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

[Job Snijders <[e-mail]>]

On Tue, May 23, 2017 at 10:32:19PM -0700, Suresh Krishnan wrote:
> ----------------------------------------------------------------------
> 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?

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
> useful to clarify.

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