Cell Relay Archive

[Jerry Mendes <mendes@datacomm-insights.com>]

I had the geography backwards on my previous answer.  It was the Europeans who
were pushing for 32 octet cell length, and Bell Labs and other U.S. interests
wanting 64 octets.  Thanks to Gary Kessler at Hill & Co for remembering better
than I.

Jerry Mendes wrote:

> Too bad no one from Bell Labs responded to this question.  My recollection
> dates from the late 80s, shortly after the ATM cell length had been agreed
> upon through international standards group -- I'm not sure whether it was
> through ISO or CCITT (predecessor of the current ITU-T).  U.S. proposals
> wanted 32 octet cell length, to optimize ATM performance for voice
> networks (hence, Bell Labs interest).  European proposals, driven by
> greater efficiency for data transmission, were written with 64 octet cell
> lengths.
>
> In fact, the 48 octet length was an arbitrary compromise between the two
> as suggested by an earlier poster.  I'd suggest having a look at IEEE
> Communications or IEEE Network magazines from 1987 to 1989 time frame if
> you want to see the discussions.
>
> gro_nospam_@org.chemie.uni-frankfurt.de wrote:
>
> > In article <3725EDCD.11F76A63@xedia.com>, Paul says...
> > >Early on, there were two proposals for cell format, one that had
> > >32 bytes of payload and a 4 byte header, the other 64 bytes of
> > >payload and a bigger header (don't remember the number).  Rather
> > >than do the sensible thing and choose one of those, the committee
> > >doing the work did a "compromise" and picked a number halfway
> > >in between.  That's why there are 48 bytes of payload and 5 bytes
> > >of header.
> >
> > I thought that this was the nice anecdote, the more profane being that
> > SMDS/DQDB uses data blocks of 53 bytes length. Why invent another
> > wheel? The only proof I can provide is the look and feel of the
> > AAL 3/4 - deceptively like SMDS and DQDB ...
> >
> > Anybody having authorative information?
> >
> > Greetings,
> >
> > Peter
> >
> > ... remove _nospam_ from the return address ...

--
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