Subject: HPR Control Vectors

From: "jim (j.) cobban" <[email-masked]>
Date: Thu, 30 Nov 1995 15:43:00 -0500

I was working on a tool to format out the HPR headers from traces, and I ran
into a small complication.  It appears that HPR has allocated control
vectors using codes which are already in use by other SNA components.  This
does not cause any confusion for the HPR component itself, but it will
complicate writing debugging tools, which do not usually have to worry about
the context in which a particular vector occurs, except where the vector is
explicitly context sensitive.  It must also make the SNA Formats reference a
little confusing.

Most obvious is that the Node Identifier Control Vector (X'00') reuses the
CVID for the SSCP-LU Session Capabilities CV of the ACTLU RSP.

Less obvious, because they are conflicts with the licensed specifications,
rather than with the public portion of SNA are:

  X'03' Network Identifier CV conflicts with SDLC Secondary Station CV
  X'05' Network Address CV conflicts with Channel CV
  X'28' Topic Identifier CV conflicts with Related Session Identifier CV

On the other hand the following vectors were slipped into currently unused
or obsolete slots:

  X'26' NCE Identifier CV
  X'39' NCE Instance CV
  X'61' HPR Capabilities CV
  X'67' ANR Path CV

If these vectors are expected to be context sensitive then they should have
been assigned from the range above X'80'.

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From: "jim (j.) cobban" <[email-masked]>
Date: Fri, 1 Dec 1995 12:37:00 -0500

After sending out my first note concerning the reuse of CVIDs I looked
closer at exactly which CVIDs there was conflict with.  CV X'28' is used by
XRF, which is not currently part of the public specification.  However if we
are actually successful at convincing customers that APPN can replace
existing subarea networks, sooner or later one of them is going to ask about
XRF support in DLUR.  At that point the AIW will have to institute a project
to "publicize" the XRF specification, and then the conflict on this CV will
become an issue.