[ndnSIM] how to get the transmission delay

Xiaoke Jiang shock.jiang at gmail.com
Thu May 9 23:39:48 PDT 2013 

Hi Alex,
	Is the queueing delay the reason for the difference?  I found that if there were more interests is received at the same time, the transmission delay is larger (no drop packet happened).

	Now I am quite curious on the queueing delay. But http://www.nsnam.org/docs/release/3.16/doxygen/classns3_1_1_drop_tail_queue.html#details presents no parameter of delay.

thanks

My Regards,
Xiaoke Jiang （蒋小可）

Ph.D Candidate,
Dept. of Computer Science and Technology,
Tsinghua University, P. R. China

On May 10, 2013, at 1:39 PM, Alex Afanasyev <alexander.afanasyev at ucla.edu> wrote:

> Hi Xiaoke,
> 
> Propagation delay (time to transmit one bit from one end to another end of the link)  != transmission delay (time difference between putting the first and the last bit of the packet on the wire).  You zeroed the propagation delay, but there is also a finite bandwidth, could be a reason for some delay.  Though I'm not entirely sure why these delays are not equal...
> 
> ---
> Alex
> 
> On May 9, 2013, at 6:57 PM, Xiaoke Jiang <shock.jiang at gmail.com> wrote:
> 
>> Hi Alex, 
>> 	As you describe I install consumer and producer on the same node, and I get all the data back immediately. But if I install them on adjacent nodes, their is time gap between arrival of data.
>> 
>> 	Config::SetDefault ("ns3::PointToPointChannel::Delay", StringValue ("0ms"));
>> 
>> 	I set propagation delay (transmitting on the wire) zero, thus the remained it queue delay. The result is showed in the following. (Interest of Seq 0,1,2,3 is received on the same time)
>> 
>> Time	Node	AppId	SeqNo	Type	DelayS	DelayUS	RetxCount	HopCount
>> 0.008872	0	1	0	LastDelay	0.008872	8872	1	4
>> 0.008872	0	1	0	FullDelay	0.008872	8872	1	4
>> 0.017344	0	1	1	LastDelay	0.017344	17344	1	4
>> 0.017344	0	1	1	FullDelay	0.017344	17344	1	4
>> 0.025816	0	1	2	LastDelay	0.025816	25816	1	4
>> 0.025816	0	1	2	FullDelay	0.025816	25816	1	4
>> 0.034288	0	1	3	LastDelay	0.034288	34288	1	4
>> 0.034288	0	1	3	FullDelay	0.034288	34288	1	4
>> 
>> 
>>  But the bandwidth is enough is carry the traffic, why the queue delay is so large, up to 0.01s.
>> 
>> How to set the queue delay?
>> 
>> thanks
>> 
>> My Regards,
>> Xiaoke Jiang （蒋小可）
>> 
>> Ph.D Candidate,
>> Dept. of Computer Science and Technology,
>> Tsinghua University, P. R. China
>> 
>> On May 10, 2013, at 12:59 AM, Alex Afanasyev <alexander.afanasyev at ucla.edu> wrote:
>> 
>>> If your producer is installed on the same node as the requester, then the requester will get data back "immediately" with 0 delay of simulation time (btw m_transmittedContentObjects 
>>> is just for tracing purposes and doesn't simulate anything).
>>> 
>>> The only reason for consumer's observed delay is due to packet propagation between nodes. That is, time will move forward only when inter-node network operations kick in.
>>> 
>>> ---
>>> Alex
>>> 
>>> On May 9, 2013, at 9:23 AM, Xiaoke Jiang <shock.jiang at gmail.com> wrote:
>>> 
>>>> Hi Alex,
>>>> 	My code as followings:
>>>> 
>>>> 	Interests
>>>> 	for Interest in Interests {
>>>> 		packet = CreateData(Interest)	 
>>>> 	m_protocolHandler (packet);
>>>> 
>>>> 	m_transmittedContentObjects (header, packet, this, m_face);
>>>> 	etc ..
>>>> 	}
>>>> 	
>>>> 	In the above code, the data packet is not answered on the same time, is it?   Since the m_protocolHandler and m_transmittedContentObjects functions will make the timeline forward.
>>>> 
>>>> 	Is there a way to answer all the data packets on the same time?
>>>> 
>>>> thanks
>>>> 
>>>> My Regards,
>>>> Xiaoke Jiang （蒋小可）
>>>> 
>>>> Ph.D Candidate,
>>>> Dept. of Computer Science and Technology,
>>>> Tsinghua University, P. R. China
>>>> 
>>>> On May 10, 2013, at 12:18 AM, Alex Afanasyev <alexander.afanasyev at ucla.edu> wrote:
>>>> 
>>>>> Propagation delay is just a link delay (the one you configure).
>>>>> I forgot to mention the transmission delay which is also simulated by NS-3, and which includes queuing delay and delay placing packet bits on the wire.
>>>>> 
>>>>> ---
>>>>> Alex
>>>>> 
>>>>> On May 9, 2013, at 9:03 AM, Xiaoke Jiang <shock.jiang at gmail.com> wrote:
>>>>> 
>>>>>> Thank you Alex. But what does propagation delay include?
>>>>>> 
>>>>>> thanks
>>>>>> 
>>>>>> My Regards,
>>>>>> Xiaoke Jiang （蒋小可）
>>>>>> 
>>>>>> Ph.D Candidate,
>>>>>> Dept. of Computer Science and Technology,
>>>>>> Tsinghua University, P. R. China
>>>>>> 
>>>>>> On May 10, 2013, at 12:02 AM, Alex Afanasyev <alexander.afanasyev at ucla.edu> wrote:
>>>>>> 
>>>>>>> Hi Xiaoke,
>>>>>>> 
>>>>>>> The delays that are observed by app-delay-tracer include everything you mentioned (queuing delay, propagation delay, which is related to packet size), except processing delay.  This exception comes from the fact that in NS-3 unless you specifically simulate processing delay (which requires additional models), each function call, no matter how complex, is running in zero simulation time.
>>>>>>> 
>>>>>>> ---
>>>>>>> Alex
>>>>>>> 
>>>>>>> On May 9, 2013, at 8:53 AM, Xiaoke Jiang <shock.jiang at gmail.com> wrote:
>>>>>>> 
>>>>>>>> What's more, I am not sure whether the delay includes the router processing time, such as creating PIT entry, Content Store look up , etc.
>>>>>>>> 
>>>>>>>> thanks
>>>>>>>> 
>>>>>>>> My Regards,
>>>>>>>> Xiaoke Jiang （蒋小可）
>>>>>>>> 
>>>>>>>> Ph.D Candidate,
>>>>>>>> Dept. of Computer Science and Technology,
>>>>>>>> Tsinghua University, P. R. China
>>>>>>>> 
>>>>>>>> On May 9, 2013, at 11:33 PM, Xiaoke Jiang <shock.jiang at gmail.com> wrote:
>>>>>>>> 
>>>>>>>>> Hi all,
>>>>>>>>> 	I am trying to get the transmission delay with app tracer. But I am not sure what's concluded in the delay. For example, Queuing time on the router, transmitting time on the wire, etc.
>>>>>>>>> 	Can anyone give me any hints? Thank you in advance.
>>>>>>>>> 	
>>>>>>>>> in my file:
>>>>>>>>>   Config::SetDefault ("ns3::PointToPointNetDevice::DataRate", StringValue ("10Mbps"));
>>>>>>>>>   Config::SetDefault ("ns3::PointToPointChannel::Delay", StringValue ("1ms"));
>>>>>>>>> 
>>>>>>>>> 
>>>>>>>>> And is the delay related to packet size?
>>>>>>>>> 
>>>>>>>>> thanks
>>>>>>>>> 
>>>>>>>>> My Regards,
>>>>>>>>> Xiaoke Jiang （蒋小可）
>>>>>>>>> 
>>>>>>>>> Ph.D Candidate,
>>>>>>>>> Dept. of Computer Science and Technology,
>>>>>>>>> Tsinghua University, P. R. China
>>>>>>>>> 
>>>>>>>> 
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