Subject: Re: [Policy] Re: IP Protocol value range

From: "Robert Moore" <[email-masked]>
Date: Mon, 4 Feb 2002 09:36:04 -0500

>SNAP actually stands for "IEEE 802.1a SubNetwork Attachment Point". See
>http://www.ietf.org/rfc/rfc1483.txt "4.1.  LLC Encapsulation for Routed
>Protocols" for example. The SNAP header includes two fields: OUI (3
>octets) and PID (2 octets).
>
>I have two comments here:
>1. IMO, PCIMe incorrectly describes SNAP as "Sub-Network Access
>Protocol".
>2. Was it intended for the PCIMe class "PolicySNAPVariable" to represent
>only the PID part of the SNAP header (2 octets)? Or should it reflect
>the entire header: OUI+PID (5 octets).

To be honest, I don't know what we meant to refer to with
PolicySNAPVariable.  (I think this class came from Cisco - in
any case, I know it didn't come from IBM.)  Some possibilities:

Currently in PCIMe: Sub-Network Access Protocol.

Mircea's suggestion: IEEE 802.1a SubNetwork Attachment Point.

On acronymfinder.com: Subnetwork Access Protocol,
Standard Network Access Protocol (in bold, for some
reason), Small Network Access Package, and a bunch
of other options that are plainly not what we're
talking about.

Maybe Andrea, or Yoram, or Yoram, or Ron, or John can tell
us what we meant when we defined PolicySNAPVariable.
And maybe they'll even agree! :-)

Regards,
Bob

Bob Moore
Advanced Design and Technology
Application Integration Middleware Division
IBM Software Group
+1-919-254-4436
[email-masked]

---

From: "Mircea Pana"<[email-masked]>
Date: Mon, 04 Feb 2002 10:35:58 -0500

...and just to add to my confusion, RFC1042 defines the *same* SNAP
header as 
"an extension of the LLC header called the Sub-Network Access Protocol
(SNAP)" :-0

So, a reference to the actual definitions (RFC, IEEE etc.) may help if
added in PCIMe. IMO, it is less important what exactly this (or other)
PolicyVariable represents, more important is to define it unambiguously.

Regards,
Mircea.

> Application Integration Middleware Division

_______________________________________________
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From: "Andrew Smith" <[email-masked]>
Date: Mon, 4 Feb 2002 10:50:41 -0800

I don't know where RFC1483 got its material from but SNAP stands for
Sub-Network Access Protocol in all the IEEE documents I've ever seen. It's
defined in IEEE 802 "Overview and Architecture":
http://www.ieee802.org/1/mirror/8021/o-drafts/d29/802-d29.pdf (I think this
URL works for the public) section 10.2.2 is the latest version. You might
also refer to section 10.3 of same document which defines the SNAP encoding,
including the format of the 40-bit "protocol identifier" field.

Note that this document (P802/D29 is the name of the last pre-approval
draft) has been approved by IEEE but I don't think it's available from the
printers yet. If the above URL doesn't work then the old version of the
standard is available at
http://standards.ieee.org/reading/ieee/std/lanman/802-1990.pdf although the
section numbering has changed quite a bit since then.

Andrew Smith

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On Behalf Of
Mircea Pana
Sent: Monday, February 04, 2002 7:36 AM
To: Robert Moore
Cc: [email-masked]; IETF Policy; [email-masked]
Subject: Re: [Policy] Re: IP Protocol value range

Regards,
Mircea.

---

From: "Mircea Pana"<[email-masked]>
Date: Mon, 04 Feb 2002 14:36:06 -0500

Andrew, thanks for the clarification. Looks like rfc1483 was a "red
herring".

A question for the PCIMe authors though: Which part of the SNAP header,
if not all 5 octets, is captured in "PolicySNAPVariable"? If all, then,
I think, the allowed value range should be (0..(2**40-1)) if Integer or
(40 bit) if BitString.

Mircea.