[sctp-dev] Using SctpMultiChannel

[Chris]

I see now that my reading comprehension isn't so good. So the multi-channel does create new associations also for incoming connections :)

But what I think I would really be after is a connect() method on SctpServerChannel that spawned a new SctpChannel. If so I wouldn't have to go to the multichannel and its somewhat different way of working.

BR,
  Chris

--- On Thu, 8/11/11, Chris <devnullaccount at yahoo.se> wrote:

> From: Chris <devnullaccount at yahoo.se>
> Subject: Re: [sctp-dev] Using SctpMultiChannel
> To: "Johan Lübcke" <johan.lubcke at symsoft.com>, "Chris Hegarty" <chris.hegarty at oracle.com>
> Cc: "sctp-dev at openjdk.java.net" <sctp-dev at openjdk.java.net>
> Date: Thursday, August 11, 2011, 3:13 PM
> Hi Chris and Johan
> 
> big thanks for the replies. 
> 
> I guess I could try send(), but I won't have any data to
> send initially but would like to have the conneciton up so
> it sounds a bit messy compared to my current code. But with
> lack of other options, I'll try it.
> Would the association change be a COMM_UP event with a
> newly-created Association? And I guess that means the
> "attachment" will be null when reaching the handler... 
> 
> Chris Hegarty said:
> > It would appear that you want SctpChannel semantics
> but not
> > the overhead 
> > of creating a new socket for each association. But
> once
> > branched the 
> > returned SctpChannel will be assigned its own socket.
> > 
> 
> Does it? As far as I understood RFC4960, you use the same
> *socket* (since I'm using the same local IP/port) that
> handles multiple different associations. So I'd like a new
> association, which I guess is an SctpChannel but still bound
> to the same socket. But maybe that's what you mean and I'm
> just twisting words :)
> 
> I'm very surprised by the difference between the
> SctpServerChannel and SctpMultiChannel since they are very
> similar in what they do. Could I pervert the
> SctpMultiChannel to do channel.register(OP_ACCEPT) and
> channel.accept() in a similar way as to using "send()" to
> create a connect()? 
> I will need to run a single socket with that can do both
> accept() and connect() on the same port, and currently I'm
> not sure of which of these classes supports that.
> 
> BR,
>   Chris
> 
> 
> 
> --- On Thu, 8/11/11, Chris Hegarty <chris.hegarty at oracle.com>
> wrote:
> 
> > From: Chris Hegarty <chris.hegarty at oracle.com>
> > Subject: Re: [sctp-dev] Using SctpMultiChannel
> > To: "Johan Lübcke" <johan.lubcke at symsoft.com>
> > Cc: "Chris" <devnullaccount at yahoo.se>,
> "sctp-dev at openjdk.java.net"
> <sctp-dev at openjdk.java.net>
> > Date: Thursday, August 11, 2011, 2:59 PM
> > 
> > 
> > On 08/11/11 01:25 PM, Johan Lübcke wrote:
> > > I had the same problem and I ended up doing a
> "send"
> > call to the remote address. That way I get a
> > AssociationChangeNotification with an association id
> that
> > can be passed to "branch".
> > 
> > Yes, this would be the best way to achieve what you
> are
> > looking for.
> > 
> > SctpMultiChannel is a little like a datagram socket,
> in
> > that it can send 
> > and receive messages to/from remote peers without
> > explicitly setting up 
> > an association, i.e. no connect is required. The
> class
> > description and 
> > send method describe this:
> > 
> >    "The channel will implicitly setup a new
> > association whenever it
> >     sends or receives a message from a remote
> > peer if there is not
> >     already an association with that peer."
> > 
> > It would appear that you want SctpChannel semantics
> but not
> > the overhead 
> > of creating a new socket for each association. But
> once
> > branched the 
> > returned SctpChannel will be assigned its own socket.
> > 
> > -Chris.
> > 
> > 
> > > This seems a bit awkward but it works.
> (Especially
> > since I need to have some actual data to send already
> when I
> > want to connect to the remote side). Doing a "connect"
> would
> > have been more natural.
> > 
> > 
> > 
> > >
> > > If there is a better way I am equally
> interested!
> > >
> > >    / Johan
> > >
> > >
> > > 11 aug 2011 kl. 14.03 skrev Chris:
> > >
> > >> Hi,
> > >>
> > >> I'm trying to use SctpMultiChannel to get
> multiple
> > associations on the same socket (same local port/IP
> but
> > different remote endpoints), but I can't for the life
> of me
> > figure out the API (http://openjdk.java.net/projects/sctp/javadoc/com/sun/nio/sctp/SctpMultiChannel.html)
> > >>
> > >> I get that I should do
> SctpMultiChannel.open() to
> > create an instance and that I should bind it to my
> local
> > address(es).
> > >> But then I want to use something like
> connect()
> > (like on a regular SctpChannel), but there's no such
> method,
> > or anything similar as far as I can see. And the only
> way to
> > get a regular SctpChannel out of this class seems to
> be
> > branch(Accociation), but that's not either an option
> since
> > I  need to have an association to call that.
> > >>
> > >> What am I missing?
> > >>
> > >> TIA,
> > >>   Chris
> > >
> >
>