Re: [Idr] John Scudder's No Objection on draft-ietf-idr-bfd-subcode-04: (with COMMENT)

[Jeffrey Haas <[e-mail]>]

Dale,

On Wed, Jan 04, 2023 at 10:39:24AM -0600, Dale W. Carder wrote:
> In looking at RFC 4486 section 4 which describes usage of 8 other Cease 
> NOTIFICATION subcodes, the majority of those (including administrative
> shutdown) are also SHOULD vs MUST.  It looks like the only MUST for that
> matter is for exceeding prefix limits.
> 
> > Put differently, what language would you want in this document to allow for
> > "choose the best error code given the full knowledge available"?
> 
> When reported up to NMS systems, BFD Down is a leading indicator but to
> me it would be expected that it is correlated with other data by an operator 
> to determine root cause for a session being down.  We see similar issues
> for example when BFD is used with IS-IS. 

BGP gets one thing to put into its NOTIFICATION message.  The BGP
implementation may also lack system-wide knowledge that may be visible in
correlation of other events in the system by a NMS.

The best BGP can do here is "this is the reason I'm choosing to report".

> Dale

-- Jeff