Speaking as WG Member: Hi Chris,
> On Sep 27, 2025, at 6:42 AM, Christian Hopps <[email protected]> wrote: > > Acee Lindem <[email protected]> writes: >>> On Sep 18, 2025, at 11:05 AM, Peter Psenak <[email protected]> wrote: >>> >>> Hi Acee, >>> >>> On 18/09/2025 16:32, Acee Lindem wrote: > >>>>>> The AC-flag simply indicates that the prefix has been configured as >>>>>> anycast - i.e. originated by multiple routers. > >>>> [...] where and how this is configured for a prefix since >>>> we've had the IS-IS Anycast prefix flag for some time. [...] >>> >>> Example from one implementation: >>> >>> router isis 1 >>> interface Loopback0 >>> prefix-attributes anycast >> >> Ok - than this would support keeping the config in the OSPF YANG model as >> Yingzhen has proposed. Authors, let’s keep it there. > > Its not a great solution IMO. I think I agree with the direction of your > earlier questions, (e.g., the property can also be advertised in IS-IS). > Anycast prefix is an IGP agnostic concept -- an anycast prefix is a prefix is > associated with multiple nodes in the network. > > This also isn't an interface wide property it's a prefix property. Someone > earlier said, "most of the time the user doesn't configure multiple prefixes > on their loopback", I'm not sure that's true, especially if we consider > supporting (multiple) anycast application uses along with non-anycast > applications. > > Anyway, to have the only configuration option only cover "most of the time" > cases doesn't seem great. > > A more precise config is to augment the interface prefix configuration > (ietf-ip) as suggested by Acee earlier (I think). I'm afraid we are letting "Prefect be the enemy of good" here. I think if RFC 8344 is to augmented, it needs to be done in a separate document as adding flags to the IP and IPv6 addresses will undoubtedly bring in a larger group of opinions into play and stall this document indefinitely. I understand the reasons for putting it in the IGP model (as Cisco did with their IS-IS configuration). 1. The fact that the prefix is any cast is needed solely by the IGPs. 2. Given #1, it is expedient to add it to the IGP configuration. So, I think the question should be whether or not to leave it as OSPF interface config or do nothing in this draft. I don't feel that strongly on this but am leaning towards leaving it since Cisco already did it that way in their IS-IS configuration. Thanks, Acee > > When ietf-ip was suggested, Yingzhen (I believe), asked how to configure the > protocol to distribute the property then. Why not just distribute it if it > has been set. What is more likely, that the same loopback is configured under > IS-IS and OSPF but you only want to advertise it's anycast property in one of > those IGPs *or* you have anycast and non-anycast prefixes on your loopback? I > think multple prefixes on your loopback is much more likely between those > two. And if you've used multiple loopbacks to support multiple prefixes, well > that solution still works with the ietf-ip augmentation as well. > > Thanks, > Chris. _______________________________________________ Lsr mailing list -- [email protected] To unsubscribe send an email to [email protected]
