Re: [ns] Problem with multicast classifier

[Aaron D Striegel <adstrieg@iastate.edu>]

After further examination, I've narrowed down where the problem is but
I'm still a bit baffled as to why I can't fix the problem.  Near as I can tell,
the reason why that I get a no_slot error is that there is not a classifier
listening for the specific group address that I want.

What is the best way to fix this?  When I tried to use the add-mfc function
in ns-mcast.tcl, I get a run-time error where it cannot find my function
defined for add-rep.  Now, when I examine the function, I see that the
tcl call looks like this:

$multiclassifier_ add-rep $r $src $group $iif

where multiclassifier is in instance of my class.  I get an error saying
it cannot find my function if it is defined as:

Classifier/Multicast/Replicator/DSMCast instproc add-rep { rep src group 
iif } {

However, if I remove the Replicator field, ns finds my function but
now the correct variables are not defined for the function.  Can
anyone who wrote the multicast code help me on this?  The underlying
code is exactly like the BST code but it does not work.  Any assistance
is extremely appreciated.

At 12:23 AM 4/11/2001 -0500, you wrote:
>I'm having some difficulties with the multicast data classifier.  I am 
>trying to implement an encapsulation-based technique whereby replication 
>information is included in the packet instead of in the tcl code.  So far, 
>I have successfully gotten control packets to reproduce in the core.  The 
>problem is that I get an error when trying to reproduce data packets, more 
>so when the reproduced at the next hop:
>
>--- Classfier::no-slot{} default handler (tcl/lib/ns-lib.tcl) ---
>         _o223: no target for slot -1
>         _o223 type: Classifier/Port
>content dump:
>classifier _o223
>         0 offset
>         0 shift
>         2147483647 mask
>         2 slots
>                 slot 0: _o222
>                 slot 1: _o252
>---------- Finished standard no-slot{} default handler ----------
>
>I have two slots installed, namely the multicast classifier, 
>Classifier/Multicast/DSMCast and a LossMonitor.  The problem is that the 
>data packet does not get sent to my recv function for my 
>classifier.  However, my custom DSMCast classifier does catch the packet 
>at the source node (adds the header and replicates the packet).  So, the 
>question I'm wondering is what could cause this and is there anything that 
>I could do to pin the problem down better?
>
>Thanks in advance
>
>Aaron
>
>--------------------------------------------
>Aaron Striegel
>Ph.D. Candidate, Computer Engineering
>Iowa State University
>http://www.public.iastate.edu/~magico

--------------------------------------------
Aaron Striegel
Ph.D. Candidate, Computer Engineering
Iowa State University
http://www.public.iastate.edu/~magico