[Vm-dev] Re: Stream Control Transmission Protocol

Ben Coman btc at openinworld.com
Thu Aug 6 13:06:43 UTC 2015


On Thu, Aug 6, 2015 at 2:12 AM, Holger Freyther <holger at freyther.de> wrote:
>
>> On 05 Aug 2015, at 19:59, Ben Coman <btc at openinworld.com> wrote:
>
> Hi,
>
>
>> Going through old issues, I see one [1] regarding adding SCTP [2]
>> support.  I've not heard of this protocol before. What are its
>> benefits and use case for Pharo/Squeak?
>
> SCTP was designed by the telecommunication community to migrate
> from systems using MTPL2/MTPL3. I am not going into the benefits
> of SCTP itself but this protocol is the base for “SIGTRAN” and also
> for backend systems in LTE networks. It was considered for things like
> WebRTC as well.
>
>
>> Regarding our resource constraints, modularisation goal and ongoing
>> support, what is our strategy for this?
>
>> 1. Integrate for Pharo 5?
>
> no
>
>
>> 2. Integrate into VM as plugin and have as external Configuration for
>> image?  (btw, remind me if a Configuration can also add a VM plugin?)
>
> no
>
>
>> 3. Continue to leave it for later?
>
> I am not sure. I think there should be two separate items:
>
> * The SocketPlugin should know the SCTP network type and operations
> like socket(2)/connect(2)/bind(2) should work. The beauty of the BSD
> socket design is that the VM only needs to know how to deal with a
> filedescriptor.
>
> * There should be an additional plugin to bind the advanced sctp primitives.
> This could work on OSX, FreeBSD and Linux.
>

So it seems you only need VM changes integrated. How would you feel
about working directly with the vm-dev community to do this?  A ticket
in the Pharo bugtracker is implicitly waiting for someone else to pick
it up and push it, but Pharo has only a few busy people to work on the
VM, thus your ticket there has languished >2yrs.  There are more
non-Pharo vm-devs (who don't follow the Pharo bug tracker), so going
direct you might have a broader chance of getting it reviewed and
integrated.  This might not have been so practical when you first
logged your ticket since at that time the Pharo-VM had diverged from
the mainline-Cog-VM but its now realigned to get all the Spur
goodness, so Pharo would inherit your changes in due course.

Full disclosure: I'm trying to close old tickets to reduce our
software inventory [1] - but I hopefully this is a good path for you
also.
[1] http://www.joelonsoftware.com/items/2012/07/09.html

cheers -ben


>
>> 4. Decline to use it?
>
> Then I have to find different kind of work. :)
>
>
>> Holger, What application are you using this for, and how are you
>> managing to work with this at the moment?
>
> I am using a piece of C application that handles SCTP/SIGTRAN and
> provides a TCP/IP relay for Pharo.
>
>


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