Subject: [Idr] Suresh Krishnan's No Objection on draft-ietf-idr-shutdown-08: (with COMMENT)

From: Suresh Krishnan <[email-masked]>
Date: Tue, 23 May 2017 22:32:19 -0700

Suresh Krishnan has entered the following ballot position for
draft-ietf-idr-shutdown-08: No Objection

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.)

Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html
for more information about IESG DISCUSS and COMMENT positions.

The document, along with other ballot positions, can be found here:
https://datatracker.ietf.org/doc/draft-ietf-idr-shutdown/

----------------------------------------------------------------------
COMMENT:
----------------------------------------------------------------------

Since this notification message is only defined for two of the subcodes,
shouldn't the error handling in Section 4 also check for invalid
subcodes?

Why is the length limited to 128 (instead of the possible 255)? Could be
useful to clarify.

---

From: Job Snijders <[email-masked]>
Date: Thu, 25 May 2017 11:14:02 +0200

On Tue, May 23, 2017 at 10:32:19PM -0700, Suresh Krishnan wrote:
> Since this notification message is only defined for two of the
> subcodes, shouldn't the error handling in Section 4 also check for
> invalid subcodes?

The shutdown communication specification only applies for two of the
subcodes, if another (invalid or valid) subcode is used, the shutdown
communication specification simply does not apply at all, and today's
procedures are used. Some implementations will syslog of a hexdump of
the data received, others silently ignore it, or log an error that an
unknown subcode was used.

> Why is the length limited to 128 (instead of the possible 255)? Could be

The shutdown communication proposal started as a maximum of 128 octet
construct, without a length field:
https://tools.ietf.org/html/draft-snijders-idr-shutdown-00#section-2 the
length field was added later on as suggested by Bruno Decraene to allow
for a form of extendability should we want to define a 'shutdown
communication version 2'. While the length field was added, the shutdown
communication size itself was not increased, hence the length field is
not fully used. 128 is an arbitrary small value.

Kind regards,

Job