Re: [Sigtran] [SCTP] Minimum DATA Length possible

Correct, L >= 1.

Best regards
Michael

On Jul 19, 2006, at 1:17 PM, ash kat wrote:

> Hi Michael
>
> Thanks for the response.
>
> Please clarify about the minimum value of L.
> I think it should be 1. Which means that SCTP should not allow the  
> zero byte data in the DATA chunk.
>
> Thanks & Regards,
> Ashwani Kathuria
> FSS India.
>
> Michael Tuexen <[email protected]> wrote:
> Hi,
>
> I'm sending the answer also to TSVWG, where the SCTP related things
> are discussed now...
> draft-ietf-tsvwg-2960bis-02 should be changed to state
>
> A DATA chunk with a user data field of length L will have Length set
> to (16 + L)
> (indicating 16+L bytes).
>
> I consider this editorial.
>
> Best regards
> Michael
>
> On Jul 19, 2006, at 12:35 PM, ash kat wrote:
>
> > Hi All
> >
> > What is the minimum possible length of user DATA which can be sent
> > by SCTP DATA chunk?
> >
> > ------------------------------
> > 1. As per Section 3.3.1 of
> > draft-ietf-tsvwg-2960bis-02
> > ------------------------------
> > " Length: 16 bits (unsigned integer)
> > This field indicates the length of the DATA chunk in bytes from
> > the beginning of the type field to the end of the user data
> > field
> > excluding any padding. A DATA chunk with no user data field
> > will
> > have Length set to 16 (indicating 16 bytes)."
> >
> > This indicate that user data of length zero can be sent by setting
> > "length" field in the DATA chunk to 16, which is the DATA chunk
> > header length. It means no user data in the DATA chunk.
> >
> > However as per
> > ------------------------------
> > Section 3.3.10.9 of
> > draft-ietf-tsvwg-2960bis-02
> > ------------------------------
> >
> > " 3.3.10.9. No User Data (9)
> > Cause of error
> > ---------------
> > No User Data: This error cause is returned to the originator of a
> > DATA chunk if a received DATA chunk has no user data. "
> >
> > So my point is that -
> > If the length field in the DATA chunk Header will be of 16 bytes
> > then there will be no user data in the DATA chunk and when there
> > will be no user data in the DATA chunk the SCTP will returm error.
> > So why it is allowed by SCTP to send DATA chunk with no user data
> > when it is not accepted by the peer SCTP.
> >
> > Thanks & Regards,
> > --Ashwani Kathuria
> > FSS India
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