[ih] UDP Length Field?

[Noel Chiappa]

    > From: Craig Partridge

    > Recall that the creation of UDP meant TCP and IP had to be split apart

No. The TCP/IP split _long_ predates the creation of UDP. The former is
already apparent as of IEN-21, "TCP 3 Specification" (see pages 56 and 59 for
the IP and TCP header formats), from January 1978. UDP is IEN-71, from
21-Jan-79 (and as I recall, there was not a lengthy discussion before it came
out).

Oh, looking at IEN-71, in the packet format description, it says "data, padded
with zero octets at the end to make a multiple of two octets". So Vint's comment
about the length was right on target.

It mentions host name lookup (_not_ DNS; it was servers which had a copy of
the host table) as the intended appplication. Time was also early, IIRC. My
recollection is that TFTP was the first non-datagra protocol (i.e. not
single-packet transactions) to make use of UDP, but my memory mmay be failing
me there.

   Noel