[LINK] RFI: Packet
Richard.Chirgwin at informa.com.au
Fri Apr 16 13:03:57 EST 2004
It's quite some time since Rink had a Framewar...
(Sorry. Slow day. When Fed.gov.au suggests Alston for Telstra chairman and
> -----Original Message-----
> From: Glen Turner [mailto:glen.turner at aarnet.edu.au]
> Sent: Friday, April 16, 2004 12:35 PM
> To: Russell Ashdown
> Cc: link at anu.edu.au
> Subject: Re: [LINK] RFI: Packet
> On Fri, 2004-04-16 at 08:29, Russell Ashdown wrote:
> > Drivel: RS-232 (or more correctly in Australia, V.24) is defined at
> > the physical level (or layer one). That level has no concept of a
> > frame.
> Oh dear. The OSI protocol model is defined in ISO 7498-1
> (X.200). That standard doesn't contain the word "frame",
> so I've no idea where you get the notion that the OSI model
> dictates that frames are constrained to any particular OSI
> The OSI Connectionless Mode requires the Link Layer to
> provide a Data-link-service-data-units service, but in
> the most abstract terms:
> The Data Link Layer allows exchange of
> data-link-service-data-units over a data-
> link-connection or exchange of data-link-
> service-data-units (that bear no relation to any
> other data-link-service-data-units) using the
> connectionless-mode data-link-service.
> Conversely, V.24 does use the word "frame", for the
> exact description I gave in my original e-mail.
> And for once, I've got the US government on my side :-)
> Anyway, this is all pedantry. There's the exact definition
> of a "frame" or a "packet" and then there's the highly
> convenient frame/packet/datagram/segment/PDU everyday
> usage of IP network engineers (which obviously breaks
> down under close examination, because it is only a
> convenience). I'd gone to some lengths in my original
> e-mail to distinguish the two usages.
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