question about PDU size

    Hello,


    Great software ! I just have quite some troubles with PDU settings with uncommon modalities.


    I'm trying to find a way to define the max pdu size of the conquest server (it runs under linux), and I can't find any way in the documentation or in the forum... If this is feasible, can you please let me know how to set it ?


    Thanks !


    Best regards,
    jim

    Hello Marecel ;o)


    In fact I have identified similar troubles for two modalities. One was reproducible, in case of large CR studies of 30-50 images, conquest hangs during the c-store process (eg. after 20 images), then afterwards, it's impossible to resend it to conquest. This as a very low frequency, other batchs of large series are processed without any problem, and the server has sufficient RAM... But in production environment this is cannot be accepted...


    It's difficult to find exactly on which side the problem is located, I found a workaround with a gateway put in between where I can set the PDU to 64k and resend it to conquest, but this is a very expensive software...


    Any advice how to progress ?


    The PacsTrouble.log indicates :
    Thu Feb 17 11:55:35 2011 ***VR:ReAlloc out of memory allocating -268361626 bytes


    Thu Feb 17 11:55:35 2011
    ***Client Error: Unknown Command: 0001**
    Thu Feb 17 11:55:35 2011 ***Connection Terminated
    Fri Feb 18 11:57:40 2011 ***VR:ReAlloc out of memory allocating -268361626 bytes


    Fri Feb 18 11:57:40 2011
    ***Client Error: Unknown Command: 0001**
    Fri Feb 18 11:57:40 2011 ***Connection Terminated


    Best regards,
    jim

    Dear Marcel,


    Sorry to come back on this topic I originally started, I still have issues with some specificic modalities, and I'm not always able to reproduce... I tried several times to work with the vendor, but he cannot provide any solution (I talked with the development team also).


    So, in the past I used Conquest 1.4.14 and it looks like the max PDU size is set to 16kb, this is definitely the root cause of the trouble.
    I tried also with 1.4.16k without any progress. As the server is used in a production environment, I cannot play with the system...


    Can you tell me if 1.4.17b could help ? I need to configure Conquest to accept 64kb, this solves all my problems. I have browsed the forum, no luck.


    Again, thanks for the great work !


    Best regards,
    jim

    Hi,


    the value is hardcoded and located such that it is a fairly major change to make it configurable. I can change it and send you a test executable (32 or 64 bits windows) with another hardcoded value easily. There are several fixes in the communication in 1.4.17c which is about to be released. Do you know if there is any downside to changing the value for everyone?


    And what happened when you used 1.4.16k?


    Regards,


    Marcel

    Hi Marcel,


    Thanks for your instant reply !!
    In fact I use the linux version, but anyway I think I need to set up again a server for testing, so ok I can try it on windows (it will be a x64) if this is easier for you.


    It occurs only with the same vendor in case of large batch of 20+ DX images. In the past I tried the 1.14.16k in lab and was not succesful, I don't find back other comments. As a workaround I was only able to solve it by putting a gateway in between, 'just' increasing the PDU. But I'm forced now to find a real fix, I'm ready to dig in :o)


    Why not setting it higher by default ? I googled it and the first answer was "If you have performance issues, set the value higher to make the transfers faster. For example, some modalities prefer a larger PDU size, such as 64K instead of the default 16K" (dcm4che)


    Best regards,
    jim

    Hi,


    Edit: in linux it is easy as you can change the source code yourself. If you download and install linux version 1.4.17c (from the forum) I will post the required changes later today.


    Marcel

    Dear Marcel,


    I have applied the changes as suggested and compiled again, it works fine, I tried a few common modalities and images without any trouble.
    Now I need to check the C-Store from the exotic modality and see the behavior.


    Have a nice day.

    Dear Marcel,
    Switching to maxPDU 64 kb works fine with 1.14.17c ! Using C-Store, I was able to archive two large DX studies that were always rejected by older conquest versions.


    Thanks again !!!

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