Re: [Sidrops] New Version Notification for draft-sriram-sidrops-drop-invalid-policy-00.txt

[Jeffrey Haas <[e-mail]>]

Sriram,


On Tue, Mar 06, 2018 at 04:34:17PM +0000, Sriram, Kotikalapudi (Fed) wrote:
> We have requested the chairs for time on the SIDROPS meeting agenda to discuss this work:
>  
> https://tools.ietf.org/html/draft-sriram-sidrops-drop-invalid-policy-00 
> 
> The authors would appreciate comments/discussion on the list as well.

I have a concern with one of the terms of your procedure.  From section 3:

:    4.  If selected route is Valid/NotFound, then add the route to Loc-
:        RIB; Else, if Invalid, then add the route to Loc-RIB only if
:        there is no existing route in the Loc-RIB for a subsuming Less
:        Specific prefix.

This sort of thing tries to get periodically added to BGP specs.  In
general, BGP tries *VERY* hard to avoid any sort of cascading dependency
between routes due to the ripple effects.  Enough so that the following is
enshrined in the core spec:

RFC 4271, Section 9.1:

:    The function that calculates the degree of preference for a given
:    route SHALL NOT use any of the following as its inputs: the existence
:    of other routes, the non-existence of other routes, or the path
:    attributes of other routes.

I appreciate what you're trying to do here.  However, my strong advice is
DON'T.

-- Jeff