[ih] Date of RFC 791 for celebration

[Noel Chiappa]

    > From: Jack Haverty <jack at 3kitty.org>

    >> On Wed, 2006-03-29 at 09:13 -0500, Noel Chiappa wrote:
    >> So it looks as if my prior take:

    >>> 3 was the first version that had the headers fully split ... but my
    >>> guess is that it included variable-length addresses. I seem to recall
    >>> that 3.1 had the variable-length addresses removed, and 4 was an
    >>> editorial cleanup of 3.1

   .>> is likely accurate (although I wish we could recover a 3.1 spec to be
    >> sure).

    > I don't think it's right to think of 4 as an "editorial cleanup" of 3. 

Ah, I didn't say it was a cleanup of 3, I said it was a cleanup of 3.1! The
two were (I'm fairly sure) very different - TCP/IP-3 had variable-length
addresses, and I'm pretty sure that 3.1 had the fixed-length 4-byte addresses.


TCP/IP 3 really did have variable-length addresses. Here's an excerpt from
IEN-21, "TCP 3 Specification" (which also contains the IP specification); it
says, in section 4.3.1 "Internetwork Packet Format":

  An address is a variable length quantity (in multiples of octets). It is
  intended for the first octet of an address to be interpreted as a network
  identifier, and that the rest of the address identifies a host within that
  network.

  ...


    DAL: 4 bits
	Destination Address Length in octets.
    SAL: 4 bits
	Source Address Length in octets.
    Destination: variable
	The destination address, DAL octets in length.
    Source: variable
	The source address, SAL octets in length.

Figure 4.3-1 in that document shows this all too.

	Noel