Subject: [OSPF] Alvaro Retana's No Objection on draft-ietf-ospf-encapsulation-cap-06: (with COMMENT)

From: Alvaro Retana <[email-masked]>
Date: Wed, 30 Aug 2017 11:41:27 -0700

Alvaro Retana has entered the following ballot position for
draft-ietf-ospf-encapsulation-cap-06: No Objection

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COMMENT:
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I think there's a normative conflict in these two pieces of text; the first one
from Section 3, and the second from Section 5:

   ...If the Encapsulation Capability
   TLV appears more than once in an OSPF Router Information LSA, only
   the first occurrence MUST be processed and others MUST be ignored.

...

   Any unknown Sub-TLVs MUST be ignored and skipped upon receipt.

   If a Sub-TLV is invalid, its Tunnel Encapsulation TLV MUST be ignored
   and skipped.  However, other Tunnel Encapsulation TLVs MUST be
   considered.

The text from Section 3 says that only the first TLV [*] is to be processed --
but during such processing the receiver may find an invalid sub-TLV, which then
mandates (in Section 5) for other TLVs to be considered.

I think that the easy solution is to change the second "MUST" from Section 3
for a "SHOULD".

It would be nice to describe what is an "invalid" sub-TLV, and that "invalid"
is not the same as "unknown" (right?)...but that an "unknown [tunnel] types are
to be ignored and skipped upon receipt", which would result in processing the
second (if any) TLV.

[*] Benoit's ballot pointed at the need for consistency in the names.