SDP Mail Archive: Re: SDP>PRO Proposal for TIPSI-like protocol

Re: SDP>PRO Proposal for TIPSI-like protocol

Roger K Debry (
Thu, 7 May 1998 08:54:44 -0400

I agree completely with Don. Implementation experience with TIP/SI
and with IPDS over TCP/IP has shown that there is benefit to having
a "packet header".

Roger K deBry
Senior Technical Staff Member
Architecture and Technology
IBM Printing Systems
phone: 1-303-924-4080 on 05/07/98 04:46:54 AM
Please respond to
To: robert.herriot@Eng.Sun.COM
Subject: SDP>PRO Proposal for TIPSI-like protocol

Your assumption might be correct if....

1) 1284.4 was a standard and not just a work in progress
2) 1284.4 was deployed in all parallel environments
3) 1284.4 was deployed in other non-TCP/IP, direct connect environments=

- 1394
- Serial

For the small amount of overhead that a packet header provides, I think=
is worth the price.


* Don Wright *
* Product Manager, Strategic Alliances *
* Lexmark International *
* 740 New Circle Rd *
* Lexington, Ky 40550 *
* 606-232-4808 (phone) 606-232-6740 (fax) *

cc: (bcc: Don Wright)
bcc: Don Wright
Subject: SDP, IPP>PRO Proposal for TIPSI-like protocol

I just finished scanning IEEE 1284.3 and IEEE1284.4. The most interest=
part is Chapter 8 "Service Provider Interface (SPI)" in IEEE 1284.4. T=
chapter describes a "Berkeley Sockets-compatible interface for clients =
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=
issues at that layer.
So, I conclude that we don't need to packetize IPP or do much of what i=
proposed in Roger and Harry's paper. Instead, we can send IPP directly =
sockets layered on top of TCP/IP or 1284.4. There are a few easy-to-so=
issues, such as chunking for document data and intermediate acknowledge=
when attributes are verified for PrintJob. But otherwise IPP stays as i=
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