> ...especially when it is already implemented by other vendors.

Cisco NXOS does similar, yea:

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus9000/sw/93x/unicast/configuration/guide/b-cisco-nexus-9000-series-nx-os-unicast-routing-configuration-guide-93x/b-cisco-nexus-9000-series-nx-os-unicast-routing-configuration-guide-93x_chapter_011110.html#id_123700

> You can configure BGP Interface Peering via IPv6 Link-Local for IPv4 and IPv6 Address Families for automatic BGP neighbor discovery using unnumbered interfaces. Doing so allows you to set up BGP sessions using an interface name as a BGP peer (rather than interface-scoped addresses). ***This feature relies on ICMPv6 neighbor discovery (ND) route advertisement (RA) for automatic neighbor discovery and on RFC 5549 for sending IPv4 routes with IPv6 next hop.***

On Thu, Jul 14, 2022 at 9:09 AM Ondrej Zajicek <santiago@crfreenet.org> wrote:

On Thu, Jul 14, 2022 at 05:36:20PM +0200, Marco d'Itri wrote:
> On Jul 14, Ondrej Zajicek <santiago@crfreenet.org> wrote:
>
> > > RFC 8950 is what has been implemented in Cumulus.
> > Not sure how that is relevant, RFC 8950 is just IPv6 next hop for IPv4
> > routes, it does not handle BGP neighbor discovery.
> Discovery is just looking at Router Advertisements for the link, then
> you need RFC 8950.

Hmm, using Router Advertisements for BGP neighbor discovery is an
interesting idea, especially when it is already implemented by other
vendors.

We already have support for extended next hop (RFC 5549, where RFC 8950
is just a minor update).

--
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago@crfreenet.org)
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"To err is human -- to blame it on a computer is even more so."