Re: [Idr] Does SRGB TLV in draft-ietf-idr-bgp-prefix-sid qualify for BGP Attibute discard?

["Susan Hares" <[e-mail]>]

Eric: 

 

See inline responses. 

 

Sue 

 

From: Eric C Rosen [mailto:[e-mail]] 
Sent: Tuesday, June 26, 2018 3:07 PM
To: Susan Hares; 'Ketan Talaulikar (ketant)'; 'Robert Raszuk'
Cc: 'idr@ietf. org'
Subject: Re: Does SRGB TLV in draft-ietf-idr-bgp-prefix-sid qualify for BGP Attibute discard?

 

On 6/26/2018 2:40 PM, Susan Hares wrote:



If these facts regarding the non-dynamic nature of the changes, then indicate this in the draft-ietf-idr-bgp-prefix-sid draft (or another SR draft and point to it). 


I'll leave that to the authors, but I think this falls under the category of "some familiarity with the normative references is presupposed".

[AFAIK, the normative references do not provide adequate information on the manageability and expectations on the timing for the BGP Peer segments. ] 

On the interaction with routing, you are indicating a routing interaction:  

 “If you do discard-attribute, the prefix is still reachable via the ordinary non-traffic-engineered routing; this does not cause any loops or oscillations, as the ordinary routing is not impacted.” 

You are discussing changes that fluctuate SR routing and ordinary routing. 


I think I already explained why attribute-discard is a more appropriate policy than treat-as-withdraw for a malformed prefix-SID attribute.  

 

[Sue]: The reason we are discussing attribute-discard on this separate thread is because I agree that it is more appropriate that treat-as-withdraw for the malformed prefix-SID attribute.  I would have made comments in 2015 if I thought it was the wrong approach. 


Most BGP attributes have some effect on routing, the question is whether discarding a malformed attribute will result in inconsistent routing (loops).

[Sue] Yes – this is the question I am trying to discuss.  I’ve provided scenarios where it might fail.