Re: [Q] Input Queue

[Yuri Pryadkin <yuri@who.isi.edu>]

I think it doesn't work because after your input queue receives the
first packet it blocks and will never unblock again.  If that's the
case, you'll see only one packet getting through.

HoKun Chung <heaven2@knusun.kangnung.ac.kr> writes:

> Hello, ns users.
> I want to implement a input queue.
> but, ns only buit output queue.
> generally, ns consist of following object..
> 
> entry_  =>  classifier  => queue_  => link_  => .....
> 
> |                                     |
> +--------node-----------+
> 
> I modified this structure.
> 
> entry_  => input_queue_  => classifier => queue_  => link_
> |                                                           |
> +--------------- node ----------------+
> 
> But, ns does not work correctly. I modified <ns-node.tcl> file.
> 
> Anyone points out my faults.
> 
> Below is my work.
> -------------------------------------------------------------------
> 
> Node instproc mk-default-classifier {} {
>  $self instvar address_ classifier_ id_ input_queue_ delay_link_
>  set classifier_ [new Classifier/Addr]
>  # set up classifer as a router (default value 8 bit of addr and 8 bit
> port)
>  $classifier_ set mask_ [AddrParams set NodeMask_(1)]
>  $classifier_ set shift_ [AddrParams set NodeShift_(1)]
>  set address_ $id_
> 
>  # 1999.09.09 hokunchung inserted -----------------------------------
>  # insert input Queue
>  set input_queue_ [new Queue/DropTail]
> 
>  # internal delay link
>  set delay_link_ [new DelayLink]
> 
>  $delay_link_ set bandwidth_ 10Mb
>  $delay_link_ set delay_ 5ms
> 
>  $input_queue_ target $delay_link_
>  $delay_link_ target $classifier_
> 
>  # --------------------------------------------------------------
> }
> 
> Node instproc entry {} {
>  if [info exists router_supp_] {
>   return $router_supp_
>  }
>  if ![info exist ns_] {
>   set ns_ [Simulator instance]
>  }
>  if [$ns_ multicast?] {
>   $self instvar switch_
>   return $switch_
>  }
>  $self instvar classifier_ input_queue_
>  # 1999.09.09 hokunchung modified -------------------------------------
>  return $input_queue_
>  #return $classifier_
> }