Re: draft-ietf-rtgwg-policy-model default reject-route

I agree with the change. 

Thanks,
Yingzhen

> On Sep 27, 2021, at 4:37 PM, Jeff Tantsura <jefftant.ietf@gmail.com> wrote:
> 
> Agree.
> 
> Cheers,
> Jeff
> 
>> On Sep 27, 2021, at 16:20, Chris Smiley <csmiley@amsl.com> wrote:
>> 
>> 
>> Adding rfc-editor@rfc-editor.org
>> 
>> 
>>> On Sep 27, 2021, at 11:58 AM, Acee Lindem (acee) <acee@cisco.com> wrote:
>>> 
>>> Hi Kris, 
>>> I agree with your analysis and proposal. Do others have comment? If not,  we should remove during AUTH48 (Chris Smiley copied). 
>>> Thanks,
>>> Acee
>>> 
>>> On 9/17/21, 10:55 AM, "rtgwg on behalf of Kris Lambrechts" <rtgwg-bounces@ietf.org on behalf of kris@netedge.plus> wrote:
>>> 
>>>  Hi,
>>> 
>>>  I have been working on an implementation of
>>>  ietf-routing-policy@2021-08-12.yang and
>>>  ietf-bgp-policy@2021-07-11.yang and I'm struggling to implement a
>>>  pattern that I think is very common among routing policies.
>>> 
>>>  The problem I'm seeing is with the policy-result leaf under actions.
>>>  It is of type policy-result-type meaning that it can be either
>>>  accept-route or reject-route with a default of reject-route. As per
>>>  section 5.  Policy evaluation, all processing ends when either of
>>>  these is encountered. That would mean only one statement in a policy
>>>  can ever be processed. The first paragraph of section 5 suggests the
>>>  presence of those actions is optional however:
>>>> If the actions include either accept-route or reject-route actions, evaluation of the current policy definition stops, and no further policy statement is evaluated.
>>> 
>>>  In any vendor implementation I'm familiar with it is possible, and
>>>  common in practice, to combine actions (i.e. set a BGP community or
>>>  local-preference) from various statements which are processed in order
>>>  by either implicitly or explicitly continuing on to the next
>>>  statement.
>>> 
>>>  So my proposal here is to remove the default statement from the
>>>  policy-result, which would signify an implicit continuation to the
>>>  next statement. Or with the same net effect, you could add a
>>>  next-statement enum to the policy-result-types to make the choice
>>>  explicit.
>>> 
>>>  I feel like either change would make it much easier to write elegant,
>>>  compact and easy-to-understand policies (and to port existing
>>>  policies). Still, if this goes against your intended design, it would
>>>  be good to fix any wording in the draft that implies that these
>>>  actions are optional.
>>> 
>>>  Thank you,
>>> 
>>>  Kris Lambrechts
>>> 
>>>  _______________________________________________
>>>  rtgwg mailing list
>>>  rtgwg@ietf.org
>>>  https://www.ietf.org/mailman/listinfo/rtgwg
>>> 
>> 
> 
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