[ndnSIM] The prefix in the CS
John Baugh
jpbaugh at umich.edu
Mon Jun 12 01:32:52 PDT 2017
Greetings all,
If you wish, ignore the last e-mail unless you have a better suggestion
than me modifying the Consumer base class... I apologize for e-mailing
again so soon, but I did a little digging and found something promising, so
I started playing with it. I won't e-mail again this morning (evening?
night? I don't even know what time it is...)
I modified the Consumer class in ndn-consumer.[hpp,cpp] to maintain an
extra data member, m_suffix, an uint64. I think added an ".AddAttribute"
to the static TypeId definition, so that the helper would allow me to pass
"Suffix" as a helper, with UintegerValue as the type.
Then, in the SendPacket method, I created a condition so that:
* nameWithSequence->appendSequenceNumber(m_suffix) *
is used instead of
nameWithSequence->appendSequenceNumber(seq)
However, now when I run the application:
1. It does print out my prefix/suffix in the form /prefix/%FE%*suffix*
?ndn.InterestLifetime=2000&ndn.Nonce=*someNonceValue*
2. The content store still seems to be caching them as separate content
items! Even if there are say, 20 different requests for /prefix/%FE%01?...
they are each apparently cached separately.
3. Was handling this (2, i.e. duplicate removal/prevention) not
implemented behind the scenes because the seqNumber always ensured the same
item was never requested twice? That seems unrealistic, but I could
understand if simply no one got around to it yet.
*4. Is ensuring duplicates aren't cached something that the Policy must
take care of? (immediately evict an entry with the same /prefix/seqNumber
and/or /prefix/suffix ??*
Thanks a ton for your patience. I'm learning a lot, but apparently have a
long way to go.
Thanks a ton,
John
On Mon, Jun 12, 2017 at 3:05 AM, John Baugh <jpbaugh at umich.edu> wrote:
> Junxiao et al.,
>
> Thank you for your response. That does clarify things a bit. Would the
> best option to, in your words, "program/configure your consumer to send out
> Interests with same names" be to subclass Consumer (or one of its
> subclasses) and override one of the methods?
>
> 1. I cannot seem to find where the randomization of the values such as
> %FE%C3 are being appended to "/prefix/" before the interest is sent. Does
> anyone know where this would be?
>
> 2. I suppose that my goal is to have a particular Consumer object request
> say, /prefix/1 multiple times, maybe interspersed with say, prefix/2 or
> others (but from a finite, reasonably predictable set of options. Thoughts?
>
> 3, I assume if I do (2) even with different Nonces, the producer, cache,
> etc. will consider anything with /prefix/1 to be a single requested content
> object, correct?
>
> 4. I would also assume that it's unlikely the Producer would need
> modified, if you specify that the producer handles "/prefix/" then,
> anything starting with that should be responded to with content, correct?
>
> Thanks,
>
> John
>
> On Tue, Jun 6, 2017 at 2:52 PM, Junxiao Shi <shijunxiao at email.arizona.edu>
> wrote:
>
>> Hi John
>>
>>
>>> When the requested "/prefix" is set for particular consumers, for
>>> example, there appear to be many requests made (e.g., ConsumerCbr):
>>>
>>> /prefix/%FE%C3/...
>>> /prefix/%FE%C4/...
>>>
>>> 1. I printed out the contents of cached items in the Content Store
>>> (using getFullName().toUri() on the iterator in my loop, starting at
>>> begin(), ending at end(), of course.), and noticed that each of these is
>>> treated as separate content objects?
>>>
>>
>> Yes.
>>
>>
>>> 2. I was previously under the impression that /prefix/*whatever* was a
>>> single content object, and that the Content Store wouldn't cache more than
>>> one of them. Is the /%FE%C3/... part of the content object's true name?
>>>
>>
>> Yes.
>>
>>
>>> 3. If this is the case, it seems like the Consumers never request the
>>> same item more than once... is there any way to control this? I want to
>>> ultimately simulate multiple requests of the same contents from various
>>> consumers to see how it affects the Cs
>>>
>>
>> You can program/configure your consumer to send out Interests with same
>> names.
>>
>> Yours, Junxiao
>>
>
>
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