Re: Active networking in ns

[Diane Kiwior <dkiwior@tasc.com>]

Hi all,

Sorry that I did not pick up on this thread yesterday.

Guillermo Rodriguez Garcia wrote:

> [I'm forwarding this to the list again]
>
> >I see. In that case, mcast won't help. Have you looked at
this?  They
> >might have fixed classifier.cc in a way that packets
marked as 'active'
> >will be sucked up to the agent level.
> >
> >http://www.tascnets.com/panama/
> >Active Networking Simulation Packages for ns versions
2.1b1 and 2.1b4 are
> >available:
> >     Active Network Package (v-ns2.1b5.tar.gz)
(v-ns2.1b4.tar.gz)
> >     (v-ns2.1b1.tar.Z) for ns:  Files for the LBNL
network simulator ns
> >     version 2 (available for download from LBNL).  The
package include
> >     C++ files that create Active Agents with basic
functionality
> >     (initialization and disabling) and a sample tcl
script that
> >     illustrates this basic behavior.  Directions for
installing the
> >     package can be found in the README file in the
package.
>
> I have been studying this for a while in the past days,
and there
> are only two things about it:
>
> - Although they intended to release this package as a
'generic'
> extension to ns, in fact it is very focused towards AER,
their
> own active protocol; or at least towards active protocols
for
> multicasting.

The basic Active Network Package is designed to allow
multicasting in active
networks so there is some additional overhead in that
respect.

> There is nothing wrong with this, but I want to
> simulate a very large network (2000+ nodes) in which all
the
> nodes may have a built-in data cache (which I am not
modeling
> 'in full' but for which I have to track at least which
> requests are being cached at each node); so I need to keep

> the nodes as simple as possible and remove all unneccesary

> detail.
>
> - Also, this solution involves a modified classifier.cc,
which
> I would like to avoid unless I'm forced to use it (same
reason
> as above).

I don't think there is any way around this without modifying
classifier.  Since
all packets released by an agent in a node pass back through
that node's entry
point, for active networking the entry point must be
modified.   If a packet is
an active packet that has not been seen by the active agent
at that node, it
should be forwarded to the active agent.  If a packet is an
active packet that
has been seen by that node's active agent, it should be
forwarded to the next
hop.  We added two fields to packets and modified
classifier.cc to allow the
entry point to make that decision.

Diane

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Diane Kiwior                            email: dkiwior@tasc.com
TASC, Inc.
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