Are simultaneous associations supported?

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mespak
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Are simultaneous associations supported?

#1 Post by mespak »

Hi,

the documentation refers to a 'multiprocess mode' at a few places, e.g. here:

https://support.dcmtk.org/docs/classDcm ... 6ef9e7d8c7

However, that function is not implemented (nor it's virtual, it's actually a bug), and I do not find examples in the code for handling multiple associations at the same time.

What happens if e.g. multiple clients want to push images to the same store scp at the same time? One is blocked until the other finishes? Or can they both transfer data?

If such asynchronous services are allowed then maybe the event handler (e.g. about association events) should get an argument to identify the association?

Cheers,
Miklos

J. Riesmeier
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Re: Are simultaneous associations supported?

#2 Post by J. Riesmeier »

Did you already check the derived DcmThreadSCP class?

mespak
Posts: 9
Joined: Thu, 2018-02-15, 16:59

Re: Are simultaneous associations supported?

#3 Post by mespak »

Thanks, no, I haven't checked that. So, if I understand well, I can create an SCPPool that will create a new ThreadSCP for each different associations. Nice!

What happens with the "regular" DcmStoreSCP? Can it handle only one association at a time and other association requests will be on hold until the current association ends? Or it can also manage multiple associations, just all of them will be managed by the same instance and the same thread and SCU-s would be blocked only for the time when the SCP is "busy", i.e. sending/receiving commands?

J. Riesmeier
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Joined: Tue, 2011-05-03, 14:38
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Re: Are simultaneous associations supported?

#4 Post by J. Riesmeier »

Thanks, no, I haven't checked that. So, if I understand well, I can create an SCPPool that will create a new ThreadSCP for each different associations. Nice!
A little sample program is also available. Have a look at "dcmnet/tests/tpool.cc".
What happens with the "regular" DcmStoreSCP?
What do you mean: the class DcmStorageSCP or the command line tool storescp?

mespak
Posts: 9
Joined: Thu, 2018-02-15, 16:59

Re: Are simultaneous associations supported?

#5 Post by mespak »

Sorry, I meant DcmScp, indeed. I thought, current DCMTK apps use DcmScp as base class and wanted to know if they can process simultaneous associations. Or if I implement my service based on DcmScp, whether it would be able to process simultaneous requests.

But as I see, it is not actually used in current DCMTK apps, like storescp or dcmqrscp, so it doesn't matter for me in the end. And I can use a thread pool to implement my SCP if I want full concurrency.

Thanks!

J. Riesmeier
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Joined: Tue, 2011-05-03, 14:38
Location: Oldenburg, Germany
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Re: Are simultaneous associations supported?

#6 Post by J. Riesmeier »

For historical reasons, the DcmSCP is not used by the "old" command line tools like storescp or dcmqrscp. However, the newer dcmrecv is based on DcmStorageSCP (which is derived from DcmSCP).

mespak
Posts: 9
Joined: Thu, 2018-02-15, 16:59

Re: Are simultaneous associations supported?

#7 Post by mespak »

Ah, good to know! I haven't seen the dcmrecv and dcmsend commands, either. Thanks.

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