Re: wireless chapter added to Greis' Tutorial

[Sarat Babu Kamisetty <kamisesb@cs.purdue.edu>]

Hi,

Can somebody tell me where this new tutorial is ? I tried
http://www-mash.cs.berkeley.edu/ns/tutorial/index.html that somebody
mailed yesterday. I was able to see the updated tutorial for sometime but
since today morning it says "the requested URL /ns/tutorial/index.html was
not found on this serer". Is it moved to some other place by any chance or
this too has access control ? It would be great if somebody can reply with
the correct URL of this tutorial.

Thanks,
Sarat

On Wed, 6 Oct 1999, Mickael Vera wrote:

> Hi, 
> this mail is addressed to the new maintener of the tutorial.
> 
> It was a very good news to learn that you added these chapters to the
> Tutorial. Sometimes I wonder if the NS team realizes how hard it is to
> understand NS and that there is a real need of documentation as it
> appears
> every day in the mailing list.
> 
> I read your chapters and as you suggest it, I send you my suggestions.
> They
> are not critics and I hope they'll help you to improve your tutorial. I
> told
> you everythnig that may confuses the user (me with my little experience
> of
> wireless in NS) and everything that sould be precised. Many answers may
> be
> found easily but that doesn't mean they shouldn't be in this tutorial.
> 
> There are a lot of suggestions but I found the Tutorial very good !  
> 
> ****************************************************************
> 
> 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.
>  
> It is very good that you give the complete API as it is difficult to
> find it
> elsewhere.
> 
> 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.
> 
> 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)
> 
> Does it work if I change the name "ns_" to "myns" ?
> 
> Does it work if I change the name of "tracefd" (it was used by objects
> some
> time ago) 
> 
> 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) [$ns_ node ]" ? I think it is used by the node movement
> scenarios but is it used elsewhere ? 
> 
> No channel is created, where is it created and how do all mobile nodes
> share
> the same channel ? Is it possible to have two sets of mobile nodes, each
> one
> using its own channel (with this new API) ? It was possible with the old
> one,
> I managed to make two sets of dsr nodes with two sets of base stations
> using
> MIP (two HA and two FA). How to do thiz now as we don't create channelos
> anymore ? (and you say it is not possible to use a base station with dsr
> now
> ?) 
> 
> idem for the prop, only topo is shared by all modes ?
> 
> node movements : whatif the node leaves the topography ?
> 
> nodes reset : I think it is to difficult to see that the time at which
> nodes
> reset and the one at which ns stops are different, maybe use
> 150.000000001 and
> 150.000000002 . Maybe explain why you use such numbers
> 
> IX.2. Using node-movement/traffic-pattern files and other features in
> wireless
> simulations  
> 
> "$god_ set-dist 1 2 2" : How to define the shortest path for several 
> pairs of
> nodes. What is the default shortest path ?
> 
> 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. 
> 
> X.1. Creating a simple wired-cum-wireless scenario 
> 
> Just for information, I used to build base stations with the command 
> create-base-station which could use the dsr routing protocol, this was
> and
> still is the example in ~ns/tcl/example/wired-cum-wireless.tcl. It
> doesn't
> work anymore ? Is that function still used for the base-station ?
> 
> One time you use the val array and opt one. It would be better to always
> use
> the same name.
> 
> 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 ?
>   
> ################################################################
> I think there is not enough documentation about addresses of base
> stations,
> which rules should respect base stations and mobile nodes for their
> respectives addresses and domains ?
> 
> Extract from your Tutorial : 
> "For mixed simulations we need to use hierarchical routing in order to
> route
> packets between wireless and wired domains (see ns Notes&Doc)."
> 
> Extracts from the ns Notes&Doc: 
> << So a node called BaseStationNode is created which plays the role of a
> gateway for the wired and wireless domains. >>
> What are domains ? Is it the same as the 1st number of hierarchical
> addresses
> ? All wired nodes should be in the same domain (address) ?
> 
> << The basestation node is responsible for delivering packets into and
> out of
> the wireless domain.>>
> Which domain, the set of wireless nodes or the address domain number ?
> 
> << Each wireless domain along with its base-station would
> have an unique domain address assigned to them. >>
> A number ?
> 
> 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.
> 
> 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
> 
> X.2. Running MobileIP in a simple wired-cum-wireless topology
> 
> Use of opt() instead of val()
> 
> 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
> 
> << # 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)
> 
> >From the settings of the mobile node destination to the end of the
> script "ns"
> is used instead of "ns_"
> 
> It is not possible to download the files  wireless*.tcl. (but it was
> possible
> earlier today)
> 
> I hope you'll answer me,
> 
> -- 
> Vera Mickael Stagiaire
>