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NAM/Wired-cum-wireless tutorial.
Hi,
I tried the Wireless tutorial recently added. Everything works
fine except nam for wired-cum-wireless example. Nam gets Segmentation
Fault if I have both wired and wireless node info in the nam file. But the
tutorial says you can see "movement of mobilenodes and traffic in the
wired domain .... traffic flow for mobilenodes is not as yet supported".
If I remove the wireless node related info from the trace file
then the nam works. I even tried with the latest nam snapshot.
Could some one help me?
Thanks a lot,
Muthu
On Thu, 7 Oct 1999, Padmaparna Haldar wrote:
> On Wed, 6 Oct 1999, Mickael Vera wrote:
>
> > ****************************************************************
> >
> > Is it possible to download the tutorial for printing ? I don't know how
> > you
> > generated this tutorial but it would be great to have an html document
> > in a
> > single page.
>
> A tar version of the tutorial can be made available if that is helpful.
> But on the downside, I'm not sure how up-to-date it would be as compared
> to the on-line version.
>
> > Maybe you should say which daily snapshot to use, maybe the date
> > release. It
> > would be a good thing to add identifier to the release of daily
> > snapshots,
> > they are all called ns2.1b6, they could be called ns2.1b6-date.
>
> I think this issue was discussed in ns-users. the process to date-stamp
> daily snapshots is not trivial.
>
> The daily snapshot is the current version for the day and gets updated
> daily. To use the new API discussed in wireless tutorial you can download
> a snapshot from anyday. Just check for validation test results for the day
> (available from ns-page) as these snapshots may sometimes be unstable due
> to ongoing changes made by ns-developers. [will add a line on this in the
> tutorial]
>
> > > X.1.
> Creating a simple wireless scenario > > You use the "val" array variable,
> does the simulation works if I use a > variable > array called "myval" ?
> It is very confusing sometimes that objects uses > global > variables and
> the user doesn't know it. (for example the variable chan > for the >
> base-station in the previous snapshot)
>
> with the new node API in place, global array opt() previously used in
> wireless example scripts is now removed. the use of different names for
> the array (val, opt etc) was especially made to verify this.
> [will clarify this in tutorial]
>
> >
> > Does it work if I change the name "ns_" to "myns" ?
> >
> typically ns_ is used to denote the simulator instance in node movement &
> traffic scenarios used for WL sims.
> in the core ns code, I don't recall use of a global "ns_".
> so yes, it should work as long as the movement and traffic definitions are
> changed accordingly.
>
> > Does it work if I change the name of "tracefd" (it was used by objects
> > some
> > time ago)
> >
> yes.
>
> > What makes the command "set node_($i) [$ns_ node ]" build a mobile node
> > ? Is
> > it just the -adhocRouting option ? Is it possible to create a node that
> > doesn't use any of the adhoc protocols, like a LAN for example ? With
> > the
> > previous version it was possible.
> >
> > If I want to create a wired node after a wireless node how to do ? does
> > "$ns_ node-config" sets default options for the node creation if it has
> > already been called with options?
> >
> > Does the user need to use the "node_" array in the instruction
> > "set node_($i) [$ns_ node ]" ? I think it is used by the node movement
> > scenarios but is it used elsewhere ?
> >
> > No channel is created, where is it created and how do all mobile nodes
> > share
> > the same channel ? Is it possible to have two sets of mobile nodes, each
> > one
> > using its own channel (with this new API) ? It was possible with the old
> > one,
> > I managed to make two sets of dsr nodes with two sets of base stations
> > using
> > MIP (two HA and two FA). How to do thiz now as we don't create channelos
> > anymore ?
>
> Ya Xu has been working on the new APIs; so I'll leave these for him.
>
> > (and you say it is not possible to use a base station with dsr
> > now ?)
>
> At the time of writing tutorial, the process of adding DSR into
> wired-cum-wireless as part of new API was going on.
> [would update tutorial once DSR is in place]
>
> >
> > idem for the prop, only topo is shared by all modes ?
> >
> > node movements : whatif the node leaves the topography ?
> >
> > nodes reset : I think it is to difficult to see that the time at which
> > nodes
> > reset and the one at which ns stops are different, maybe use
> > 150.000000001 and
> > 150.000000002 . Maybe explain why you use such numbers
> >
> to reset nodes before ns exits. [will add this]
>
> > IX.2. Using node-movement/traffic-pattern files and other features in
> > wireless
> > simulations
> >
> > "$god_ set-dist 1 2 2" : How to define the shortest path for several
> > pairs of
> > nodes. What is the default shortest path ?
>
> The node-movement generator "setdest" defines the shortest path using
> random waypoint algorithm for all pairs of nodes in the topology. For ways
> to change these definitions I think it'd be better to direct yr question
> to the CMU grp who created this model. you can mail
> to: [email protected]
>
>
>
> >
> > It would be great to have a better documentation for traces, the one
> > included
> > in the ns Documentation and Notes is not good. The reader has to read
> > C++
> > code, it would be better to have each entry described with all possible
> > values.
>
> We shall be requesting CMU for a better documented trace-support. [will
> add to tutorial].
>
> >
> > X.1. Creating a simple wired-cum-wireless scenario
> ...
> >
> > The variables num_wired_nodes and num_bs_nodes are used only by the user
> > or
> > the ns librairies use them ? Can I not use them at all ?
> >
> yes, you may not.
>
> > ################################################################
> > I think there is not enough documentation about addresses of base
> > stations,...
> [snip]
>
> will elaborate on this and add to tutorial.
>
> >
> > If you could answer me this question, I'd be very pleased.
> > ################################################################
> >
> > After you explained the addresses structures you say to look above for a
> > figure but there is not any figure about addresses.
> >
> I was refering to the topology figure.
>
> > When you create wired nodes, you use this command :
> > "set W($i) [$ns node [lindex $temp $i]]"
> > you should use "ns_" instead of "ns"
> > I don't understand how it can work ?
> > Maybe "ns" is created in a sub-function but it is not a nice behaviour
> > of OTcl
> > about identifiers viewability
>
> that's a typo, sorry. pl refer to the example scripts (wireless*.tcl) in
> these cases as they are relatively free of such errors.
>
> >
> > X.2. Running MobileIP in a simple wired-cum-wireless topology
> >
> ..
> > In a previous version of ns-2.1b6 there was this code :
> > <<
> > ## Default settings
> > set num_wired_nodes 2
> > set num_bs_nodes 2
> > set num_wireless_nodes 3
> > set opt(nn) 5 ;# total number of wireless nodes
> > >>
> >
> > now you write:
> > << set opt(nn) 1 ;# just one MH >>
> >
> > Something has changed, or something is wrong
> >
> value(nn) here denotes the number of mobilenodes (excluding
> base-stations).
>
> > << # note address of MH indicates its in the same domain as HA. >>
> > ^^^
> > Is it necessary to give the mobile node the same address domain as the
> > HA ? (this is not really a question but I think it should be in the
> > tutorial)
> >
> will be covered as mentioned earlier.
>
> > >From the settings of the mobile node destination to the end of the
> > script "ns"
> > is used instead of "ns_"
> >
> typo. see wireless3.tcl.
>
> > It is not possible to download the files wireless*.tcl. (but it was
> > possible
> > earlier today)
> >
>
> there was some problem yesterday in the script that automatically
> updated sym links pointing to the tutorial. this is a temporary glitch and
> should go away by today or tomorrow.
>
> Thanks for yr feedback on the tutorial.
>
> --Padma Haldar.
>
> > I hope you'll answer me,
> >
> > --
> > Vera Mickael Stagiaire
> >
>
> ------------------------------------------------
> Be true to your work, your word, and your friend.
> --Thoreau
>
> Padmaparna Haldar
>