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 -- [email protected]
To unsubscribe send an email to [email protected]

Reply via email to