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Re: Classifier and Routing?
Sun,
here's what i've been able to understand from ns-node.tcl and
classifier.h and .cc:
- The same kind of classifier (classifier-address.cc) is used both for
port and address classification.
- This classifier applys a bit shift to the address field to get rid of
either the address or the port #. Then a mask (with a bitwise AND) to make sure
the address (port#) is correctly taken.
- at an ns node the classifier is set-up like this (pretty much):
DA slot
self -> dmux -> agents
n1 -> link1
n2 -> link2
n3 -> link1
for a topology, say, like this:
n2---------n0--------n1-------n3
link2 link1
Where dmux is a port classifier (an address classifier with a shift&mask
to get the port #).
I hope that clarifies it, and if i have made mistakes people on the list
can correct me (please do so).
Sincerely,
Tarik.
> From: K Sun <[email protected]>
> To: Tarik Alj <[email protected]>
> cc: [email protected]
> Subject: Re: Classifier and Routing?
> Date: Sat, 2 Oct 1999 22:21:14 +0100 (GMT Daylight Time)
> X-Authentication: IMSP
> MIME-Version: 1.0
>
> Hello,
>
> > The classifier at a node is filled in ns-node.tcl, Node instproc
> > add-route; wich is called in ns-route.tcl's Simulator compute-flat-routes.
>
> Thanks a lot! In the meantime, I am really sorry that I was not
> careful enough although I wanted. Currently, I know deeplier the
> relation between classifier and routing. Really thank you for your help.
>
>
> > Concerning the classify() function, i 'm also trying to figure it out,
> > particularly the port classification: it seems classification happens on
adress
> > and on port # at the same time?
>
> Yes, it is a problem indeed. According to my understanding,
> classifiation does not happens on address and on port at the same
> time. The slot array of port classifier has been set just after we
> attach an agent to this node. So, the slot array of port classifier
> always keep right. Everytime, Routing just configures the slot array of
> address classifier ( in the Unicast Node). The statement about
> add-route on page 37 gives me such impresssion.
>
>
> > What if I need to access to different headers at
> > the same time to classify?
>
> I do not know this question clearly. Why you need to access to
> different headers at the same time to classifier? I think the routing
> only use address field of a packet.
>
> I really appreciate your help !
>
> Best Regards,
>
> Sun Kai
>
>
>...