[ns] ERRORS IN LAN

[shailesh sheoran <shailesh@ece.ubc.ca>]

hi,
  i need to attach an errormodel to the LAN i have created. there was some
help available in user archives. i am using following code to insert
errors between two lannodes node(0) and node(1) [my lan consists of only 2
nodes]

proc add-error {lan src dst errmodel} {
        $lan instvar lanIface_

        set nif $lanIface_($dst)
        set filter [new Filter/Field]
        $nif add-receive-filter $filter
        $filter filter-target $errmodel
        $errmodel target [$filter target]
        $filter set offset_ [PktHdr_offset PacketHeader/Mac macSA_]
        $filter set match_ [$src node-addr] # will not work with hier.

}

add-error $lan $node(0) $node(1) $error_mod

but i am getting this error:

 (_o41 cmd line 1)
    invoked from within
"_o41 cmd target"
    invoked from within
"catch "$self cmd $args" ret"
    (procedure "_o41" line 2)
    (SplitObject unknown line 2)
    invoked from within
"$mac_ target"
    (procedure "_o38" line 3)
    (LanIface add-receive-filter line 3)
    invoked from within
"$nif add-receive-filter $filter"
    (procedure "add-error" line 6)
    invoked from within
"add-error $lan $node(0) $node(1) $error_mod"
    (file "errlan.tcl" line 60)


can anyone PLEASE HELP

Shailesh Sheoran
M.ASc. 
Department of Electrical Engineering
University of British Columbia