file transmission speed

[7554753]

i have a question. While i am using the storescp to receive the .dcm files in the server. The transfer speed is much lower than i am directly copying the files to the server. How can i fully use the network bandwidth, or how can i transfer the file as much faster as i am directly copying the file?

[7554753]

i mean use dicomSender tools to send hunders of files at one time.
Does much of the time is wasted at connecting and disconnecting? And how can i solve this problem in the storescp source code?

[Marco Eichelberg]

The answer to your question depends very much on how you are using storescp, and on the sending tool (storescu). Make sure that you

• run storescp in --bit-preserving mode
• use the latest snapshot and not DCMTK 3.5.4 release if you are using storescu as a sender
• Send all images using a single call to storescu, not a separate call for each image, which would cause a separate network connection to be negotiated each time

There is still one bottleneck in the DICOM network protocol, that is, the C-STORE-RSP messages that need to be sent by storescp after each incoming image. A further speed-up would be possible if the so-called asynchronous window negotiation would be supported both by the sender and by the user - this permits the sender to start sending the second image befor the acknowledge for the first image has been received and processed and thus de-couples both directions of transmission. This, however, requires non-trivial changes in the implementation of both sender and receiver.

[7554753]

Then how to changes the receiver or storescp, do you mean i can only process received images one by one?
I just want to save the received images' information into database. if i can only process one image eacn time, that means i'll waste much in connecting database.

[Marco Eichelberg]

The policy of how many images are transmitted in a single network connection is defined by the client (SCU), not by the server. The server receives incoming objects and needs to acknowledge each receipt with a C-STORE-RSP message. Other than that, the local behaviour of the receiver is not mandated by the standard, i.e. is largely implementation specific.

[7554753]

Thanks for your answer.
If i transmit 100 images in a single network connection, the storescp will generate 1 C-STORE-RQ message or 100 C-STORE-RQ messages?

[Michael Onken]

Hi,

for transmitting 100 images, exactly 100 C-STORE-RQ messages are being transmitted in DICOM, in DCMTK's case from _storescu_ to storescp which again responds with 100 C-STORE-RSP messages. There is no way around that.

You can send all images on one connection (e. g. every start of storescu always starts only one connection = DICOM association); or you could run storescu multiple times to send 100 images on 100 connections which then produces association negotiation overhead.

Regards,
Michael

[7554753]

storescu ScpIP 104 1. dcm 2.dcm
i use the dcmtk scu to send 2 images like above, then the storescu will start one network connection or two network connection? Should I make some changes in storescu source code?

[Jörg Riesmeier]

The answer is one. This is what my colleague meant with "You can send all images on one connection (e. g. every start of storescu always starts only one connection = DICOM association)".