Am 25.01.2014 16:38, schrieb Bryan Socha:
Re-reading, I was thinking of someone connecting to an IXP, not a new IXP needing a 2Byte. This is an interesting situation and you are correct, my comment was off topic.
Sorry for not mentioning the beef: Extended Communities effectively leave 6 bytes to the user. So, it is not possible, that a 4-byte-ASN IXP encodes its own 4-byte-ASN and a 4-byte-ASN customer in one extended community string. This is needed, as the IXP RS usually interpret their own ASN and a peer ASN as: "Send this prefix out to the peer ASN". To make things worse: even if the IXPs ASN is 2-byte, I would assume, that RS implementors chose to interpret extended community strings as always being in the format 4-byte:2-byte (see RFC5668). Best regards, Sebastian