BGP: Do not prepend ASN in export from non-RS EBGP to RS EBGP
When route is exported to regular EBGP, local ASN should be prepended to AS_PATH. When route is propagated by route server (between RS-marked EBGP peers), it should not change AS_PATH. Question is what to do in other cases (from non-RS EBGP, IBGP, or locally originated to RS EBGP). In 1.6.x, we did not prepend ASN in non-RS EBGP or IBGP to RS EBGP, but we prepended in local to RS EBGP. In 2.0.x, we changed that so only RS-EBGP to RS-EBGP is not prepended. We received some negative responses (thanks to heisenbug and Alexander Zubkov), we decided to change it back. One reason is that it is simple to modify the AS_PATH by filters, but not possible to un-modify changes done by BGP itself. Also, as 1.6.x behavior was not really consistent, the final behavior is that ASN is never prepended when exported to RS EBGP, like to IBGP. Note that i do not express an opinion about whether such configurations are even reasonable.
Showing with 1 addition and 2 deletions