Tim,

On Thu, Oct 04, 2018 at 11:42:34PM +0000, Tim Evens (tievens) wrote:
> On 10/4/18, 12:41 PM, "GROW on behalf of Jeffrey Haas" <[email protected] 
> on behalf of [email protected]> wrote:
> >     
> >     :   Depending on BGP peering session type (IBGP, IBGP route reflector
> >     :   client, EBGP) the candidate routes that make up the Pre-Policy Adj-
> >     :   RIB-Out do not contain all local-rib routes.  Pre-Policy Adj-RIB-Out
> >     :   conveys only routes that are available based on the peering type.
> >     :   Post-Policy represents the filtered/changed routes from the 
> > available
> >     
> >     The first one deals with the wording above.  I suspect what is intended 
> > to
> >     be said is effectively that the route considered might not be a BGP 
> > route?
> 
>       In other words, the Adj-RIB-Out Pre-Policy is exactly what would
>       be advertised had there been no egress policy applied. This is
>       peer specific.

This sentence really should go into the draft since it makes it much clearer
what you're intending.

> <Tim> Adj-RIB-Out Pre-Policy should be the routes that would be advertised had
>       there been no egress policy applied.  The question of best, add-paths, 
> ...
>       shouldn’t change this as that would be based on the peering 
> configuration.

So, offering some concrete examples:

Example 1:
- Destination D is the active route.
- Destination D would not be eligible for advertisement to an internal peer
  because it'd loop.
- best-external is configured.
- Backup path B the best external path is advertised.

So, in this situation, you expect B to be advertised sans export policy
being applied as the pre-policy route?

Example 2:
- Add-paths is enabled.
- Destination D1 is the active route.  D2..Dn are add-paths eligible backup
  paths.
- Post-policy, D1..Dn are advertised.

In this situation, what is advertised in pre-policy?

>       There are some folks that are having a hard time with understanding how
>       we take peering configuration into account, but IMO, we (a) can get some
>       of this via the OPEN messages in PEER UP and (b) consider 
> configuration. 

FWIW, I find this point clear.

-- Jeff

_______________________________________________
GROW mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/grow

Reply via email to