[Ndn-interest] Basic Query about Dual Names for one Content

[Junxiao Shi]

Hi Syed

A properly designed application should use a consistent naming scheme to
access the same content. Choose one of "10pm" and "2200", and stick to it.
If the content is published under two different names, but the network is
not aware of this situation, in-network caching would be ineffective when
the Interest carries a different name.

If the data mule (vehicle) knows the dual name situation, it could respond
to "2200" Interest with "10pm" Data through encapsulation;
Data /vid/sf/breakingnews/20151231/2200/%00%00
  Content=Data /vid/sf/breakingnews/20151231/10pm/%00%00
          Content=news headlines
          signed by breakingnews.com
  signed by vehicle
Encapsulation is necessary because Interest name must be a prefix of Data
name, but breakingnews.com signature is bound to the "10pm" name and the
vehicle does not have breakingnews.com signing key.
Or the response could use redirection:
Data /vid/sf/breakingnews/20151231/2200/%00%00
  Content=REDIRECT to /vid/sf/breakingnews/20151231/10pm/%00%00
  signed by vehicle
Upon receiving this response, the consumer should reexpress the Interest
with "10pm" name.

Yours, Junxiao

On Thu, Jul 21, 2016 at 1:16 AM, Syed Hassan Ahmed <s.h.ahmed at ieee.org>
wrote:

> Thanks Dr. Alex and Prof. Lixia for the replies that actually helped me in
> reshaping my query.
>
> I am foreseeing an example scenario, where we have a vehicle (c) moving
> from San Francisco (location X) to Los Angeles (location Y). Now in this
> new city, a user wants to watch the recent news bulletin on his/her vehicle
> On Board Unit screen. Previously, at location X, the vehicle (c) was using
> hierarchical naming prefixes in the Interest packet to look up and retrieve
> the content, for example:
>
> Unique NONCE: vid/sf/breakingnews/date/10pm/chunk ID... (Interest Type 1)
>
> Now quoting Dr. Alex, "If there are two producers that can serve data
> packets under the same prefix, then forwarding system can choose either of
> them.  If data cannot be retrieved from one, the forwarding may try
> alternative path."
> Will it be okay to assume that globally the name prefixes will be
> identical? For example, at Location Y, the local users are using the
> following prefix to retrieve the same content,
>
> Unique NONCE: vid/sf/breakingnews/date/2200/chunk ID... (Interest Type 2)
>
> Since the vehicle (c) is not aware of this changed prefix, how it can be
> the provider of this content/chunk? Somehow, this vehicle needs to be
> informed about the changed pattern of content prefix. Is the responsibility
> of application then? I see this example, as two different name prefixes for
> the same content.
>
> When this vehicle receives an Interest of Type 2 with a unique Nonce Value
> {to avoid Interest Looping}, due to a different presentation of Time or any
> information within the prefix, vehicle (c) will not be able to forward the
> required Data. If it would be, how?
>
>
>
> Best Regards,
> ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
> *Syed Hassan Ahmed *(하산)
> Kyungpook National University,
> Daegu City, Republic of Korea.
> Cell: +82-10-9883-0786
> https://sites.google.com/site/shahmedknu/
>
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