[Nfd-dev] Expiration time of the RIB entry at the NDN nodes

[Junxiao Shi]

Hi Jongdeog

Which node did the prefix disappear from?

On *producer end host*:
ndnpingserver is supposed to set the expiration time to "never", which
means it should not disappear until ndnpingserver disconnects from local
NFD.

On *Illinois router*:
Auto prefix propagation is supposed to refresh the registration
periodically. The interval is controlled by rib.auto_prefix_propagate.
refresh_interval
<https://github.com/named-data/NFD/blob/c31080d47048eb2598f0f491655d1e6f26d0fa05/nfd.conf.sample.in#L359>
config key.
To diagnose problems in this area, on the end host, set
AutoPrefixPropagator=TRACE loglevel, and you can see whether there is any
failed registrations.


Is your pingserver constantly receiving Interests, or is it mostly idle?
A mostly idle producer would rely on the registration packets to keep the
face alive at router side. A busy producer sends Data to keep the face
alive.


>From Illinois router side, after the prefix has disappeared, do you still
see a face going to the producer end host? Is the FaceId same as the FaceId
when you first start the producer end host?
If the face has disappeared or FaceId has changed, this indicates there has
been no traffic (registration packets or Data) from the producer end host
for longer than face_system.udp.idle_timeout
<https://github.com/named-data/NFD/blob/c31080d47048eb2598f0f491655d1e6f26d0fa05/nfd.conf.sample.in#L116>.
Once the new face (with a new FaceId) is established by a new registration
packet, that registration may be failing (and you'll see why by setting
AutoPrefixPropagator=TRACE loglevel at producer end host) so you don't see
the prefix.


Yours, Junxiao

On Tue, Jan 31, 2017 at 8:47 AM, Lee, Jongdeog <jlee700 at illinois.edu> wrote:

> Dear nfd team,
>
>   Hope all of you are doing fine.
>   I have a question about expiration time of the RIB entry at the NDN
> nodes.
>
>   Suppose that my producer successfully registered one prefix at the
> Illinois node (through auto prefix propagation). And I keep running
> ndnpingserver on the producer side. Empirically, it seems the prefix is
> expired after a day. How can I control the expiration time? If I want to
> register it longer, should I periodically register the prefix?
>
>   Sorry if this question is duplicate.
>
> Best wishes,
> Jongdeog Lee (JD)
>
> ------------------------------------------------
> *Ph.D. Student*
> *Department of Computer Science*
> *University of Illinois at Urbana-Champaign*
>
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