On Mon, Jul 11, 2022 at 08:18:07PM +0100, Stuart Henderson wrote: > On 2022/07/11 19:12, Claudio Jeker wrote: > > This is my try at documenting the just added add-path bits. > > > > -- > > :wq Claudio > > > > +per prefix. > > +Which paths are sent depends on the mode: > > +.Pp > > +.Bl -tag -width as-wide-best -compact > > +.It Ic all > > +send all valid prefixes > > Never used add-path so I might misunderstand things, but shouldn't this > be "send all valid paths" (and same in other descriptions)?
Indeed, as you can see this confuses me as well :) > > +.It Ic best > > +send the best prefix and maybe more > > perhaps s/more/others/ > > this makes me wonder exactly what "best" and "more" are I just removed the 'and maybe more'. If you use just 'announce add-path send best' it will result in the default behaviour and only announce one path. > > +.It Ic ecmp > > +send prefixes with equal nexthop cost > > +.It Ic as-wide-best > > +send prefixes where the fist 8 check of the decision process match > > ...where the first 8 checks of the decision process... > I wonder if this should be changed to: send out paths that evaluate the same up but not including the nexthop metric Only problem is that the decision process documented in bgpd(8) does not mention where this check is (since we don't have nexthop metrics). Updated diff below including changes suggested by jmc@ -- :wq Claudio Index: bgpd.8 =================================================================== RCS file: /cvs/src/usr.sbin/bgpd/bgpd.8,v retrieving revision 1.74 diff -u -p -r1.74 bgpd.8 --- bgpd.8 28 Jun 2022 11:52:24 -0000 1.74 +++ bgpd.8 11 Jul 2022 13:22:05 -0000 @@ -401,6 +401,16 @@ has been started. .Re .Pp .Rs +.%A D. Walton +.%A A. Retana +.%A E. Chen +.%A J. Scudder +.%D July 2016 +.%R RFC 7911 +.%T Advertisement of Multiple Paths in BGP +.Re +.Pp +.Rs .%A C. Petrie .%A T. King .%D May 2017 Index: bgpd.conf.5 =================================================================== RCS file: /cvs/src/usr.sbin/bgpd/bgpd.conf.5,v retrieving revision 1.223 diff -u -p -r1.223 bgpd.conf.5 --- bgpd.conf.5 28 Jun 2022 11:52:24 -0000 1.223 +++ bgpd.conf.5 12 Jul 2022 15:12:30 -0000 @@ -843,6 +843,57 @@ The default is .Ic no . .Pp .It Xo +.Ic announce add-path send +.Pq Ic no Ns | Ns Ic all +.Xc +.It Xo +.Ic announce add-path send +.Pq Ic best Ns | Ns Ic ecmp | Ns Ic as-wide-best +.Op Ic plus Ar num +.Op Ic max Ar num +.Xc +If set to +.Ic all , +.Ic best , +.Ic ecmp , +or +.Ic as-wide-best , +the send add-path capability is announced, which allows sending multiple paths +per prefix. +Which paths are sent depends on the mode: +.Pp +.Bl -tag -width as-wide-best -compact +.It Ic all +send all valid paths +.It Ic best +send the best paths +.It Ic ecmp +send prefixes with equal nexthop cost +.It Ic as-wide-best +send prefixes where the first 8 checks of the decision process match +.El +.Pp +.Ic plus +allows the inclusion of additional backup paths and works for +.Ic best , +.Ic ecmp , +and +.Ic as-wide-best . +.Ic max +can be used to limit the total amount of paths sent for +.Ic ecmp +and +.Ic as-wide-best . +The default is +.Ic no . +.Pp +Right now +.Ic ecmp +and +.Ic as-wide-best +are equivalent. +.Pp +.It Xo .Ic announce as-4byte .Pq Ic yes Ns | Ns Ic no .Xc
