On 8/Sep/20 17:55, Douglas Fischer via NANOG wrote:
> Most of us have already used some BGP community policy to no-export > some routes to some where. > > On the majority of IXPs, and most of the Transit Providers, the very > common community tell to route-servers and routers "Please do > no-export these routes to that ASN" is: > > -> 0:<TargetASN> > > So we could say that this is a de-facto standard. > > > But the Policy equivalent to "Please, export these routes only to that > ASN" is very varied on all the IXPs or Transit Providers. > > > With that said, now comes some questions: > > 1 - Beyond being a de-facto standard, there is any RFC, Public Policy, > or something like that, that would define 0:<TargetASN> as > "no-export-to" standard? > > 2 - What about reserving some 16-bits ASN to use > <ExpOnlyTo>:<TargetASN> as "export-only-to" standard? > 2.1 - Is important to be 16 bits, because with (RT) extended > communities, any ASN on the planet could be the target of that policy. > 2.2 - Would be interesting some mnemonic number like 1000 / 10000 or so. The standard already exists... "NO_EXPORT". Provided ISP's or exchange points can publish their own local values to match that within their network, I believe they can do whatever they want, since it's locally-significant. I'm not sure we want to go down the trail of standardizing a "de facto" usage. Just like QoS, it may be doomed as different operators define what it means for them. Mark.
