["Visser, Martin" <martin.visser@xxxxxx>]

You might want to use the approach that Packeteer do on their boxes to
discrimnate between network-induced and server-unduced delay. They have
determined that the initially SYN to SYN-ACK response time fairly well
represents the network part of the delay. This is because for most if
not all modern servers, the initial 3-way handshake is performed by the
the kernel very close to the surface, and pretty much independently of
server CPU load (or other load). Hence if you watch enough new
connections being established between client and server you can get a
good understanding of the network-induced delay. You can then subtract
this delay from the total delay observed in other transactions, say a
HTTP GET, and then get the delay for the server transactional response.

(Clearly ethereal needs to be near the client end - where the connection
is initiated - for this to work.)


Martin Visser

Technology Consultant 
Consulting & Integration
Technology Solutions Group - HP Services

410 Concord Road
Rhodes NSW  2138
Australia 

Mobile: +61-411-254-513
Fax: +61-2-9022-1800     
E-mail: martin.visserAThp.com

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-----Original Message-----
From: ethereal-users-bounces@xxxxxxxxxxxx
[mailto:ethereal-users-bounces@xxxxxxxxxxxx] On Behalf Of Champion, Tim
Sent: Monday, 17 July 2006 9:15 PM
To: Ethereal user support
Subject: RE: [Ethereal-users] Measuring intervals of transfer time

Ethereal allows you to merge multiple capture files so you can easily
when the packet was transmitted and received.

-----Original Message-----
From: ethereal-users-bounces@xxxxxxxxxxxx
[mailto:ethereal-users-bounces@xxxxxxxxxxxx] On Behalf Of Donald Prue
Sent: 14 July 2006 15:58
To: 'Ethereal user support'
Subject: RE: [Ethereal-users] Measuring intervals of transfer time

VAIBHAV,

I would think that the only way to accomplish your time measurement is
to have a sniffer (Ethereal) at each end of the link and they MUST be
time-synced from the same NTP server or else the times are meaningless.
I
hope you can get it done.

Don Prue
Nye County
Manager, Network Operations  
   
dprue@xxxxxxxxxxxx
Desk - 775.751.4266 
Cell   - 775.764.0572 


-----Original Message-----
From: ethereal-users-bounces@xxxxxxxxxxxx
[mailto:ethereal-users-bounces@xxxxxxxxxxxx] On Behalf Of
vaibhav_kaware@xxxxxxxxxxxxxxxx
Sent: Friday, July 14, 2006 12:01 AM
To: ethereal-users@xxxxxxxxxxxx
Subject: [Ethereal-users] Measuring intervals of transfer time

Hi,
I intend to measure the time of transfer of a given packet from source
to the destination. 

But each packet has a single time stamp, that of arrival time on the
client machine. This only marks a single point on the timeline. 

Is it possible to get the duration of travel of the packets using
Ethereal? If yes, how?
Alternatively, is it possible to get the arrival timestamps of the
packets, 'of the other end'?

If not, what could I employ to perform the measurements?

-VAIBHAV

Please read further if further clarification required.
-----------------------------------------------------------
e.g.
If there is a webpage small enough that gets transferred from the server
to the client machine within one packet, then there is no way of knowing
how long it took for the transfer from server to the client, looking
just at the arrival time-stamp on the packet.

e.g.
If a 'file' transfer (download) takes place in 'n>1' number of packets,
then seldom will all the packets arrive in an uninterrupted queue at the
client's machine. In that case, it wont be possible to conclude about
the download time of the 'file' as a whole.

e.g.
When I send a message, say,  using the instant messanger, there is no
way for me to know how much time it took for my message to reach the
other user, as all the timestamps on the packets are the ones that
belong to 'my' machine. What about the arrival time-stamps at the other
end?

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