Problem with 2s delay between SCP SendCStoreResponse() and SCU OnReceiveCStoreResponse()

Today we have experienced delay in dicom communication on XP SP3 32Bit systems over different range of hardware.
We were implementing some new functionality we have only several days to test.
And we have noticed problem with average of 2 seconds delay between:
- calls to (Servers) SCP SendCStoreResponse()
- and event firing on (Clients) SCU OnReceiveCStoreResponse()
But using Windows 7 x64 OS, there was no delay between SCP response and SCU event.

Usually this is not a problem, but in this instance we are using Single Association to send over 200 images where each image has 500kb.
Normally It takes near 100ms per image to complete this task. And whole communication happens extremely fast on development system (without delay).
With this delay on XP SP3 x86 system it takes >2 secs per image to complete this task.
Multiply this figures with 200 and difference is huge : 20 seconds on Win7 x64 and >6 minutes on XP SP3 x86 systems.
6 minutes in our case is simply not acceptable.

We have tested it also with LT17.5 > .NET Class Libraries\.NET Framework\03 Medical\05 PACS (Low Level)\03 Storage SCU
sample application, the problem was the same - XP SP3 x86 systems experience 2s delay in communication.

We have tried almost everything, but behavior is same across all XP SP3 x86 platforms = 2 seconds delay.

Q: have we missed something here???

---

tomorrow we will try to use High Level Dicom Controls.
if any of High Level Controls supports sending multiple DICOM files over single association
(which I recall was the main reason we went with low level implementation).

I tested this issue on my side and the time I've got is 6 milliseconds for single Dicom file. My test was as follows:
- Both leadtools client and leadtools server on the same machine.
- The operating system of the machine is Windows XP SP3 32-bit.
To help you more about this issue, please provide me with the following:
1. Are you using LEADTOOLS client and LEADTOOLS server? Or the Server is non-LEADTOOLS Server?
2. Are both of Client and Server running on the same machine or Different machines? If the answer is Different machines, please send me the Operating system for both machines.
3. Are there additional steps I need to duplicate the issue on my side?

1. Both, dicom server (SCP), and dicom client (SCU) are using Leadtools libraries.
2. Different Machines. Our debug environment consistst of:
- pacs server (SCP) running on Microsoft Server 2008 R2 x64,
- pacs client (SCU) with the issue is running on Microsoft Windows XP SP 3 x86.
3. Only requirement is dicom client capable of sending multiple files over single dicom association. We were testing this with several CT series, approx of 233 images in each. Tested several times with only few images in series issue was the same. All images are around ~ 500kb.


Q: Is there any High Level Control capable of sending multiple dicom datasets over single dicom association?

I am preparing a similar environment so I can test this issue again. I will get back to you with the result of my test. About sending multiple Dicom datasets over one single Dicom association using High Level, yes you may able to do this using our High Level modules, using the Store method of StoreSCU class. Please see this link:
http://www.leadtools.com/help/leadtools/v175/dh/scu/leadtools.dicom.scu~leadtools.dicom.scu.storescu~store%28dicomscp,dicomdataset,boolean%29.html

You can call this method repeatedly and specify TRUE to keep the connection open. When you reach the last dataset, you can specify FALSE to close/terminate the connection.

I tested this issue and I stored 181 MB of Dicom images within 26 seconds so the store rate is approximately is 7 MB/second.
My test is as follows:
1. The PACS client (SCU) demo is on Windows XP SP3.
2. The PACS server (SCP) demo is on Windows 2008 R2 64-bit.

Please note that the version of Leadtools.dll is 17.5.0.62.

If the version number of Leadtools.dll is older than 17.5.0.62, please send a message from a valid email address to support@leadtools.com and include the following:
1. Your toolkit serial number (do NOT post it here).
2. A link to this forum.