[Tmrg] Traffic Generators (Harpoon and Tmix)

[Lachlan Andrew]

Greetings Sangtae,

On 03/12/2007, SANGTAE HA <sangtae.ha at gmail.com> wrote:
> We have two compelling traffic generators, Tmix[1] and Harpoon[2], one
> of them will be used as a common traffic generator for TCP testing.
> Before deciding which traffic geneator we would go, I list up simple
> comparisons between them. Feel free to update the table.
>
> ----------------------------------------------------------------
>                   Tmix                 Harpoon
> ----------------------------------------------------------------
> TCP/UDP   application-level    application-level
>                  TCP                     TCP/UDP
> ----------------------------------------------------------------
> Model        *(a,b,t) model     inter-arrival time and
>                                          file size distributions
> ----------------------------------------------------------------
> Trace         tcpdump            flow-tool (from routers)
>                  *manual             *manual
> ----------------------------------------------------------------
> Supported   Linux                Linux
>                   FreeBSD          (FreeBSD)
>                   NS2
> ----------------------------------------------------------------
>
> *(a,b,t) = (request size, response size, user think time)
> * "manual" means it supports user-generated vectors or distribution tables
>
> Briefly, Tmix supports more platforms (NS2) while Harpoon includes an
> additional UDP generation.
> After reading the Tmix paper, it looks *(a,b,t) model can represent
> user-interactions better than the model based on inter-arrival and
> file size distributions.

Thanks for checking this out.

I notice that  Tmix  aims to model non-greedy TCP connections.  The
"think times" are not times between user connections, but pauses
within a connection.  Will that make it harder for us to collect
statistics?  If we're measuring things like "file completion time", it
is much harder to define what a "file" is if it is just part of a
long-running non-greedy TCP connection.

Tmix is clearly a more general model, but I personally prefer the
simplicity of considering TCP sources to be greedy.  It simplifies
distinguishing between the effect of slow-start vs normal operation.

Cheers,
Lachlan

-- 
Lachlan Andrew  Dept of Computer Science, Caltech
1200 E California Blvd, Mail Code 256-80, Pasadena CA 91125, USA
Ph: +1 (626) 395-8820    Fax: +1 (626) 568-3603
http://netlab.caltech.edu/~lachlan