Re: [802.21] IS Higher Layer Transport Requirements: update on conf call on December 8
Kalyan,
On Thu, Dec 08, 2005 at 02:46:53PM +0100, Kalyan Koora wrote:
> Hi Yoshihiro,
>
> thank you for your reply. Yes, I mean that what you said. As far as I understood the
> .16, they defined default size of lenght filed to be 1 Byte where the MSB is 0 if
> the length of the payload is less than 127. If it is greater than that then the MSB is
> 1 and the 1st byte of the length field indicates, how many bytes are following the
> present length field.
>
> => Result: The size of length field is by default 1 Byte and only on need, it is
> extended further. Well if we think of using TLV format for all services (IS, CS, ES)
> then it is in most cases valid that the "Value" filed, i.e. payload of the IE is (statistically
> seen) less than 127 Byte.
This actually that the length of the Length field is variable as
ASN.1 encoding does. I this this will make TLV implementation
complicated. It is simpler to make it a constant length, say 2-octet.
Yoshihiro Ohba
>
> Hope I put it in correct words.
>
> Regards,
> Kalyan
>
> -----Urspr¸«ängliche Nachricht-----
> Von: Yoshihiro Ohba [mailto:yohba@TARI.TOSHIBA.COM]
> Gesendet: Donnerstag, 8. Dezember 2005 14:34
> An: STDS-802-21@listserv.ieee.org
> Betreff: Re: [802.21] IS Higher Layer Transport Requirements: update on conf call on December 8
>
>
> On Thu, Dec 08, 2005 at 04:07:33AM -0800, Gupta, Vivek G wrote:
> >
> > > - Do you mean with Length = variable, that the size of this field
> > > can
> > be
> > > extended depending on the information sent (like in .16)?
> > [Vivek G Gupta]
> > Yes
>
> I think that Kalyan's question is as to whether the length of the Length field is variable. The length of the Length field should be constant. So the answer should be *No*.
>
> >
> > > I find, having a Length field of 2 Bytes is, in most cases, more
> > than
> > > enough.
> > > i.e., 1 Byte can server the purpose in most of the cases.
> > >
> > [Vivek G Gupta]
> > 1 byte is definitely inadequate. We can go with 2.
>
> Yes, we can go with 2.
>
> Yoshihiro Ohba
>
> >
> > >
> > > With best regards,
> > > Kalyan
> > >
> >
>
>