[Nfd-dev] beforeExpirePendingInterest for forwarding strategy

[Navdeep Uniyal]

Hi Junxiao,

Thank you for the explanation. I am able to trigger the function now.


Best Regards,
Navdeep Uniyal

From: Junxiao Shi [mailto:shijunxiao at email.arizona.edu]
Sent: Mittwoch, 26. August 2015 00:45
To: Navdeep Uniyal
Cc: Steve DiBenedetto; nfd-dev at lists.cs.ucla.edu
Subject: Re: [Nfd-dev] beforeExpirePendingInterest for forwarding strategy

Hi Navdeep

I tried a scenario similar to this.
I have NFD configured as default, except that loglevel for Forwarder,Strategy,BestRouteStrategy2 are set to DEBUG.

In the first experiment, I execute `ndnpeek /A` on the console and wait for it to timeout.
The log lines related to this Interest are:
1440541933.178175 DEBUG: [Forwarder] onIncomingInterest face=261 interest=/A
1440541933.178432 DEBUG: [Forwarder] onContentStoreMiss interest=/A
1440541933.178521 DEBUG: [BestRouteStrategy2] /A?ndn.Nonce=294193691 from=261 noNextHop
1440541933.178585 DEBUG: [Forwarder] onInterestReject interest=/A
1440541933.279071 DEBUG: [Forwarder] onInterestFinalize interest=/A unsatisfied

In the second experiment, I execute `nfdc register /A tcp4://spurs.cs.ucla.edu<http://spurs.cs.ucla.edu>` to create a route toward the prefix, then execute `ndnpeek /A` and wait for timeout.
The log lines related to this Interest are:
1440542132.989179 DEBUG: [Forwarder] onIncomingInterest face=263 interest=/A
1440542132.989297 DEBUG: [Forwarder] onContentStoreMiss interest=/A
1440542132.989376 DEBUG: [Forwarder] onOutgoingInterest face=262 interest=/A
1440542132.989576 DEBUG: [BestRouteStrategy2] /A?ndn.Nonce=2926069994 from=263 newPitEntry-to=262
1440542136.991586 DEBUG: [Forwarder] onInterestUnsatisfied interest=/A
1440542136.991624 DEBUG: [Strategy] beforeExpirePendingInterest pitEntry=/A
1440542136.991649 DEBUG: [Forwarder] onInterestFinalize interest=/A unsatisfied

We can see that the "before expire Interest" trigger is triggered only if the Interest has been forwarded but no Data comes back; it's not triggered if Interest was not forwarded / rejected (in BestRouteStrategy2 it's due to lack of FIB entry).

Not triggering the "before expire Interest" trigger in the first case is a reasonable behavior, because the rejection of this Interest is directly caused by the strategy itself: the strategy is triggered for "after receive Interest" and decides not to forward the Interest, so that forwarding enters the Interest reject pipeline and then finalizes the Interest after the straggler timer. In this situation, the strategy could do whatever it wants within the "after receive Interest" trigger.
In the second case, the "before expire Interest" trigger would inform strategy about an expiring PIT entry, because the unsatisfied Interest is not caused by the strategy: the strategy has forwarded the Interest somewhere, and it should be triggered when Data comes back (in "before satisfy Interest" trigger) or when nothing comes back (in "before expire Interest" trigger).

Yours, Junxiao

On Thu, Aug 20, 2015 at 5:44 AM, Navdeep Uniyal <navdeep.uniyal at neclab.eu<mailto:navdeep.uniyal at neclab.eu>> wrote:
Hi Junxiao,

Below are the client and server configuration which I am using. As none of the files held by server matches with interest, all requests are getting timed out. While overriding the method, currently I am just trying to check if it works, may be later I will include more code as per the requirement.



Client conf:

##########
TrafficPercentage=100
Name=/ndn/nle/file
ExpectedContent=AAAAAAAA
##########


Server Conf:

##########
Name=/ndn/nle/file1
Content=AAAAAAAA
ContentBytes=5000
##########
Name=/ndn/nle/file2
Content=AAAAAAAB
ContentBytes=5000
##########
Name=/ndn/nle/file3
Content=AAAAAAAC
ContentBytes=5000
##########
Name=/ndn/nle/file6
Content=AAAAAAAF
ContentBytes=5000
##########


Method:

void
WeightedLoadBalancerStrategy::beforeExpirePendingInterest(shared_ptr<pit::Entry> pitEntry)
   {
          NFD_LOG_TRACE("Entering beforeExpirePendingInterest"<<pitEntry->getName());
   }




Best Regards,
Navdeep Uniyal

From: Junxiao Shi [mailto:shijunxiao at email.arizona.edu<mailto:shijunxiao at email.arizona.edu>]
Sent: Donnerstag, 20. August 2015 14:36
To: Navdeep Uniyal; Steve DiBenedetto
Cc: nfd-dev at lists.cs.ucla.edu<mailto:nfd-dev at lists.cs.ucla.edu>
Subject: RE: [Nfd-dev] beforeExpirePendingInterest for forwarding strategy


Hi Navdeep



beforeExpirePendingInterest should be triggered when PIT entry is unsatisfied after InterestLifetime.

If you find it’s not triggered, give more details of your setup including the topology and the configuration files of traffic generator server and client.



Yours, Junxiao



From: Navdeep Uniyal
Sent: Thursday, August 20, 2015 05:15
To: Steve DiBenedetto
Cc: nfd-dev at lists.cs.ucla.edu<mailto:nfd-dev at lists.cs.ucla.edu>
Subject: Re: [Nfd-dev] beforeExpirePendingInterest for forwarding strategy


Hi Steve,

Thank you for your reply. I have a doubt regarding the triggering of this event. I am using Ndn Traffic Generator for testing my strategy. I am overriding this method “beforeExpirePendingInterest” just to get some log trace. But I am unable to see anything in the logs. As per my understanding, for all the timed out interests this method should be triggered. Please if you can suggest what could be the potential issue for the method to be not logging anything for the timed out  interest messages.


Best Regards,
Navdeep Uniyal

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.lists.cs.ucla.edu/pipermail/nfd-dev/attachments/20150826/53e2ee7e/attachment.html>