[Lsr] Re: WG Last Call for draft-ietf-lsr-igp-ureach-prefix-announce (4/17/2025 - 5/2/2025)

[Aijun Wang]

Hi, Robert: The “UP” I mentioned is the “UP-flag” that introduced in the WGLC document, which is trying to put some maintenance information into the IGP protocol, and should be avoided as declared by several persons already. There maybe many no harm information can be advised by the IGP, but that is not the responsibility of IGP protocol. Aijun Wang China Telecom On Apr 24, 2025, at 06:14, Robert Raszuk <rob...@raszuk.net> wrote:  Aijun, Not sure what you mean by "UP" ... we are not talking about "up signalling".  Make-before-break is not philosophy but operational reality. And if the operator wants a solution to be contained in the IGP what I described will not hurt anyone.  Sure operator may choose to deprefer service layer before planned maintenance and if so additional UPA signalling will do nothing - but will also not hurt anyone.  Thx, R. On Thu, Apr 24, 2025 at 12:06 AM Aijun Wang <wangai...@tsinghua.org.cn> wrote: Hi, Robert and all: “UP” is an unnecessary definition for one imaginary scenario——if make-before-break is the philosophy, why the operator doesn’t switch over in advance the planned maintenance egress PE to other available egress PE on the ingress PE, instead to bother the IGP to accomplish such aim? Aijun Wang China Telecom On Apr 23, 2025, at 22:51, Robert Raszuk <rob...@raszuk.net> wrote:  > ok, I'm fine adding some text for your case. Thx Peter ! It is not "my use case" but ability to trigger UPA for make-before-break which I think always is rather a good thing.  Cheers, R. On Wed, Apr 23, 2025 at 4:40 PM Peter Psenak <ppse...@cisco.com> wrote: Hi Robert, On 23/04/2025 16:35, Robert Raszuk wrote: Hi Peter,  If the egress PE is the only BGP NH, then reacting to max-metric or OL-bit set would make some BGP destinations unreachable. Well this entirely depends on how one reacts on UPA if UPA is signalling the only one left BGP path/NH as down irrespective of the trigger. Does it stop the service to the destination or not ...  If there are alternate paths the best path can install new next hop.  If there are no alternate paths I would rather keep one installed active - for example to address the case where one ABR can still reach egress PE and the other one generated UPA.  So why not trigger UPA in such cases to hint him to switch to alternate next hops if available ? I'm not saying it can not be done. The implementation can chose to advertise the UPA for the summary component prefix if the such prefix metric in the source area/domain crosses certain value or if the prefix originator is overloaded. But this would make it not compliant with current text in section 4 which was the main point of my question. So why not leave the door a bit open for it in the spec ? ok, I'm fine adding some text for your case. thanks, Peter Thx, R. _______________________________________________ Lsr mailing list -- lsr@ietf.org To unsubscribe send an email to lsr-le...@ietf.org _______________________________________________ Lsr mailing list -- lsr@ietf.org To unsubscribe send an email to lsr-le...@ietf.org

_______________________________________________
Lsr mailing list -- lsr@ietf.org
To unsubscribe send an email to lsr-le...@ietf.org