[ndnSIM] Shortest paths
Chavoosh Ghasemi
chavoosh.ghasemi.off at gmail.com
Fri Sep 7 11:30:33 PDT 2018
Again, you're making an assumtion that you know how we fed link latencies
to the scenario, based on which you decide how to resolve them.
With no priro knowledge about how topology has been set up (e.g. through
AnnotatedTopologyReader or by using Config within the scenario file), how
can we resolve a given point2point channel's latency? That's the question
to answer.
P.S.
> If you use the AnnotatedTopologyReader, you can just set the metric to
the same value as the delay.
I am not sure you are right on this, cause as I remember the last time I
gave it try, it did not work.
Bests,
*- Chavoosh*
On Thu, Sep 6, 2018 at 2:39 PM Klaus Schneider <klaus at cs.arizona.edu> wrote:
>
>
> On 06/09/18 14:16, Chavoosh Ghasemi wrote:
> > This is not general enough to write a patch, as one can define the
> > topology in either way (i.e. through a topology file or Config). Note
> > AnnotatedTopologyReader does not use Config to set up the topology.
>
> Well in this case you can just reuse the value that you set in the
> config file. For example:
>
> > int delayMs = 10
> >
> > PointToPointHelper p2p;
> > p2p.SetChannelAttribute ("Delay", TimeValue (MilliSeconds (delayMs)));
> >
> > fibHelper.AddRoute(node, prefix, face, delayMs);
>
>
>
> > A better solution would be finding the latency of attached links through
> > the node, itself.
>
> Please see the second part of my email:
>
> "Moreover, there's the GetAttribute() function:
> https://www.nsnam.org/docs/manual/html/attributes.html"
>
> So it should look something like this (haven't tested it):
>
> >
> > TimeValue currentDelay;
> > ptpChannel->GetAttribute("Delay", currentDelay);
>
> Best regards,
> Klaus
>
>
>
>
> >
> > On Thu, Sep 6, 2018 at 1:55 PM Klaus Schneider <klaus at cs.arizona.edu
> > <mailto:klaus at cs.arizona.edu>> wrote:
> >
> > If you use the AnnotatedTopologyReader, you can just set the metric
> to
> > the same value as the delay.
> >
> > Here's an example from http://ndnsim.net/current/examples.html
> >
> > >
> > > # link section defines point-to-point links between nodes and
> > characteristics of these links
> > > link
> > >
> > > # Each line should be in the following format (only first two are
> > required, the rest can be omitted)
> > > # srcNode dstNode bandwidth metric delay queue
> > > # bandwidth: link bandwidth
> > > # metric: routing metric
> > > # delay: link delay
> > > # queue: MaxPackets for transmission queue on the link (both
> > directions)
> > > Node0 Node1 1Mbps 1 10ms 10
> > > Node0 Node3 1Mbps 1 10ms 10
> >
> >
> > Moreover, there's the GetAttribute() function:
> > https://www.nsnam.org/docs/manual/html/attributes.html
> >
> >
> > Best regards,
> > Klaus
> >
> >
> >
> > On 06/09/18 11:02, Chavoosh Ghasemi wrote:
> > > Is there any way to get the delay of links?
> > > It seems you cannot get it through PointToPointChannel as GetDelay
> > > method is protected.
> > >
> > >
> > > P.S. The following code does not work
> > > auto t =
> > >
> >
> dynamic_cast<ns3::PointToPointChannel*>(&(*(transport->GetNetDevice()->GetChannel())));
> > > t->GetDelay();
> > >
> > >
> > >
> > > On Wed, Sep 5, 2018 at 2:00 PM Alex Afanasyev <aa at cs.fiu.edu
> > <mailto:aa at cs.fiu.edu>
> > > <mailto:aa at cs.fiu.edu <mailto:aa at cs.fiu.edu>>> wrote:
> > >
> > > It calculates based on the Face "metric", which by default
> > set to 1
> > > for each Face (= incidentally, resulting in hop count). If
> you
> > > update Face metric with latency related metric represented as
> an
> > > integert (unfortunately, we don't have anything that is
> already
> > > available; patches welcome), you will get latency-based
> > calculation
> > > of routes.
> > >
> > > --
> > > Alex
> > >
> > >> On Sep 5, 2018, at 4:47 PM, chavoosh ghasemi
> > >> <chavoosh.ghasemi.off at gmail.com
> > <mailto:chavoosh.ghasemi.off at gmail.com>
> > >> <mailto:chavoosh.ghasemi.off at gmail.com
> > <mailto:chavoosh.ghasemi.off at gmail.com>>> wrote:
> > >>
> > >> Hi,
> > >>
> > >> Apparently, ndnGlobalRoutingHelper::CalculateRoutes() uses
> *hop
> > >> count* as a metric to compute the shortest paths (correct me
> > if I
> > >> am wrong).
> > >> If that's the case, do we have any module (e.g. a helper) in
> > >> ndnSIM that calculates shortest paths based on link latency?
> > >>
> > >> Thanks,
> > >> /- Chavoosh/
> > >>
> > >> --
> > >> /*Chavoosh Ghasemi*/
> > >>
> > >> Ph.D. Student in Computer Networking
> > >> University of Arizona - Computer Science Department*/
> > >> /*
> > >> */Address: Gould-Simpson 721B, /**/1040 E. 4th Street,
> > >> /*
> > >> */ Tucson, AZ 85721
> > >>
> > >> "The /quieter/ you become, the /more you can hear"//*
> > >> _______________________________________________
> > >> ndnSIM mailing list
> > >> ndnSIM at lists.cs.ucla.edu <mailto:ndnSIM at lists.cs.ucla.edu>
> > <mailto:ndnSIM at lists.cs.ucla.edu <mailto:ndnSIM at lists.cs.ucla.edu>>
> > >> http://www.lists.cs.ucla.edu/mailman/listinfo/ndnsim
> > >
> > > ______________
> > > Alex Afanasyev
> > > Assistant Professor, SCIS, Florida International University
> > > 11200 SW 8th Street, PG6 Room 140D, Miami, FL 33199
> > > phone: +1.305.348.4960 (office); email: aa at cs.fiu.edu
> > <mailto:aa at cs.fiu.edu>
> > > <mailto:aa at cs.fiu.edu <mailto:aa at cs.fiu.edu>>
> > > web: https://users.cs.fiu.edu/~afanasyev/
> > <https://users.cs.fiu.edu/%7Eafanasyev/>
> > > <https://users.cs.fiu.edu/%7Eafanasyev/>
> > >
> > >
> > >
> > >
> > > --
> > > /*Chavoosh Ghasemi*/
> > >
> > > Ph.D. Student in Computer Networking
> > > University of Arizona - Computer Science Department*/
> > > /*
> > > */Address: Gould-Simpson 718, /**/1040 E. 4th Street,
> > > /*
> > > */ Tucson, AZ 85721
> > >
> > > "The /quieter/ you become, the /more you can hear"//*
> > >
> > >
> > > _______________________________________________
> > > ndnSIM mailing list
> > > ndnSIM at lists.cs.ucla.edu <mailto:ndnSIM at lists.cs.ucla.edu>
> > > http://www.lists.cs.ucla.edu/mailman/listinfo/ndnsim
> > >
> >
> >
> >
> > --
> > /*Chavoosh Ghasemi*/
> >
> > Ph.D. Student in Computer Networking
> > University of Arizona - Computer Science Department*/
> > /*
> > */Address: Gould-Simpson 718, /**/1040 E. 4th Street,
> > /*
> > */ Tucson, AZ 85721
> >
> > "The /quieter/ you become, the /more you can hear"//*
>
--
*Chavoosh Ghasemi*
Ph.D. Student in Computer Networking
University of Arizona - Computer Science Department
*Address: Gould-Simpson 718, *
*1040 E. 4th Street,*
* Tucson, AZ 85721"The quieter you become, the more you can
hear"*
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