Re: [Idr] WG LC on draft-ietf-idr-rpd-05.txt (7/15 to 7/29/2020)

["Jakob Heitz (jheitz)" <[e-mail]>]

Inline.

This draft is nowhere near ready for publication. There are many unspecified items as below.

Regards,
Jakob.

From: Idr <[e-mail]> On Behalf Of Huaimo Chen
Sent: Monday, July 27, 2020 1:57 PM
To: Ketan Talaulikar (ketant) <ketant=[e-mail]>; Robert Raszuk <[e-mail]>; Susan Hares <[e-mail]>
Cc: idr@ietf. org <[e-mail]>
Subject: Re: [Idr] WG LC on draft-ietf-idr-rpd-05.txt (7/15 to 7/29/2020)

Hi Ketan,

    Thanks much for your comments.
    My answers/explanations are inline below with prefix [HC].


>Some more/other comments on why I believe this draft is not a good idea:



     *   How does the controller or provisioning entity know the status of the Route Policy provisioning on the target router. Even that it was successfully propagated to it and installed on it?
[HC]:  It seems that BGP protocols guarantees the BGP UPDATE with the route policy reaches the target router. When a BGP speaker as a controller sends a BGP UPDATE to a peer, there is no need for the ack from the peer about whether it is received, processed, and installed. The controller is monitoring the traffic of the network almost in real time, and adjusting the traffic dynamically almost in real time.. The former gets the status of the network regarding to the traffic.

[Jakob] Then the draft must discuss this. Unless the controller causes probe packets to be sent, it can only guess. The controller must monitor traffic at multiple locations. Which locations and how? Will it inject probe packets if there is no suitable traffic from users?



     *   Seems like one can have multiple policies advertised for a single peer/neighbor? How would they be handled?
[HC]: For multiple policies advertised to a single peer/neighbor, they are processed one by one by the peer/neighbor.

[Jakob] In what order? The draft simply introduces a "Distinguisher", but does not detail how it's used. Are the policies processed in distinguisher order? Other possibilities are to execute just one policy or to consider the case an error. The draft must discuss.


     *   The draft has support for IPv4 and IPv6 prefix list and AS regex. What other route policy tools does the WG expect to extend in further drafts? Perhaps we end up with yet another boatload of extension drafts for BGP for RPD?
[HC]: It seems that the current draft defines a small set of extensions (6 sub TLVs), which is enough to support adjusting the traffic dynamically in the live networks. If there are some new requirements in the future, the extensions would be small too.

[Jakob] These are not enough to apply a different policy to each BGP neighbor of a speaker.
The draft states:
Users define a set of matching rules based on
       different attributes of routes, such as the destination address
       and the address of the router that advertises the routes.
However, there is no TLV to specify the router that advertises the route.
The router that advertises the route only makes sense for import policies. For export policies, it must be the router to which the route is advertised, but again, the draft makes no provision for that.



We have Route Policy yang model defined at the IETF for provisioning of route policies that provide better and more comprehensive solution than the proposal in this document. That approach is also very robust from operational perspective. We don't need to be putting this into BGP protocol.
[HC]: Yang model seems mainly used in relatively static or stable configurations. For frequently changing route policies, the solution proposed in the draft is more suitable. It makes the operations and maintenance on the network simpler. For example, in one metro area network without using the solution in the draft, planning and implementing an adjustment/redirection of a service traffic takes days. After the solution in the draft is deployed in the network with a controller NCE, this takes just minutes instead of days.

Best Regards,
Huaimo
________________________________
From: Idr <[e-mail]<mailto:[e-mail]>> on behalf of Ketan Talaulikar (ketant) <ketant=[e-mail]<mailto:ketant=[e-mail]>>
Sent: Thursday, July 23, 2020 6:02 AM
To: Robert Raszuk <[e-mail]<mailto:[e-mail]>>; Susan Hares <[e-mail]<mailto:[e-mail]>>
Cc: idr@ietf. org <[e-mail]<mailto:[e-mail]>>
Subject: Re: [Idr] WG LC on draft-ietf-idr-rpd-05.txt (7/15 to 7/29/2020)


+1 and I also agree on Jakob's comments/discussion on a parallel thread.



The individual version of this draft was called draft-li-idr-flowspec-rpd. When it came up for WG adoption, perhaps most people thought it was yet another Flowspec extension and did not have a close look at it.



The draft got adopted in Nov 2019 and since then, there has hardly been any change for it (other than IANA allocations update) : https://www.ietf.org/rfcdiff?url1=draft-ietf-idr-rpd-00&url2=draft-ietf-idr-rpd-05<https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.ietf.org%2Frfcdiff%3Furl1%3Ddraft-ietf-idr-rpd-00%26url2%3Ddraft-ietf-idr-rpd-05&data=02%7C01%7Chuaimo.chen%40futurewei.com%7C28cc9cc452284af4ab3508d82eef9d08%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C0%7C637310953981956964&sdata=vUgOeTbdLbvoAWIi17vzORiS8UxREO4JoanDDuuGodM%3D&reserved=0>



I am not sure if this document has received sufficient review and inputs from the WG over the recent 9 months of its life as a WG document. Those provided by Robert previously seem not to have been incorporated?



Not sure if I missed implementation reports or some operator feedback on this.



Some more/other comments on why I believe this draft is not a good idea:



  *   How does the controller or provisioning entity know the status of the Route Policy provisioning on the target router. Even that it was successfully propagated to it and installed on it?
  *   Seems like one can have multiple policies advertised for a single peer/neighbor? How would they be handled?
  *   The draft has support for IPv4 and IPv6 prefix list and AS regex. What other route policy tools does the WG expect to extend in further drafts? Perhaps we end up with yet another boatload of extension drafts for BGP for RPD?



We have Route Policy yang model defined at the IETF for provisioning of route policies that provide better and more comprehensive solution than the proposal in this document. That approach is also very robust from operational perspective. We don't need to be putting this into BGP protocol.



In summary, my suggestion would also be not proceed further on this document.



Thanks,

Ketan



From: Idr <[e-mail]<mailto:[e-mail]>> On Behalf Of Robert Raszuk
Sent: 17 July 2020 18:38
To: Susan Hares <[e-mail]<mailto:[e-mail]>>
Cc: idr@ietf. org <[e-mail]<mailto:[e-mail]>>
Subject: Re: [Idr] WG LC on draft-ietf-idr-rpd-05.txt (7/15 to 7/29/2020)



Dear IDR WG,



As discussed previously on the list I strongly object to proceed with this draft any further.



While I am as others quite sceptical about distributing more configuration over BGP this can be said to be debatable especially for p2mp applications.



However including peer's IP address in the NLRI to which given policy applies goes completely AGAINST BGP spray principle of p2mp information distribution. Adding such extension to BGP can only deteriorate the protocol further. It is not a fit in p2mp protocol to by definition use it as p2p transport channel.



The prefix 0 which is in the draft is not the solution to the above problem..



Moreover wide community ATOM also can already contain that peer's address so placing it in the NLRI of MP_REACH is not needed at all.



To the specific questions asked:



Ad 1) No.

Ad 2) No.

Ad 3) No..

Ad 4) No.

Ad 5) Yes.



Kind regards,

R.





On Wed, Jul 15, 2020 at 3:11 PM Susan Hares <[e-mail]<mailto:[e-mail]>> wrote:

This begins a 2 week WG LC on draft-ietf-idr-rpd

from 7/15 to 7/29/2020.  You can obtain this draft at:

https://datatracker.ietf.org/doc/draft-ietf-idr-rpd/<https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fdraft-ietf-idr-rpd%2F&data=02%7C01%7Chuaimo.chen%40futurewei.com%7C28cc9cc452284af4ab3508d82eef9d08%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C0%7C637310953981966953&sdata=te9utkoi5bJl%2BT167KdWJQ%2BHYXaOaogxnvPQZLvbbWI%3D&reserved=0>



This draft defines a new AFI/SAFI and new atoms

for the Wide Communities.  This WG LC has been delayed

as I waited for a resubmission of the Wide Communities draft.

I had hoped to do these 2 WG LC in parallel.



I've not received the Wide Communities draft, but we will

start this WGLC to provide feedback to the authors.

We may have to run a short follow-up to this WG LC

If there are changes to the Wide Communities draft during

Its WG LC.



There is an IPR statement on this draft.



In your responses please answer the following questions:



1) Do you feel this draft has an solution that is acceptable

   With the IPR as a WG RFC?



2) Do you feel this draft is ready to publish?



3) Do you know of implementations of this draft?



4) Do you know of deployments of this draft?

If so, is this feature useful in the deploy ments.



5) Do you feel that Wide Communities is ready for

Publication?



Cheerily, Susan Hares

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