Hi Bruce,
Read chapeter 13 in ns-manual.. I think you are looking for Error Model
instead of Loss Model.
The commands you are using are for wired networks only, if I am not
mistaken.
Bruce Who wrote:
>hi, Ahmad:
>
>======= 2006-04-03 02:05:24 Ahmad Khayyat wrote: =======
>
>
>
>>Hi Bruce,
>>
>>If you enable AGT and RTR tracing (in node-config command in the tcl
>>file), you will see that when a tcp packet is sent out of the RTR layer,
>>its size is larger than its size when sent by the AGT layer. This
>>reflects the fact that the RTR layer adds some headers that contribute
>>to the packet size. The same thing happens when the packet is sent by
>>the MAC layer; it gets a little bigger due to MAC headers.
>>
>>For the inconsistent packet size in the MAC layer between send time and
>>recv time, my guess is that the packet size is measured in the receive
>>event after removing the MAC headers. You will see that the received
>>packet size in the MAC is equal to the packet size sent by RTR, which is
>>the size before adding the MAC headers. Having that said, my guess is
>>that the packet size reported in the send event is the correct size sent
>>out of the MAC layer. In that case, the packet size in the receive event
>>is the size that the MAC layer reports to higher layers.
>>
>>
>
>I agree with you. I find that all beacon/ack packets are exactly 7 bytes.
>I guess this is a bug of ns2?
>
>And I still cannot apply lossmodel to wpan. I modified
>ns-2.29\tcl\ex\wpan\wpan_demo2.tcl this way:
>
>=============================================================
>proc seterrmodel { src dst } {
> global ns_ val node_
> set errmodel [new ErrorModel]
> $errmodel set rate_ $val(per)
> $errmodel set unit_ $val(errUnit)
> eval $ns_ lossmodel $errmodel \$node_($src) \$node_($dst)
>}
>
>...
>
>seterrmodel 0 1
>=============================================================
>
>I added above code into wpan_demo2.tcl, and got the following traceback:
>
>$ ns wpan_demo2.tcl
>num_nodes is set 7
>INITIALIZE THE LIST xListHead
>
>Traffic: ftp
>Acknowledgement for data: on
>invalid command name ""
> while executing
>"$link errormodule $lossobj"
> (procedure "_o3" line 3)
> (Simulator lossmodel line 3)
> invoked from within
>"_o3 lossmodel _o158 $node_(0) $node_(1)"
> ("eval" body line 1)
> invoked from within
>"eval $ns_ lossmodel $errmodel \$node_($src) \$node_($dst)"
> (procedure "seterrmodel" line 7)
> invoked from within
>"seterrmodel 0 1"
> invoked from within
>"if { "$val(traffic)" == "ftp" } {
> puts "\nTraffic: ftp"
> #Mac/802_15_4 wpanCmd ack4data off
> puts [format "Acknowledgement for data: %s" [Mac/8..."
> (file "wpan_demo2.tcl" line 231)
>
>Could anyone give me any clue?
>
>
>
>>Bruce Who wrote:
>>
>>
>>
>>>hi, Ahmad:
>>>
>>>======= 2006-03-31 23:40:43 Ahmad Khayyat wrote: =======
>>>
>>>
>>>
>>>
>>>
>>>>2) assoPermit means whether the node should permit other nodes to
>>>>associate with it so that it becomes their coordinator. Look at the
>>>>802.15.4-2003 standard for details.
>>>>
>>>>5) This is not how LossModel is used. Consult ns-manual for the correct
>>>>usage. It still applies for wpan.
>>>>
>>>>
>>>>
>>>>
>>>Thanks, I'll look into the document.
>>>
>>>And I have another question. This is a snippet from wpan_demo2.tr, I find
>>>that all tcp packets sent out is always 7 bytes bigger than the received
>>>packets. Why do they not have the same size? Then which one(97 or 90) is the
>>>real size of the tcp packets?
>>>
>>>s 11.928192000 _0_ MAC --- 255 tcp 97 [0 5 0 800] ------- [0:2 5:0 30 5]
>>>[133 0] 0 0
>>>s 11.931712033 _5_ MAC --- 255 ACK 5 [0 0 5 0]
>>>r 11.932064067 _0_ MAC --- 255 ACK 5 [0 0 5 0]
>>>r 11.932704033 _5_ MAC --- 255 tcp 90 [0 5 0 800] ------- [0:2 5:0 30 5]
>>>[133 0] 1 0
>>>
>>>
>>>
>>>
>>>
>>>>Bruce Who wrote:
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>>------------------------------------------------------------------------
>>>>>
>>>>>Hi, all:
>>>>>
>>>>>Recently I begin to learn how to use ns2 to run wpan simulations, and
>>>>>stumbled
>>>>>by some problems, hope someone could help me out.
>>>>>
>>>>>1)I found there are some commands like this:
>>>>>eval $ns_ attach-agent \$node_($src) \$udp_($src)
>>>>>
>>>>>why don't we just use this command?
>>>>>
>>>>>$ns_ attach-agent $node_($src) $udp_($src)
>>>>>
>>>>>2) for this command
>>>>>$node sscs startCTDevice <isFFD = 1> <assoPermit = 1> <txBeacon = 0>
>>>>><beaconOrder = 3> <SuperframeOrder = 3>
>>>>>
>>>>>what does assoPermit mean?
>>>>>
>>>>>3) I ran wpan_demo2.tcl and found that all extended addresses of nodes are
>>>>> [0]. Is it necessary to set the address to different values by ourselves?
>>>>>
>>>>>4) I ran "nam wpan_demo2.nam" and found that data stream is only seem
>>>>>between
>>>>> PANCoor(node0) and node1. But we have such statements in the
>>>>> wpan_demo2.tcl
>>>>> script:
>>>>>
>>>>> ftptraffic 0 1 $appTime1
>>>>> ftptraffic 0 3 $appTime3
>>>>> ftptraffic 0 5 $appTime5
>>>>>
>>>>>So why could no communications be seen between node0 and node3/node5?
>>>>>
>>>>>5) And how to set lossmodel for nodes in wpan? I tried following code, but
>>>>>it
>>>>> doesn't work:
>>>>>
>>>>>set loss_module [new ErrorModel]
>>>>>$loss_module set rate_ 0.01
>>>>>$loss_module unit pkt
>>>>>$loss_module ranvar [new RandomVariable/Uniform]
>>>>>$loss_module drop-target [new Agent/Null]
>>>>>eval $ns lossmodel $loss_module \$node_($src) \$node_($dst)
>>>>>
>>>>>Any help would be appreciated! Thanks in advance!
>>>>>
>>>>>
>>>>>
>>>>>Best regards,
>>>>>
>>>>>Bruce Who
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>= = = = = = = = = = = = = = = = = = = =
>>>
>>>Best regards,
>>>
>>> Bruce Who
>>> 2006-04-02
>>>
>>>
>>>
>>>
>>>
>
>= = = = = = = = = = = = = = = = = = = =
>
>Best regards,
>
> Bruce Who
> 2006-04-03
>
>
>
