Re: [Idr] [GROW] draft-snijders-idr-shutdown-00: Drop a line in the peer's syslog at shutdown

[Jeffrey Haas <[e-mail]>]

On Thu, Nov 17, 2016 at 10:57:31AM +0900, Job Snijders wrote:
> On Wed, Nov 16, 2016 at 08:47:01PM -0500, Jeffrey Haas wrote:
> > No new subcodes.
> > Add the text to the NOTIFICATION Data section of existing subcodes, when it
> > makes sense and that Data section isn't otherwise specified.
> 
> What will existing, deployed implementations do if they get trailing
> data after a subcode 2? Can you comment on Juniper JunOS?

In a small number of cases where it understands the contents, e.g. max
prefix, hard reset (long lived graceful restart), unsupported capability, it
will print something useful.  Otherwise, it's Data: <hexdump>.

This behavior is generally useful since it means specs like this can happen
and the contents can happen and you can still get some visibility.  I
heartily recommend the practice.

> 
> Equally:
> 
> What will existing, deployed implementations do if they encounter a
> cease subcode they don't recognise? ExaBGP would emit 'unknow reason'.

Same, displaying the subcode and any Data.

Anyway, my general point is the subcodes have existing semantics.  Use those
as much as makes sense.

-- Jeff