Re: OPNET - End user experience - Analyzing TCP packets

Abdul,
do you have some digested info on this ? Like what timestamps are there,
who is in charge of setting them, what OSs do support them, etc ?
-Carlos

Abdul @ 02/08/2013 10:36 -0300 dixit:
> TCP timestamping is another option (RFC 1323).
>
> It basically is on OS agnostic relative timestamp that allows for you to
> see when the OS stack actually sent the packet on each side. It allows for
> yet another determinate of latency measurement at each end.
>
> Cool thing is.. its the OS time stamping vs the network timestamp.its a
> clue to how each host is performing at each end.
> On Jul 31, 2013 10:08 AM, "Thomas Perrier" <thomas_at_perrier.name> wrote:
>
>> On Wed, Jul 31, 2013 at 1:21 PM, Carlos G Mendioroz <tron_at_huapi.ba.ar>
>> wrote:
>>> It could do differencial tests between icmp and tcp processing.
>>> Pings are usually answered with very little/no cpu involvement, and
>>> would give a baseline to compare to.
>>
>> The probe could also measure the TCP establishment time
>> (SYN/SYN-ACK/ACK), which would give a baseline for TCP processing time
>> + network latency.
>>
>> -Thomas
>>
>>
>>>>> On Wed, Jul 31, 2013 at 3:06 AM, Sirhan Khan <khan.sirhan_at_gmail.com
>>> wrote:
>>>>>
>>>>>> Hi Guys
>>>>>>
>>>>>> Just a quick question, I just left a meeting now and have been
>> monitoring
>>>>>> packets on wireshark for some time but don't see how this is possible.
>>>>>>
>>>>>> Topology:
>>>>>>
>>>>>> USER -- LAN -- WAN -- OPNET PROBE -- PE -- DATA CENTRE
>>>>>>
>>>>>> Looking at the position of the OPNET probe, can the opnet device look
>> at
>>>>>> the processing time of the USER machine ( how long the client
>> machine's
>>>>>> processor takes to process the tcp packet ).
>>>>>>
>>>>>> According to OPNET, this is possible by looking at certain variables
>> on
>>>>>> the
>>>>>> packet header. Is this possible?
>>>>>>
>>>>>> Regards
>>>>>> Sirhan
>>>>>>
>>>>>>
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>>>>
>>>
>>> --
>>> Carlos G Mendioroz <tron_at_huapi.ba.ar> LW7 EQI Argentina
>>>
>>>
>>> Blogs and organic groups at http://www.ccie.net
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>
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-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
Blogs and organic groups at http://www.ccie.net