bgp_community is a special variable that contains route attribute for bgp routes: https://bird.network.cz/?get_doc&v=20&f=bird-6.html#bgp-attr
On Mon, Apr 6, 2020 at 5:18 PM Cybertinus <b...@cybertinus.nl> wrote: > > Hello Fabiano, > > > BGP Communities are basically tags you add to a prefix that is received from, > or send to, a peer. And in Bird you can do whatever you want with these > communities. A community by itself has no meaning and has no influence on the > routing decision whatsoever. It is the meaning you add to it in your > configuration what makes them work. > > More information about communities: > https://en.wikipedia.org/wiki/Border_Gateway_Protocol#Communities > > > Kind regards, > Cybertinus > > > On 2020-04-06 17:03, Fabiano D'Agostino wrote: > > and how these kind of checks are handled? > if (myas,peeras) ~ bgp_community what is bgp_community? > > Thanks, > > Il giorno lun 6 apr 2020 alle ore 15:32 Fabiano D'Agostino > <fabiano.dagostin...@gmail.com> ha scritto: > > Thank you, but "if the route does not come from BGP then false" > here I have: > protocol pipe a { > table master; > mode transparent; > peer table a; > import all; > export where bgp_out(x); => this becomes false, what does this mean? > #export all; > } > > Thanks, > > Il giorno lun 6 apr 2020 alle ore 10:50 Bernd Naumann <b...@spreadshirt.net> > ha scritto: > > On 05.04.20 23:08, Fabiano D'Agostino wrote: > > Good evening, > > could someone explain me the meaning of these lines? > > > > function bgp_out(int peeras) > > { > > if ! (source = RTS_BGP ) then return false; > > if peeras > 65535 then return true; ### communities do not support AS32 > > if (0,peeras) ~ bgp_community then return false; > > if (myas,peeras) ~ bgp_community then return true; > > if (0, myas) ~ bgp_community then return false; > > return true; > > } > > > > Thanks, > > > > Fabiano > > > > Morning, > > I can not cover the whole section but as a start... > > * if the route does not come from BGP then false (routing table source?) > * if the remote AS Number is greater 65535 (16 Bit) then "just" return > true (see AS 32 Bit Numbers, and the non-support of older > devices/implementations) > * For the next 3 I'm not 100% sure how to read but I found > https://bird-users.network.narkive.com/3uDbo6H9/any-ix-willing-to-share-their-config > > ``` > 0:XXXXX - Do not announce route to peer XXXXX > 0:MyASN - Do not announce route to all peers > MyASN:XXXXX - Announce route to peer XXXXX only > MyASN:MyASN - Announce routes to all peers. This community is > automatically added to all routes that are not > tagged with any of MyASN:XXXXX communities. > ``` > > Maybe this helps a little bit. > > Bernd
