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Re: Bugs in errmodel.cc


> Date:    Fri, 06 Mar 1998 20:18:00 -0500
> From:    Javier Gomez-Castellanos <[email protected]>
> To:      Biaz Saad <[email protected]>
> cc:      John Heidemann <[email protected]>, Gang Xu <[email protected]>,
> 	 [email protected]
> Subject: Re: Bugs in errmodel.cc 
> 
> After fixing the 2 bugs in errmodel.cc, the install-error function 
> defined in ~ns/tcl/ns-lan.tcl is able to create errors on a lan when
> using:
> 
> 	$em target [$channel_ target]
> 	$channel_ target $em
> 
> but not when using
> 
> 	set ll [[$ns_ link $src $dst] link]
> 	$em target [$ll target]
> 	$ll target $em
> 
> has somebody seen the same problem?, thanks 

What kind of problem are you having?  Attaching the error model at the
sending LL might lead to problems if you use time-based error model,
because time can only be obtained after the packet goes through the
channel.  This is why I provided the method install-error for LanLink.
You can call it in 2 ways:

1)	$lan install-error $em
	This is equivalent the first code fragment above.

2)	$lan install-error $em $src $dst
	This will install the error at the receiving interface just
	before the packet gets to the receiving LL.

Giao