Re: DSDV in ns-2.1b5

[Youngbae - Ko <youngbae@cs.tamu.edu>]

On Thu, 8 Jul 1999, Satish Kumar wrote:

> 
> I havent used dsdv and so I dont know what exactly the problem might be. Abt 
> addressing, the default in ns is 16 bit addrs with the last 8 bits being the 
> port number. So when you see iph->src_ = 255, it actually means node 0 with 
> port 255 (which is the ROUTER_PORT for dsdv). So node 1 would be 511 and so 
> on. BTW, if you have more than 128 nodes in your scenario, you need to expand 
> the address space (using set-address-format expanded; see Chapter 14 in ns 
> Doc). Hope this is of some help.
> 
> Satish
> 

Satish:
Yes, it is very helpful to me. :)

BTW, I have checked on the routing table of node 2 
when there are two nodes: node 1 and node 2. 
(Note that node 0 does not exist in a generated scenario file.)

Now, once node 2 gets a routing update from node 1 initially,
node 2's routing table looks like this:

 ### dest   : 1
 ### hop    : 255
 ### metric : 1
 ### seqnum : 4
 ===================================
 ### dest   : 2
 ### hop    : 2
 ### metric : 0
 ### seqnum : 0
 ===================================

By your explanation of addressing (255 = node 0 with a port 255), 
the hop value (255) for dest (1) in the table above is wrong?
should be 511 ?? (If so, it seems a bug.)

- Youngbae



> 
> > On Thu, 8 Jul 1999, Satish Kumar wrote:
> > 
> > > 
> > > You might want to check if the AgentTrace, RouterTrace or MacTrace Tcl 
> > > variables are set to ON in the wireless.tcl example file.
> > 
> > Thanks, Satish
> > But, I had set to ON for all Traces in the wireless.tcl file. 
> > Therefore, I don't think that is the reason for my problem.
> > 
> > One thing I suspect is that a routing table would have wrong information.
> > I tried to make a printout elements of a routing table and 
> > I found that some garbage values were stored in the routing table. 
> > For example, a next hop field (rte.hop) is set by 255.
> > 
> > Have you looked at the 'dsdv.cc' file?  
> > In the 'makeUpdate()' function on that file, there is a statement:
> > 
> >           :
> >   rte.dst = myaddr_;
> >   rte.hop = iph->src_;    <--- Is this correct ?? 
> >   rte.metric = 0;              (It is 255 initially and seems to be      
> >           :                     increased by 256 - (into 511, 767...)
> >  
> > 
> > - Youngbae
> > 
> > 
> > 
> > > > Hello.
> > > > 
> > > > I need some help from whoever have tested on dsdv routing 
> > > > implementation (CMU's extensions) in the current version of ns-2.
> > > > 
> > > > I have tried to execute ns-2 for cbr traffics with a DSDV 
> > > > routing agent ( tcl/mobility/dsdv.tcl and dsdv/dsdv.cc files ). 
> > > > I have used my own scenario and connection files.
> > > > I really suspect that this DSDV version works properly.
> > > > 
> > > > 1) Nothing is in a output trace file (out.tr), except for movement 
> > > >    of nodes (M). Looks no data packets go through the network.
> > > > 
> > > > 2) some bugs at functions to handle routing table update ??
> > > > 
> > > > It is surprising if the DSDV does not work because CMU folks
> > > > reported a simulation result using DSDV routing agent in their paper.
> > > > Anyone who have experienced similar problems with dsdv, 
> > > > please answer for me. 
> > > > 
> > > > regards,
> > > > - Youngbae
> > > > 
> > > > /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
> > > >      Young-Bae Ko    {youngbae@cs.tamu.edu}
> > > > 
> > > >      http://www.cs.tamu.edu/people/youngbae
> > > >      Dept. of Computer Science   [Tel] 409-845-5007 
> > > >      Texas A&M University        [Fax] 409-847-8578
> > > > /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
> > > > 
> > > 
> > > 
> > > 
> > 
> > 
> > /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
> >      Young-Bae Ko    {youngbae@cs.tamu.edu}
> > 
> >      http://www.cs.tamu.edu/people/youngbae
> >      Dept. of Computer Science   [Tel] 409-845-5007 
> >      Texas A&M University        [Fax] 409-847-8578
> > /* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
> > 
> 
> 
> 


/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */
     Young-Bae Ko    {youngbae@cs.tamu.edu}

     http://www.cs.tamu.edu/people/youngbae
     Dept. of Computer Science   [Tel] 409-845-5007 
     Texas A&M University        [Fax] 409-847-8578
/* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */