Re: [Idr] IETF LC for IDR-ish document <draft-ietf-grow-bgp-reject-05.txt> (Default EBGP Route Propagation Behavior Without Policies) to Proposed Standard

[Mikael Abrahamsson <[e-mail]>]

On Tue, 25 Apr 2017, t.petch wrote:

> The current text in RFC 4271 is
> "    If the route is learned from an external peer, then the local BGP
>      speaker computes the degree of preference based on preconfigured
>      policy information.  If the return value indicates the route is
>      ineligible, the route .. "
>
> With this I-D, that becomes
>
> "    If the route is learned from an external peer, then the local BGP
>      speaker computes the degree of preference based on preconfigured
>      policy information.
>
>      If there is no preconfigured policy information, the route is
> ineligible.
>
>                                    If the return value indicates the
> route is
>      ineligible, the route ... "
>
> I think that that is a change that will change what is then transmitted
> on the wire so it is a protocol change.  YMMV.

If you're blackbox-testing a device with this change, you can't tell if 
it's a changed default or if it's got a policy that denies all. There is 
nothing in the on-wire format that has changed. There is nothing changed 
in how the BGP messages are handled in any way, as opposed to a configured 
default DENY-ALL policy in/out.

So I don't see it as a protocol change. It's a default policy change, but 
not a protocol change.

-- 
Mikael Abrahamsson    email: [e-mail]