Subject: [sfc] #3 (architecture): Critical Metadata

From: "sfc issue tracker" <[email-masked]>
Date: Tue, 28 Apr 2015 06:18:19 -0000

#3: Critical Metadata

 The document defines two codepoint ranges: one for “critical” (128 to 255)
 and another one “no critical” metadata (0 to 127).

 This terminology is confusing given the “criticality” of a metadata is
 deployment-specific and SFC-specific. Thats is a piece of information may
 be required for a given chain but may not be critical for another one.

 The specification does not explain why there will be mandatory-to-
 implement metadata by design. Shouldn’t this be achieved by configuration
 locally to each SFC-aware element?

 Furthermore, the current text says:

    If a receiver receives an encapsulated packet containing a TLV with
    the Critical bit set in the Type field and it does not understand how
    to process the Type, it MUST drop the packet.  Transit devices MUST
    NOT drop packets based on the setting of this bit.

 Dropping the packet without even sending a notification to the sender or a
 control element is too aggressive IMHO. Such behavior will lead to more
 service degradation when SFC in enabled compared to current service
 deployment schemes.

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 Reporter:                           |      Owner:  draft-ietf-sfc-
  [email-masked]       |  [email-masked]
     Type:  defect                   |     Status:  new
 Priority:  major                    |  Milestone:
Component:  architecture             |    Version:
 Severity:  -                        |   Keywords:
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Ticket URL: <http://trac.tools.ietf.org/wg/sfc/trac/ticket/3>
sfc <http://tools.ietf.org/sfc/>

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From: "sfc issue tracker" <[email-masked]>
Date: Tue, 28 Apr 2015 06:25:00 -0000

#3: Critical Metadata

Changes (by [email-masked]):

 * owner:  [email-masked] => draft-ietf-sfc-
     [email-masked]
 * component:  architecture => nsh

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-------------------------------------+-------------------------------------
 Reporter:                           |       Owner:  draft-ietf-sfc-
  [email-masked]       |  [email-masked]
     Type:  defect                   |      Status:  new
 Priority:  major                    |   Milestone:
Component:  nsh                      |     Version:
 Severity:  -                        |  Resolution:
 Keywords:                           |
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Ticket URL: <http://trac.tools.ietf.org/wg/sfc/trac/ticket/3#comment:1>
sfc <http://tools.ietf.org/sfc/>

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From: "Joel M. Halpern" <[email-masked]>
Date: Tue, 28 Apr 2015 10:36:43 -0400

This is also an NSH quesiton, not an architecture question.  The 
architecture does not define any codepoint ranges.

Yours,
Joel