Re: [Sigtran] Clarify SCTP max packet size.

[Michael Tüxen <Michael.Tuexen at lurchi.franken.de>]

Hi Brian,

sorry, I do not understand what you want to say...

Best regards
Michael

On Jul 7, 2009, at 8:02 PM, Brian F. G. Bidulock wrote:

> Michael,
>
> Err, the MTU SCTP uses when bundling is the Association Path MTU.  It
> subtracts IP header and SCTP header sizes from this Path MTU only when
> considering how many chunks can be bundled.
>
> --brian
>
> Michael Tüxen wrote:                        (Tue, 07 Jul 2009  
> 18:51:09)
> > On Jul 7, 2009, at 8:50 AM, <pierre.allegret at orange-ftgroup.com>
> > <pierre.allegret at orange-ftgroup.com > wrote:
> >
> > > Dear all,
> > >
> > > Just to add with the SCTP bundling feature. If the "SCTP MTU" is
> > > 1500, and the system is bundling messages at the SCTP level, you
> > > should have the risk to segment at the IP level (because of the IP
> > > header). So it is not efficient
> > The MTU SCTP uses is the link layer MTU minus the headers for IP and
> > SCTP.
> > I have not seen an implementation which bundles at the SCTP layer and
> > than
> > needs to fragment at the IP layer. I would consider this broken...
> > > to bundle sctp messages and to segment them at the IP level. Some
> > > vendors limits "SCTP MTU" to avoid that. This is only the Maximum
> > > transmission unit. If one SCTP message to transmit is greater, they
> > > will segment it.
>
> --
> Brian F. G. Bidulock
> bidulock at openss7.org
> http://www.openss7.org/