[Ndn-interest] how to set freshnessSecond?

ndn ndn ndn at sqh.me
Wed Jul 29 19:48:18 PDT 2015


Dear Steve,

Thanks for you reply,I think I misunderstood "Must be fresh" literally.
In my point of view,"Must be fresh" means ndn Interests  must get the
newest data from publisher. Set a freshness period can help me to solve
it.At first,I didn't find any way to set freshness value,but now I find it
though you help.just using Data. getMetaInfo() and set it.
MemoryContentCache is a good way to acheive it,I will try it.


Thanks for your help and reply, forgive my poor english spell.
qhsong

2015-07-30 10:15 GMT+08:00 Steve DiBenedetto <dibenede at cs.colostate.edu>:

>
>
> On Wed, Jul 29, 2015 at 7:58 PM, ndn ndn <ndn at sqh.me> wrote:
>
>> Hello everyone,
>> I'm using NDN-CCL to writing a NDN application. But I find a problem
>> about data cache.
>> In NDN network ,all data can store in CS.But in my application,some
>> content always changing in 5 seconds,so I think setting a freshnessSecond
>> will help me solve this problem.
>> I try to setMustBefresh value,but it not works.The app also receive the
>> cached value.
>> But in NDN-CCL,I didn't find any method to set this?how to set it?
>>
>> hope you give me some reply.
>>
>> thanks.
>>
>> _______________________________________________
>> Ndn-interest mailing list
>> Ndn-interest at lists.cs.ucla.edu
>> http://www.lists.cs.ucla.edu/mailman/listinfo/ndn-interest
>>
>>
> Please correct me if I'm wrong, but it sounds like you're trying to ensure
> the retrieving application always gets the latest data.
>
> "Must be fresh" tells NDN nodes to to return Data that have not yet
> expired. Data with a freshness period of 5 seconds will satisfy a "must be
> fresh" Interests for 5 seconds. The timer is with respect to when the Data
> arrived at the node.
>
> Depending on the details of your application, you can try a couple things:
>
>   1. Set a conservative freshness period (e.g. 1 second).  This will
> result in more Interests reaching the publisher, but mitigate stale Data
> retrieval.
>   2. Minimize the freshness period (e.g. 0 ms) so that the content is
> effectively never fresh.
>
> You can combine either approach with the CCL's publisher cache:
> http://named-data.net/doc/ndn-ccl-api/memory-content-cache.html . Your
> application can insert Data packets into this application content cache and
> then query it as Interests arrive. Note, you may need to set the cleanup
> timer value to something big to prevent it from removing the technically
> stale Data packets. However, this should simplify the publisher's
> implementation and keeping your consumers up to date.
>
> Hope that helps,
> Steve
>
>
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