Cell Relay Archive

[Hui Wang <hwang@akira.hitel.com>]

Thanks for the response. Another related question is,
why is PLCP used for DS1? We have a HP Broadband Testset,
PLCP is the only option for cell generation on physical
layer. It seems ATM Forum likes direct mapping, but 
venders support PLCP, is it a true and why?

Thanks for any response in advance.

Hui
> 
> On Mon, 28 Jul 1997 12:51:53 EDT Hui Wang <hwang@akira.hitel.com> wrote:
> >
> > I am trying to get specs on DS1 over ATM using PLCP. I want to
> > get explicit PLCP format as I have to generate the byte stream
> > myself. The Bellcore specs (GR-1110-CORE, TR-NWT-001112) direct me to
> > IEEE P802.6_DS1_PLCP/D4, which published in 1991. I am wondering
> > if new version is availiable and what's the corresponding
> > ATM Forum standards.
> 
> The IEEE spec for the DS1 PLCP is IEEE Std 802.6c-1993.  It was published in
> an 802.6 supplement in March 1994 (ISBN 1-55937-344-X).  Note, however, that
> the ATM Forum DS1 Physical Layer Specification Version 1.0 (af-phy-0016.000,
> September, 1994) does not call for using the SMDS/802.6 DS1 PLCP to which
> you refer.  Instead a contiguous 1.536 Mbps stream of cells is mapped
> directly into the DS1 payload.  This is done in such a way that octet
> boundaries are preserved, that is, the first payload bit following each
> DS1 framing bit is the first bit of an octet of some cell.
> 
> The ATM Forum recently started keeping approved specs on-line on their
> public ftp server.  The URLs for this spec are:
> 
> ftp://ftp.atmforum.com/pub/approved-specs/af-phy-0016.000.doc  MS Word
> ftp://ftp.atmforum.com/pub/approved-specs/af-phy-0016.000.pdf  Adobe Acrobat
> 
> Additional formats (ps, rtf, txt) may also be available.
> 
> I do know that some vendors (e.g., ADC-Kentrox, in their AAC-1) did support
> PLCP-mapped DS1 ATM at one time, but I don't know if this is still the case.
> Perhaps someone familiar with current products will comment on this.
> 
> Mike
> --
> C. M. Heard/VVNET, Inc.
> heard@vvnet.com
>