Subject: HPR THDR alignment

From: "Ray Bird" <[email-masked]>
Date: Fri, 16 Feb 96 11:20:43 EST

Jim,
  HPR architecture does not require that the THDR begin on a word boundary.
In section A.1.5 it says "if the THDR begins on a word boundary, then all
segments and CVs contained within the THDR will be on word boundaries".
Note the word "if".  The architecture does however require that THDR segments
and CVs be aligned on a word boundary RELATIVE to the beginning of the THDR.
  If a product implementation desires that the THDR begin on a word boundary
then it could adjust the size of its NCE on a per link basis (based on the
link header size) to cause the THDR to fall on a word boundary.  Note that HPR
is currently supported over many different link types (Token Ring, Ethernet,
Frame Relay, SDLC, X.25, PPP) and will be supported over others in the
future (ATM, ISDN, etc.).  It is not reasonable to assume consistency in link
header lengths as a basis for a THDR word boundary alignment.