Subject: [Bier] Adam Roach's No Objection on draft-ietf-bier-mpls-encapsulation-11: (with COMMENT)

From: Adam Roach <[email-masked]>
Date: Wed, 25 Oct 2017 21:04:04 -0700

Adam Roach has entered the following ballot position for
draft-ietf-bier-mpls-encapsulation-11: No Objection

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COMMENT:
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The definition of BSL indicates:

      Note: When parsing the BIER header, a BFR MUST infer the length of
      the BitString from the BIFT-id, and MUST NOT infer it from the
      value of this field.

It then goes on to say:

      The value of this field MUST NOT be set to any value other than
      those listed above.  A received packet containing another value in
      this field SHOULD be discarded, and an error logged.

The expectation that the router is auditing the value of this field raises the
question of whether the router should check if the length indicated by the BFR
field is different than the BFR that corresponds to this packet's BIFT-id.

My suggestion would be to make this consistent: either routers always ignore
the value of this field (even if it is out of range), or routers verify not
just that the value is valid, but that it is in fact accurate.

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I don't see any information in the ballot or the shepherd's write-up discussing
the rationale for having more than five authors on this document. Has this been
discussed with the authors, contributors, and working group already?