[ndnSIM] Some Questions about Content Store

[Alex Afanasyev]

Hi Du,

Word "caching" may not always be the right word to use, since NDN just defines/requires/features a concept of some in-network storage.  This in-network storage can have different forms/tiers, for example it could be 
- a simple packet buffers (short term, acting similar to packet queues in existing IP routers) to facilitate robust recovery from losses: re-expressed Interests don't need to go all the way down to the producer, as they do now
- more sophisticated and longer-term caches (this is what normally meant by "cache")
- permanent data storage (CDN-like storage, "paid by" consumer).

More specifically about ndnSIM.  It is possible to set different limits on ContentStore capacities, as well as different types of ContentStores (including not-yet-implemented "non-caching" ContentStore) on individual simulation nodes.   You can check out example ndn-simple-with-different-sizes-content-store.cc that sets different sizes of ContentStores on different simulation nodes.

---
Alex

On Mar 19, 2013, at 12:55 AM, <duyabo2012 at sina.cn> wrote:

>  
> Hi All ,
> I'm using the ndnSIM to do some experiments ,while I have an idea .
> As we all know that the routers in CCN will cache contant objects they received ,what confused me is whether all or some of the routers have to cache content objects ?
> If every router must install cache policy ,how to solve the redundance of data ? In my opinion we don't need to get data from our neibourhood ,actually three or four steps before we get what we want is acceptable .
> So how about this ,in my university ,four of forty routers will cache content objects ,and the other thirty-six routers are just forwarders between 'consumer who send interest' and 'the four special routers' .
> 
> Thank you in advance .
> 
> Sincerely,
> Du
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