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
