[sctp-dev] Socket Option SCTP_MAXSEG

[Chris Hegarty]

> On 26 May 2016, at 05:19, Amit Bhayani <amit.bhayani at gmail.com> wrote:
> 
> Thanks Chris,
> 
> Is there way to set this at OS level?

Looking at the documentation I don’t see any way to do this at the system
level. Someone on the lksctp mailing list [1] [2] might know better.

> The provider is not accepting any packets greater that 1420 Bytes

This seems strange, the SCTP documentation [3] seems at odds with this:

  "An SCTP receiver MUST be able to receive a minimum of 1500 bytes in
   one SCTP packet.  This means that an SCTP endpoint MUST NOT indicate
   less than 1500 bytes in its initial a_rwnd sent in the INIT or INIT
   ACK."

I assume you are trying to set SCTP_MAXSEG as a workaround to the
issue ( on the receiver side ), rather than attempting to resolve it there?

> and lksctp keeps doing re-transmission which obviously keeps failing. An finally the  link goes down (Abort)

So this looks like a native issue on the receiver side to me, but I do
understand your request for SCTP_MAXSEG support at the Java 
level. Have you confirmed, through a native app, that this resolves
the issue you are seeing? 

I think it would be really useful to bring this up on the lksctp mailing
list [2].  If you do, can you please include me. I am interested in the 
outcome.

> 
> Thanks and Regards,
> Amit. 

-Chris.

[1] linux-sctp at vger.kernel.org
[2] http://lksctp.sourceforge.net
[3] https://tools.ietf.org/html/rfc4960#section-6

> On Thu, May 5, 2016 at 7:28 PM, Chris Hegarty <chris.hegarty at oracle.com> wrote:
> 
> On 5 May 2016, at 12:50, Amit Bhayani <amit.bhayani at gmail.com> wrote:
> 
> > Hi Guys,
> >
> > I am using lksctp with JDK 7 on top. I was looking for SctpScoketOption to set SCTP_MAXSEG, but didn't find it available.
> 
> This option is currently not supported. There is an issue tracking adding
> additional options:
>   https://bugs.openjdk.java.net/browse/JDK-8146626
> 
> -Chris.
>