One thing it would buy is a simpler (than 1284.4) way to flow IPP over =
bidi
parallel - no? Isn't this basically what Lexmark has found? I'm confuse=
d why
TIPSI has a packet structure, Lexmark was shipping it on parallel and t=
hen .4
was invented - maybe some background could help (I always thought it wa=
s to
flow SNMP over parallel ;-). If it's true that the .1 packet is only st=
ill
there for legacy I might buy Bob's argument. But I suspect .4 is a much=
more
complex implementation.
Bob, doesn't your proposal say we would have to invent a transport (if =
not
already there) to "IPize" every physical layer (ex. serial)?
Harry Lewis - IBM Printing Systems
owner-ipp at pwg.org on 05/06/98 05:32:34 PM
Please respond to owner-ipp at pwg.org
To: sdp at pwg.org
cc: ipp at pwg.org
Subject: SDP, IPP>PRO Proposal for TIPSI-like protocol
I just finished scanning IEEE 1284.3 and IEEE1284.4. The most interest=
ing
part is Chapter 8 "Service Provider Interface (SPI)" in IEEE 1284.4. T=
his
chapter describes a "Berkeley Sockets-compatible interface for clients =
and
servers to access the services provided by 1284.4".
So if I understand the intent of 1284.4, it is to provide a layer that
supports sockets over parallel connections. All we need to do in IPP is=
reference sockets for TCP/IP and 1284.4 and we don't have to worry abou=
t the
issues at that layer.
So, I conclude that we don't need to packetize IPP or do much of what i=
s
proposed in Roger and Harry's paper. Instead, we can send IPP directly =
on
sockets layered on top of TCP/IP or 1284.4. There are a few easy-to-so=
lve
dangling
issues, such as chunking for document data and intermediate acknowledge=
ment
when attributes are verified for PrintJob. But otherwise IPP stays as i=
s.
If you disagree with my conclusions, I would like to know what the
TIPSI-like packetizing layer provides that sockets don't also provide?
Bob Herriot
=