Network Working Group M. A. Padlipsky
Request for Comments: 962 Mitre-Bedford
November 1985
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TCP-4 Prime
- STATUS OF THIS MEMO
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This memo continues the discussion of a possible transaction oriented
transport protocol. This memo does not propose a standard.
Distribution of this memo is unlimited.
- DISCUSSION
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- In response to Bob Braden's call for a transaction oriented
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- protocol (RFC-955), the following thoughts come to mind:
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- The perceived problem is that connection set-up and tear-down
take too long.
- Other aspects of TCP's reliability/robustness approach are
presumably still desirable.
- We have some spare command bits in the TCP header, and I trust
that there's still a version number field.
- So why not add NYS (no-way handshake) and NIF (graceless close)
commands to TCP and leave everything else as was (except for the
version, of course)?
- Philosophically, that might be somewhat at variance with "the spirit of
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- TCP," but pragmatically it ought to do the trick. Some careful crafting
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- might be required for ISN handling with NYS, but my guess is that if you
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- have to resend the first/possibly only segment you just pretend you're
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- all of a sudden in the middle of SN space (initially you start at the
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- bottom of it) and when it sees the funny ISN the NYS handler knows it
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- should dequeue anything it might have had pending for (re)transmission
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- and start fresh, assuming that if anything gets through to the starting
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- side belatedly it'll get chucked because of being well outside the left
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- edge of the window, if I'm remembering that part right--and please be
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- aware that I'm not bothering to confirm recollections because I don't
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- want to pretend that this is the spec: it's just meant to be the
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- concept, in TV talk. (On the NYS emitting side, presumably you just
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- drop right into ack_expected state--or whatever the right name is--after
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- setting an appropriate bit that'll get you to fiddle the ISN if you take
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- a timeout.) Maybe you even fiddle the ISNs more elaborately, to allow
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- for several false starts rather than "two strikes and you're out," and
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- maybe we take some spurious segment hits if SNs get suitably balled up,
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- but if you really think handshaking is too expensive then that's the way
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- the premise crumbles.
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- Page 2
- TCP-4 Prime
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- Speaking of graceless closes
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