[Nfd-dev] Using Forwarding Hints

[Lixia Zhang]

> On Oct 17, 2019, at 6:02 AM, Philipp Moll <philipp.moll at itec.aau.at> wrote:
> 
> Hi all,
> 
> I wonder if there there is any documentation about using ForwardingHints available? I think I got an idea how everything works by checking out the NFD implementation, but some details are still unclear. Is there additional documentation besides the code?

not sure but I might be the guilty party for the missing of this doc (I vaguely recall I agreed to write something about forwarding hints a few years back, after I had some discussion with Haitao to clarify a couple confusing points, but unfortunately that item is still pretty far down my TODO list)

Unless such a doc existed somewhere else already, otherwise I could take this msg of yours as a starting point, and you could help as well :-)

> In the NFD code, I saw that the forwarding hint is used by forwarding strategies and stripped by the forwarder when the Interest has reached the ProducerRegion.

correct (according to my understanding)

> I also found that the NetworkRegionTable stores the ProducerRegions of the node. It seems that ProducerRegions can be configured statically in the ndf.conf file. Is the nfd.conf file the only possibility to configure ProducerRegions, or is it possible to change it via nfdc as well?

for this, I do not know the answer; need people from NFD management.

> Also, when using NLSR, are the ProducerRegions advertised, or not?

No. Again according to my own understanding, the "ProducerRegion" is simply a property of the local node.

> If there is any additional documentation, or examples available, I would appreciate to get some pointers. So far, I only found the hint that "Specifics of the forwarding logic for Interests with ForwardingHint will be defined in a separated document." on http://named-data.net/doc/NDN-packet-spec/current/interest.html , but no separated document.

I think additional info that might be useful in this doc is how one may get a forwarding hint; there can be a few options, and this doc should show examples.

my 2 cents,
Lixia