Re: [ns] [ns] handoff simulations in mobileip

[kunchanl <kunchanl@pollux.usc.edu>]

What's the error messages you saw when 
you installed ns (what version you used)
and ran the example?


Kun-chan Lan

On Wed, 22 Aug 2001, nicky muhammad ali wrote:

> hi ns users..
> iam using rh 6.2 with intelp 133 mhz
> iam going to make a handoff method in mobile ip simulation
> for my final project in telecommunication engineering. 
> i take study on telecommunication engineering. i am on my
> study for my final project for enginieur/bachelor in
> telecommunication engg. my theme is 'an analysis of seamless
> handoff method in case of mobile ip in the internet cellular
> environment'. 
> 
> iam hoping to using ns for my project, but iam having
> trouble in installing ns and first howto running a
> simple.tcl example.
> ihope u alldont mind to answer this 'stupid' question
> 
> thankyou anyway
> 
> nickymuhammadali
> telecommunicatuion engineering
> stttelkom
> bandung
> indonesia 
> On Tue, 21 Aug 2001 16:17:11 -0700 (PDT)
>  Debojyoti Dutta <ddutta@ISI.EDU> wrote:
> > Hi Huan
> > 
> > We are in the process of adding features to ns that can
> > address the issues
> > that you raised. 
> > 
> > Proceeding from where John left: Suppose you had a very
> > large network with
> > lots of traffic sources and sinks. You want to run the
> > simulations for
> > 4000 seconds. One reason why you may want to run that
> > long would be to
> > find the steady state and find out whether that scenario
> > is interesting
> > for you. That could be done using analytical techniques
> > and would be much
> > faster as the speed of simulations is of the order of the
> > number of
> > packets generated (or events). 
> > 
> > We are working on an architecture that will (within NS)
> > do a quick
> > but approximate analytical simulator that will give you
> > the status of the
> > network in an user friendly fashion. This work is nto
> > available for
> > release as yet. 
> > 
> > If you have any further questions, please let me know. I
> > will try to
> > answer them ....
> > 
> > Regards
> > Debo
> > 
> > -----------------------------------------------------------
> > 
> > 
> > 
> > Hi NS users,
> > 
> > I have searched through NS mailing-list archieve and have
> > found a similar question posted a year ago, but I failed
> > to
> > find an answer for that question. So I re-post this
> > question
> > again, hopefully someone can give me a hint.
> > 
> > http://www.isi.edu/nsnam/archive/ns-users/webarch/2000/msg03604.html
> > 
> > http://www.isi.edu/nsnam/archive/ns-users/webarch/2000/msg03609.html
> > 
> > As I understand, because NS implements a packet-level
> > simulation, the time it takes to run the simulation, and
> > the
> > computer power required is proportional to the number of
> > packets generated. If I want to simulate a big network
> > (many
> > links with large capacity), does it pose a scalability
> > problem for NS ?
> > 
> > Let consider the actual example:
> > 
> > I have just implemented a small simulation to simulate
> > WEB,
> > Audio, and FTP traffic going between Workstation and Node
> > n0, The topology is as following:
> > 
> > 
> > # a Lan consists of 20 workstations
> > # a 10Mbits Switch
> > # a 10Mbits link to outside
> > #
> > #
> > #           n2
> > #         \  |
> > #          \ |
> > #     ... -- n1(Switch) --------- n0
> > #          / |
> > #         /  |
> > #            n21
> > #
> > 
> > If the link utilisation for n1-n0 is 50%, i.e. throughput
> > =
> > 5Mbits equivalent to 500 packets /second  (each packet of
> > about 1Kbytes ~ 10 Kbits). If I run the simulation for
> > 100
> > seconds, since each packet travel through 2 links, NS has
> > to
> > handle a total of 2 * 500 * 100 = 10^5 packets .
> > 
> > The actual time it takes to run on my machine (Pentium
> > III,
> > 700MHz, 256M RAM), is 2 minutes
> > 
> > Now if I want to have a network of 50 routers fully
> > meshed,
> > with links of 10Mbits , and link utilisation = 50% , and
> > run
> > it for 4000 seconds.
> > 
> > Total number of links ~ 50 ^ 2 = 2500
> > Total number of packets generated = 500 * 2500 * 4000 = 5
> > *
> > 10^9 (packets).
> > Expected time to run the simulations = 2(min.)  * 5 *
> > 10^9
> > / (10^5) = 10^5 minutes = 600 (days)
> > 
> > In other words, it is just imposible to run a simulations
> > that generate many traffic. Does anyone have any idea
> > about
> > this.  Pls reply to my address, (and cc NS mailing list
> > if
> > you want to do so). Thank you very much.
> > 
> > 
> > 
> > 
> > 
> 
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