with following commands in the forward.cpp file:
for(ns3::Ptr<ns3::ndn::cs::Entry> csentry= m_csFromNdnSim->Begin(); csentry!= m_csFromNdnSim->End(); csentry=m_csFromNdnSim->Next(csentry))
{
csentry->GetData()->setFreshnessPeriod(time::milliseconds(0));
}

error :
../src/ndnSIM/NFD/daemon/fw/forwarder.cpp:221:61: error: passing ‘std::__shared_ptr_access<const ndn::Data, (__gnu_cxx::_Lock_policy)2, false, false>::element_type’ {aka ‘const ndn::Data’} as ‘this’ argument discards qualifiers [-fpermissive]
 csentry->GetData()->setFreshnessPeriod(time::milliseconds(0));


However, maybe I understood something wrong from your solution.
I will be really grateful to know your opinion about this and your another solution regarding this issue.
Thanks
Bets regards
Zeinab

On Wed, Feb 12, 2020 at 5:48 PM Zeinab Rezaiefar <zeinab.rezaiefar at gmail.com<mailto:zeinab.rezaiefar at gmail.com>> wrote:
Dear Spyridon,
Thank you so much for your answer and help. It is a good trick to not reply Interest with the cached data. However, as I understand data will not be deleted from the cache so
in the case that I need to consider limited cache size, I may face a problem in evaluating the method. I prefer this data will be deleted from the cache so there will enough space for another data. If it does not mind, may I know your another solution as well.
Thank you so much for time and help
Best regards
Zeinab

On Tue, Feb 11, 2020 at 11:54 PM Spyridon Mastorakis <smastorakis at unomaha.edu<mailto:smastorakis at unomaha.edu>> wrote:
One thing you can do without actually dropping any cached packets (and it is a straightforward “hack”) is to set the freshness period of data packets to 0 (or something very close to that) and set the MustBeFresh flag of Interests to true (so that you simply ignore stale cached data packets):

https://named-data.net/wp-content/uploads/2018/08/hoticn18realtime-retrieval.pdf<https://urldefense.proofpoint.com/v2/url?u=https-3A__named-2Ddata.net_wp-2Dcontent_uploads_2018_08_hoticn18realtime-2Dretrieval.pdf&d=DwMFaQ&c=Cu5g146wZdoqVuKpTNsYHeFX_rg6kWhlkLF8Eft-wwo&r=eI5Bh74ovG-uIXQ5ksQETSPgRFzmJXjIZXneCqw580E&m=TlLWo0V2mY6hXNl5sm9tOM6OXdVtEhT0bVm3jDl6bfU&s=sRiAexvDBsuR4Q8QueXsUl2kdtfuFTpJ85-XMsh1Jrk&e=>

If you really need to drop the packets, then I can give you another solution.

Spyridon (Spyros) Mastorakis
Assistant Professor
Computer Science Department
University of Nebraska, Omaha
Peter Kiewit Institute Room 175A
https://sites.google.com/site/spyridonmastorakis<https://urldefense.proofpoint.com/v2/url?u=https-3A__sites.google.com_site_spyridonmastorakis&d=DwMFaQ&c=Cu5g146wZdoqVuKpTNsYHeFX_rg6kWhlkLF8Eft-wwo&r=eI5Bh74ovG-uIXQ5ksQETSPgRFzmJXjIZXneCqw580E&m=TlLWo0V2mY6hXNl5sm9tOM6OXdVtEhT0bVm3jDl6bfU&s=Oa5Nwbou7OqP9pty6UVe4Iy0afQ6mofOxuovgVyMohk&e=>



On Feb 11, 2020, at 1:49 AM, Zeinab Rezaiefar via ndnSIM <ndnsim at lists.cs.ucla.edu<mailto:ndnsim at lists.cs.ucla.edu>> wrote:

Hello there,
In continue of my previous email regarding dropping cached data, I have noticed that I need to erase data (using before evict signal)from cache and also clean up the index from policy. Since I want to command the cache to erase data from the forward.cpp file, I would like to know I can use Cs:: erase function to erase data from cache ?
May I know that I need still to cleanup index from policy as well.
I will be grateful to know our suggestions and guidance
Thanks
Best regards
Zeinab



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