Subject: [trill] Alvaro Retana's No Objection on draft-ietf-trill-p2mp-bfd-08: (with COMMENT)

From: Alvaro Retana <[email-masked]>
Date: Tue, 23 Jan 2018 07:45:58 -0800

Alvaro Retana has entered the following ballot position for
draft-ietf-trill-p2mp-bfd-08: No Objection

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COMMENT:
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(1) The first reference to I-D.ietf-bfd-multipoint appears in Section 5; please
add one in the Introduction when Multipoint BFD is initially mentioned.

(2) I think that using Normative Language (without quotation marks) to mention
what is specified somewhere else can result in confusion as to which is the
authoritative document.  This seems to be the case in Section 4: "If the M bit
of the TRILL Header of the RBridge channel packet containing a BFD Control
packet is non-zero, the packet MUST be dropped [RFC7175]."  The sentence sounds
as if the behavior is specified in rfc7175, but that document says (in Section
3.2 (BFD Control Frame Processing)): "The following tests SHOULD be
performed...Is the M bit in the TRILL Header non-zero?  If so, discard the
frame."  Note that the behavior specified in rfc7175 doesn't use a "MUST".  The
text in this document seems to be used to explain why a new message is needed,
and not in a Normative way -- please clarify the text so that there is no
inconsistency with respect to rfc7175.

(3) Section 5 says that the "processing in Section 3.2 of [RFC7175]
applies...If the M bit is zero, the packet is discarded."  Section 3.2 has that
"SHOULD" that I mentioned above, and it also mentions potential security
issues, which are not referenced in this document.  Are there reasons to keep
the "SHOULD" and not use "MUST" instead (for the p2mp case)?  If the same
semantics as in rfc7175 are kept, then the Security Considerations should
include the concerns.

---

From: "Susan Hares" <[email-masked]>
Date: Tue, 23 Jan 2018 17:40:02 -0500

Alvaro: 
Thank you for the feedback. 
Sue Hares

-----Original Message-----
From: Alvaro Retana [mailto:[email-masked]] 
Sent: Tuesday, January 23, 2018 10:46 AM
To: The IESG
Cc: [email-masked]; Susan Hares; [email-masked]; [email-masked]
Subject: Alvaro Retana's No Objection on draft-ietf-trill-p2mp-bfd-08: (with COMMENT)

When responding, please keep the subject line intact and reply to all email addresses included in the To and CC lines. (Feel free to cut this introductory paragraph, however.)

(1) The first reference to I-D.ietf-bfd-multipoint appears in Section 5; please add one in the Introduction when Multipoint BFD is initially mentioned.

(2) I think that using Normative Language (without quotation marks) to mention what is specified somewhere else can result in confusion as to which is the authoritative document.  This seems to be the case in Section 4: "If the M bit of the TRILL Header of the RBridge channel packet containing a BFD Control packet is non-zero, the packet MUST be dropped [RFC7175]."  The sentence sounds as if the behavior is specified in rfc7175, but that document says (in Section
3.2 (BFD Control Frame Processing)): "The following tests SHOULD be performed...Is the M bit in the TRILL Header non-zero?  If so, discard the frame."  Note that the behavior specified in rfc7175 doesn't use a "MUST".  The text in this document seems to be used to explain why a new message is needed, and not in a Normative way -- please clarify the text so that there is no inconsistency with respect to rfc7175.

(3) Section 5 says that the "processing in Section 3.2 of [RFC7175] applies...If the M bit is zero, the packet is discarded."  Section 3.2 has that "SHOULD" that I mentioned above, and it also mentions potential security issues, which are not referenced in this document.  Are there reasons to keep the "SHOULD" and not use "MUST" instead (for the p2mp case)?  If the same semantics as in rfc7175 are kept, then the Security Considerations should include the concerns.

---

From: Donald Eastlake <[email-masked]>
Date: Wed, 24 Jan 2018 23:22:58 -0500

Hi Alvaro,

On Tue, Jan 23, 2018 at 10:45 AM, Alvaro Retana <[email-masked]>
wrote:

> ...

Sounds reasonable.

> inconsistency with respect to rfc7175.

I think it can be re-worded fairly easily to avoid being normative.

> semantics as in rfc7175 are kept, then the Security Considerations should

I'm pretty sure this was supposed to imply MUST given the inconsistency
with reference to Section 4 as above. The wording is unconditional. It
appears from your point (2) above that the authors were thinking that, in
RFC 7175, the discard if the M bit was "wrong" was a MUST. So I think it
can be changed to use MUST in this draft and that would avoid having to
tweak the Security Considerations.

Thanks,
Donald
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