Re: [IPFIX] [SPAM I AM] RE: MPLS IEs in IANA's IP Flow Information Export (IPFIX) Entities registry

Hi Benoit,

Thanks for the clarification.  I don't really know the RFCs in question and took the previous reply that the interpretation of the bits had changed at face value.

If Exp has effectively always been TC then I also don't see a need to deprecate all of them.

-Andrew

________________________________
From: Benoit Claise [bclaise@cisco.com]
Sent: Thursday, September 11, 2014 2:06 AM
To: Andrew Feren; Gregory Mirsky; ipfix@ietf.org
Subject: Re: [IPFIX] [SPAM I AM] RE: MPLS IEs in IANA's IP Flow Information Export (IPFIX) Entities registry

Two points:
- The EXP bits have been used for QoS mapping for years, even before 2009 (RFC 5462 publication date)
- Do you believe that deprecating/replacing all these IEs will imply that exporter implementations will update their code, just for new ElementID? :-)

I would use the procedure in http://tools.ietf.org/html/rfc7013#section-5.2
Something like:
OLD:

The Label, Exp, and S fields from the label stack entry that was pushed immediately before the label stack entry that would be reported by mplsTopLabelStackSection. See the definition of mplsTopLabelStackSection for further details.

The size of this Information Element is 3 octets.

NEW:

The Label, Traffic Class (previously called Exp in RFC3032<http://www.iana.org/go/rfc3032>), and S fields from the label stack entry that was pushed immediately before the label stack entry that would be reported by mplsTopLabelStackSection. See the definition of mplsTopLabelStackSection for further details.

The size of this Information Element is 3 octets.

And change
- the reference from RFC3032<http://www.iana.org/go/rfc3032> to RFC5462
- the revision +1

Regards, Benoit

Then perhaps the right thing is to deprecate the lot and replace them all.

Thanks,
-Andrew

On 09/10/2014 05:28 PM, Gregory Mirsky wrote:
Hi Andrew,
you’re right, the RFC 5462 changed the interpretation of this field as well (section 2 Details of Change):
2.1<http://tools.ietf.org/html/rfc5462#section-2.1>.  RFC 3032<http://tools.ietf.org/html/rfc3032>

   RFC 3032<http://tools.ietf.org/html/rfc3032> states on page 4:

      3.  Experimental Use

      This three-bit field is reserved for experimental use.

   This paragraph is now changed to:

      3.  Traffic Class (TC) field

      This three-bit field is used to carry traffic class information,
      and the change of the name is applicable to all places it occurs
      in IETF RFCs and other IETF documents.

                Regards,
                                Greg

From: Andrew Feren [mailto:andrewf@plixer.com]
Sent: Wednesday, September 10, 2014 2:25 PM
To: ipfix@ietf.org<mailto:ipfix@ietf.org>
Cc: Gregory Mirsky
Subject: Re: [IPFIX] MPLS IEs in IANA's IP Flow Information Export (IPFIX) Entities registry

Hi Greg,

On 09/10/2014 03:22 PM, Gregory Mirsky wrote:
Dear All,
in several places of describing MPLS Label element IEs the registry still refers to the EXP field even though the RFC 5462 updated RFC 3032 and renamed it “Traffic Class” (TC). Below is the list of IEs that may benefit from updating Description and Reference information:

·         mplsTopLabelStackSection

·         mplsTopLabelStackSection2

·         mplsTopLabelStackSection3

·         mplsTopLabelStackSection4

·         mplsTopLabelStackSection5

·         mplsTopLabelStackSection6

·         mplsTopLabelStackSection7

·         mplsTopLabelStackSection8

·         mplsTopLabelStackSection9

·         mplsTopLabelStackSection10

·         mplsTopLabelExp (should this be deprecated and mplsTopLabelTc be created instead?)

·         postMplsTopLabelExp (should this be deprecated and postMplsTopLabelTc be created instead?)

Did 5462 change just the name from Exp to TC or did the interpretation of the bits change?

-Andrew

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