[e2e] UDP length field

Luigi Rizzo luigi at info.iet.unipi.it
Wed Apr 18 12:02:22 PDT 2001

> Again, if UDP needed a length field to deal with that, why didn't TCP?

sounds like the reason is just a trivial one: after source and
destination port and the checksum, there were two spare bytes in
the UDP header to keep the 4-byte alignment, so it sounded natural
to use them for something.
The TCP header size on the other hand was already a multiple of 4
so no spares...


  Luigi RIZZO, luigi at iet.unipi.it  . Dip. di Ing. dell'Informazione
  http://www.iet.unipi.it/~luigi/  . Universita` di Pisa
  TEL/FAX: +39-050-568.533/522     . via Diotisalvi 2, 56126 PISA (Italy)
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